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2001-2002 Report ofTomato Research
Supported by theFlorida Tomato Committee
1022 McCarty Hall / PO Box 110200Gainesville, FL 32611-0200
Phone: (352) 392-1784 / Fax: (352) 392-4965E-mail: [email protected]
WWW: http://research.ifas.ufl.edu
Equal Opportunity/Affirmative Action Institution
Office of the Dean for ResearchFlorida Agricultural Experiment Station
MEMORANDUM
TO: The Florida Tomato Committee
FROM: Mary L. Duryea, Assistant Dean for Research
SUBJECT: 2001-2002 Research Report
DATE: September 5, 2002
This report describes research in UF/IFAS/FAES that received support from the Florida Tomato Commit-
tee during the past year. The Florida Tomato Committee support combines with State and Federal re-
sources providing critical operating support that allows IFAS tomato scientists to have a strong research
program focused on the tomato industry of Florida.
This is an extremely important partnership between the Tomato Industry and IFAS scientists. We have
worked together to identify the questions and needs for the industry. Then, again together we have priori-
tized the research to be accomplished. This year’s work ranged from methyl bromide alternatives to
tomato breeding to post-harvest handling, lycopene recovery and finally, marketing issues. Many of the
results are immediately applicable by the industry.
We hope to continue in our quest for improving production methods and product quality. We are pleased
to have the Florida Tomato Committee as a partner in programmatic support for tomato research. On
behalf of the scientists involved in tomato research, we thank you and appreciate your support.
This report of research results is presented in electronic format. We hope you find the information in the
report useful to all facets of tomato production.
MLD:las
Page Title Investigators
Control of Fusarium Crown Rot, Rootknot Nematodes andNutsedge with Soil Fumigants and Herbicides in SouthwestFlorida
James P. GilreathJoseph W. NolingErin N. Rosskopf
1
Residual Effects of Fumigant Alternatives on Nutsedge,Rootknot Nematode, and Fusarium Wilt of Fall Tomato andDouble Crop Cucumber/Cover Crop Production
James P. GilreathJoseph W. NolingJohn P. JonesPhyllis R. Gilreath
48
Development and Evaluation of a Biologically-Based Systemand a Chemically-Based Alternative System to Methyl Bromidefor Tomato Production in Miami-Dade County
64Waldemar KlassenHerbert H. BryanRobert T. McMillanYuncong LiQ. R. WangA. Abdul-BakiM. CadalloZ. A. HandooD. Chitwood
Breeding Tomatoes for Florida69 John W. Scott
Breeding Tomatoes for Resistance to all Three Races of theBacterial Spot Pathogen
John W. ScottJeffrey B. Jones74
Selection of Tomato Lines for Commercial Markets that Exhibita Fruit/Floral Character within a Balanced Sugar, Acid andVolatile Profile
77 Elizabeth A. BaldwinJohn W. Scott
Mining Gold in Florida: Feasibility of Lycopene and Novel By-Products Recoveries from Cull Tomatoes via Post-HarvestManipulations, Dehydration and CO2 Super Critical Extraction
83Amy SimmoneBala RathinasabapathiStephen T. TalcottSteven A. SargentJeffrey K. BrechtMurat O. BalabanMaurice R. Marshall
Sanitation to Eliminate Hazardous Microorganisms fromTomato Fruit
Jerry A. BartzKeith R. SchneiderKelly FelkySteven A. Sargent
Competition in the Winter Fresh Tomato Market John J. VanSickle
INDEX
FLORIDA TOMATO COMMITTEE2001-2002 IFAS Research Reports
96
101
1
Control of Fusarium Crown Rot,Rootknot Nematodes and Nutsedgewith Soil Fumigants and Herbicides inSouthwest Florida
James P. Gilreath, Joseph W. Noling and Erin N.
Rosskopf
AbstractFunding from the Florida Tomato Commit-
tee was leveraged with funding from the USDA /
IR-4 methyl bromide alternatives program to
support two large field experiments with as many
as 24 different fumigant treatments in Immokalee
in the spring of 2002 and in Bradenton during the
fall of 2001. The Bradenton experiment targeted
nutsedge, nematodes and Fusarium wilt, race 3;
whereas, the Immokalee trial focused on Fusarium
crown rot on a commercial farm. Labeled fumi-
gants, as well as experimental ones, were evaluated
in these experiments. Telone C-35 applied broad-
cast with a herbicide followed by additional chlo-
ropicrin in the bed provided good control of most
pests as did Inline applied via drip irrigation tubing
with herbicide broadcast. Combining Basamid
with Telone C-35 was effective for some pests but
yields appeared to suffer somewhat. Application
of metam sodium (Vapam) or metam potassium
(K-Pam) to the bed top through 3 drip irrigation
lines provided good pest control and yield compa-
rable to or better than methyl bromide in both
studies. Fosthiazate was effective when combined
with chloropicrin and Tillam, but some questions
remain about proper application procedures with
fosthiazate as well as Plant Pro and AU 110, both
of which did not provide good pest control in this
study. Results with Multiguard suggest we need to
do conduct additional research on application
technique to improve efficacy. Iodomethane
requires the addition of chloropicrin to enhance
soilborne pest control. While good data were
obtained on Fusarium wilt control, data for
Fusarium crown rot were less definitive as the pest
pressure was not high enough due to the unseason-
able weather during the spring of 2002. Methyl
bromide provided no control of crown rot in the
Immokalee trial. Some treatments which ap-
peared favorable for at least partial control of
crown rot included Plant Pro 20EC, Fosthiazate
applied via drip irrigation with 200 lb/acre of
chloropicrin in the bed, 100 lb/acre of AU 110 and
600 lb/acre of Multiguard. While no solid solu-
tions for Fusarium crown rot have been derived
from this work, a foundation has been laid for
future work, provided funding continues and we
are able to leverage the support of the Florida
Tomato Committee with that of other organizations
or agencies, like the USDA / IR-4 program.
Soil fumigant research has been conducted
at the Gulf Coast Research and Education Center
for over 30 years under the leadership of several
different scientists. In 1991, prior to the an-
nounced phase out of methyl bromide, this re-
search was accelerated and the program began a
slow, but steady increase in size and scope to
encompass the major soilborne pests in one orga-
nized research program. Although many different
methyl bromide alternatives have been evaluated
by this research group as part of the program,
much of the more recent work has focused on the
most likely alternatives for the immediate future,
rather than diluting resources by continuing screen-
ing efforts for new compounds. In 2001, we were
asked to take over operation of the USDA / IR-4
Methyl Bromide Alternatives Program. This
provided us with funding opportunities which ,
when combined with funding from the Florida
Tomato Committee, allowed us to develop a more
aggressive research program in the area of poten-
tial new alternatives for the Florida tomato grower.
Initially, we were committed to conduct a fumigant
study in southwest Florida focusing on Fusarium
crown rot; however, the additional funding pro-
vided by the IR-4 program allowed us to look at
more alternatives than originally planned and to
expand the work to include a second study, thereby
“hedging our bets”.
Fusarium crown rot has become a major
soilborne pest in southwest Florida tomato fields,
whereas Fusarium wilt is more prevalent in the
west central production area. Fusarium crown rot
and Fusarium wilt are caused by different subspe-
cies of the same fungal pathogen Fusarium
oxysporum. Fusarium crown rot is favored by
cooler soil temperatures than Fusarium wilt and
2
symptoms of the two are quite different. The most
notable physical difference is the absence of the
brilliant yellowing associated with Fusarium wilt
on plants infested with Fusarium crown rot. In
spite of their differences in appearance and envi-
ronmental conditions necessary for disease devel-
opment, control of Fusarium crown rot and wilt is
reported to be similar. For example, increasing soil
pH above 6.5 and reduction in usage of ammonium
containing fertilizer can aid in management of both
diseases. Soil fumigation with methyl bromide /
chloropicrin mixtures can be effective against
Fusarium wilt, but some question its effectiveness
against Fusarium crown rot because crown rot
incidence has increased in spite of universal use of
methyl bromide. Fusarium oxysporum produces
chlamydospores which are thick-walled spores
capable of surviving in soil and plant debris for
many years. The thickness of the spore walls also
may provide some protection from soil fumigants,
especially if the fumigant rate is low or the product
dissipates too quickly after application.
Rootknot nematodes and nutsedge (both
yellow and purple) also are serious soilborne pests
in tomato production. While methyl bromide /
chloropicrin mixtures generally provide good
control of these pests, many alternatives do not.
The single greatest challenge for growers in gen-
eral is nutsedge control; however, the greatest crop
reduction comes from a combination of all three
pest groups (nutsedge, nematodes, and soilborne
disease). Research conducted during 2001 - 2002
attempted to focus on all three pests, but greater
emphasis was placed on Fusarium crown rot than
other pests. Since crown rot and Fusarium wilt are
closely related and are said to respond similarly to
many control measures, two trials were conducted.
One trial was conducted in the Immokalee area on
a commercial tomato farm where Fusarium crown
rot was reported to be a major problem. A similar
experiment was conducted at the Gulf Coast
Research and Education Center in Bradenton in an
area with an established population of nutsedge,
rootknot nematode and Fusarium wilt. Treatments
in each experiment were replicated 4 to 5 times
and plot size ranged from 50 to 100 ft. There were
16 treatments at Bradenton and 24 at Immokalee.
All fumigants and herbicides were applied with
commercial equipment. Alternatives evaluated
consisted of methyl bromide, methyl iodide,
Telone C-35, Telone II, metam sodium (Vapam),
metam potassium (K-Pam), chloropicrin, Plant Pro,
fosthiazate, Basamid, Enzone, AU 110, Inline, and
Multiguard. Many of these products were used in
combination to enhance performance or cover
weak areas in their efficacy spectrum. The experi-
ment at Bradenton was initiated in mid August of
2001 with planting in late September for a fall crop
while fumigants in the Immokalee trial were
applied the week before Christmas for a spring
crop which was planted in late January. Planting
was delayed in Bradenton due to excessive soil
moisture and the complexity of some of the treat-
ments. Many of the alternative treatments con-
sisted of three or more pesticides and each had
specific application procedures and waiting periods
to be accommodated which increased the time
required to complete treatment applicaiton.
Data were collected for control of nutsedge,
nematodes, Fusarium wilt and crown rot, and crop
response, including fruit production by size grade
at each trial location. Because of the large number
of treatments and the quantity of data collected,
results only will be discussed in general terms.
Bradenton experiment:The first experiment was conducted in the
fall of 2001 at the GCREC in Bradenton to get the
bugs out of conducting such large tests before
initiating a study in a commercial field in
Immokalee. At Bradenton, tomato plant vigor was
reduced by Plant Pro and Enzone (Table 1). Nut-
sedge control was best with methyl bromide,
iodomethane (methyl iodide, trade name Midas),
broadcast Telone C-35 with Treflan + Devrinol
followed by additional chloropicrin in the bed, 75
gallons of metam sodium per acre applied through
3 drip tubes on top of the 28 inch-wide bed top,
Tillam broadcast with fosthiazate (rototilled in the
bed or drip applied) and chloropicrin in the bed,
Basamid with Telone C-35, and Treflan followed
by Telone C-35 with biweekly applications of
Messenger (Table 3). Good Fusarium wilt control
was provided by all treatments, except
Iodomethane without chloropicrin, Plant Pro, and
Enzone (Table 4). Although rootknot nematodes
3
were present in the test area prior to initiation,
excessive water at the beginning of the season
reduced the population and it never recovered
enough to distinguish differences among treat-
ments for rootknot control (Tables 5 and 6). Con-
trol of stunt nematodes was good with methyl
bromide, Telone C-35, 75 gallons per acre of
metam sodium with or without chloropicrin,
fosthiazate with chloropicrin, and Basamid with
Telone C-35. Sting nematodes were present but
not in sufficient numbers to cause economic
damange. Interestingly, cyst nematodes generally
are not thought of as being present in tomato fields,
but they were detected in a number of plots in this
study. Documentation of their presence in tomato
in west central - southwest Florida is important
because it provides justification for higher rates of
Telone C-35 per label instructions for those grow-
ers who may wish to use it. Enzone was the only
product to have more root galling than methyl
bromide as a result of rootknot nematodes (Table
7).
Tomato fruit yields were obtained from two
harvests at Bradenton (Tables 8 and 9) and data
were combined to provide season total yield in
each size grade. Metam sodium (e.g. Vapam) at 75
gal/acre applied through 3 drip tubes was the only
alternative to produce more extra large (5 x 6) size
fruit in the first harvest than methyl bromide and
yield was greater than that obtained with
iodomethane alone, metam + Telone II, metam +
Plant Pro, fosthiazate incorporated into the bed
with a rototiller, Basamid + Telone C-35, Enzone,
or Telone C-35 + Messenger (Table 8). There
were no differences in production of extra large
fruit in the second harvest (Table 9). Differences
among treatments in season total production were
similar to those observed in each of the two har-
vests (Table 10). Total extra large (5 x 6) fruit
production was similar to methyl bromide with
many of the treatments; however, metam produced
more than iodomethane, broadcast Telone C-35
with chloropicrin in bed, Plant Pro, in bed
fosthiazate, Basamid + Telone C-35, Enzone or
Telone C-35 with Messenger. Minor differences
existed in production of large (6 x 6) and medium
(6 x 7) size fruit in each harvest and season total,
but most of the production and differences were in
the extra large category. There were few differ-
ences in total marketable yield at Bradenton and
those which produced fewer extra large fruit in the
individual harvests produced fewer when yields
were totaled. Overall, the most promising treat-
ments in the fall at Bradenton, based on all pests
and yield, were Telone C-35 broadcast with herbi-
cide and additional chloropicrin applied to the bed,
iodomethane (Midas) with chloropicrin, metam
sodium (e.g. Vapam) applied through 3 drip tubes
per bed, and Fosthiazate drip applied with chlo-
ropicrin in bed and Tillam herbicide.
Immokalee experiment:The spring trial in Immokalee contained
more experimental compounds than the fall experi-
ment in Bradenton. Vigor of tomato plants (visual
estimate of plant health and growth) was estimated
about 3 weeks after planting and again near first
harvest. Early vigor estimates indicated little
difference in tomato plant vigor with most treat-
ments when compared to methyl bromide; how-
ever, the highest two rates of AU 110 reduced plant
vigor, but only the highest rate was significantly
less vigorous than methyl bromide (Table 11). A
clear dose response relationship was observed with
this product - as the rate increased, plant vigor
declined. Since this was the first time we had
worked with this product, we were learning how to
apply it and have made some changes since then
which will be reflected in future work. Thus,
although we observed phytotoxicity with this
product, it may have been the result of application
procedure or insufficient waiting period after
application. There were no differences in plant
vigor among treatments later in the season.
As previously indicated, the test site in
Immokalee was selected for its historical problem
with Fusarium crown rot. Methyl bromide had no
effect on crown rot in this experiment (Table 12).
Fifteen percent of the tomato plants in the methyl
bromide plots were infested with crown rot; the
same incidence level as the nontreated control.
Few differences were observed among fumigants
in this study, partially because the infection level
was so low. Early in the season Fusarium crown
rot was observed on a few young plants, but the air
and soil temperatures rose quickly in the spring as
4
unseasonably warm weather occurred early and
persisted for much of the spring. Once the opti-
mum soil temperature for crown rot (70 degrees
Fahrenheit) was exceeded, pathogen growth
slowed and disease incidence ceased to increase.
Some treatments which appeared favorable for at
least partial control of crown rot included Plant Pro
20EC, Fosthiazate applied via drip irrigation with
200 lb/acre of chloropicrin in the bed, 100 lb/acre
of AU 110 and 600 lb/acre of Multiguard. While
the incidence of crown rot with AU 110 appeared
to increase with higher rates, part of that increase
may have been due to early season phytotoxicity as
the incidence of crown rot was determined by
counting the number of dead plants as well as
those with actual symptoms of crown rot, since
most plant mortality appeared to be associated with
crown rot.
The experimental site near Immokalee also
was purported to have a considerable population of
nutsedge, but it did not as a result of the grower’s
persistence with a program of fallow applications
of Roundup and/or Touchdown followed by
disking. There were very few weeds present in the
beds at this site. Row middles were heavily in-
fested with nightshade, but none were observed in
the beds. The only weed affected by methyl
bromide alternatives was goosegrass (Table 13).
The number of goosegrass plants per 100 ft of row
was the least in the nontreated control plot. Sig-
nificantly more goosegrass was present in beds
treated with iodomethane and the 150 lb rate of AU
110. This site had very few nematodes in the soil.
As a result, there were no significant differences
among treatments (Table 14). Tomato plant roots
were examined at the end of the season and no
rootknot nematode gall production was observed
with any treatment.
Tomatoes were harvested three times,
sorted into marketable and cull based on external
appearance factors as instructed by the grower and
the farm owner, then the marketable fruit were
separated into size grades using a portable grader
with size standards conforming to those established
by the industry. Production of extra large (5 x 6)
fruit was affected in the first harvest only (Table
15), while medium size fruit (6 x 7) were the only
size affected by treatment in the second and third
harvests (Tables 16 and 17). Season total produc-
tion of extra large fruit was reduced (compared to
methyl bromide) where soil was treated with
metam sodium + Telone II and the two highest
rates of AU 110; again, most likely as a result of
early phytotoxicity with AU 110 (Table 18). Pro-
duction of medium size fruit relative to methyl
bromide was higher with metam sodium + Plant
Pro 20EC, but none of the treatments affected total
marketable fruit production in this study.
Overall, several alternatives appear promis-
ing. Broadcast application of Telone C-35 contin-
ues to show good efficacy when combined with a
herbicide and followed by additional chloropicrin
in the bed. The performance of iodomethane was
not as good as expected, but results of this study
point out the importance of combining this fumi-
gant with chloropicrin to achieve disease control.
Metam (Vapam and K-Pam) demonstrated good
efficacy in these two experiments when applied at
the full label rate to the bed top through 2 or more
drip irrigation lines. The number of lines depends
upon the bed width. Beds wider than 24 inches
appear to require 3 lines on the bed top. In some
cases, the addition of chloropicrin to the bed seems
to improve metam performance. While metam
performance has been erratic in the past, the
percentage of success has increased in the past year
as results of our related studies on water and dye
movement in the soil have been integrated into our
research. Fosthiazate combined with chloropicrin
and a herbicide appeared to have some promise,
but more work is needed on the proper application
procedure for fosthiazate. Inline performed well
in combination with Treflan and Devrinol and
more research is planned with it. Plant Pro prod-
ucts did not perform that well in these experiments,
but there is a question as to what is the proper
application procedure for these materials. That
question will be researched further in a separate
study. AU 110 was shown to be very effective in
previous research by the senior author of this
report; however, the formulation has changed and
we are still working on the proper formulation as
well as the most effective delivery method for it.
By leveraging the funding from the Florida
Tomato Committee with that from the USDA / IR-
4 methyl bromide alternatives program we have
5
been able to expand our research program, both in
terms of production regions and pests, and we hope
to continue this work in the coming years so that
we can deliver to the tomato industry practical
options for soil fumigation and better control
measures for Fusarium wilt and Fusarium crown
rot in addition to nutsedge and nematodes.
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Residual Effects of Fumigant Alterna-tives on Nutsedge, Rootknot Nematode,and Fusarium Wilt of Fall Tomato andDouble Cropped Cucumber / CoverCrop Production Fall 2001 - Spring 2002
James P. Gilreath, Joseph W. Noling, John P.
Jones and Phyllis R. Gilreath
Abstract. Results of the first four years of a five year study
indicate that mixtures of Telone and chloropicrin
(Telone C-17 or C-35), combined with Tillam
herbicide, are as effective as mixtures of methyl
bromide with chloropicrin (67/33 formulation) for
control of nutsedge, rootknot and other nematodes,
and fusarium wilt (race 3) in tomato and double
cropped cucumber. Tomato and cucumber produc-
tion was similar with Telone C-17 and methyl
bromide. Soil solarization using clear plastic
mulch to heat the soil for 8 weeks was intermediate
in its efficacy; that is, it generally was better than
applying no fumigant but was not as effective as
methyl bromide or Telone C-17 plus Tillam.
Solarization appeared to favor rootknot nematode
development, but the increased incidence com-
pared to the nontreated control was due to a lack of
root system for the control plants due to crop loss
as a result of fusarium wilt. Resurgence of nema-
todes was a problem with all treatments, including
methyl bromide, and rootknot nematodes were
quite plentiful on double cropped cucumber as a
result. Thus far, the spring cropping systems have
not had that much of an effect on the fall tomato
crop with the exception that stubby root nematode
was reduced following millet as a spring cover
crop and there appeared to be a trend for double
cropped cucumbers to increase the rootknot nema-
tode population in fall tomato. Completion of the
next two years of this study should determine
whether or not there is any truth to the theory that
alternative fumigant efficacy will decline with time
as residual effects of previous methyl bromide use
diminish.
Since 1993 research has been conducted at
the Gulf Coast Research and Education Center to
identify alternatives to methyl bromide and their
strengths and weaknesses. Additionally, we have
strived to find ways to improve efficacy with
various alternatives, whether it be through im-
provements in application technology or selection
of combinations of materials to overcome inherent
weaknesses in one product. Recognizing the
potential impact of the impending loss of methyl
bromide as a soil fumigant and the concern that
growers have about the long term effects of adopt-
ing alternative practices, a multi-year study was
initiated in the fall of 1998 to determine the effi-
cacy of a chemical and a nonchemical alternative
for soilborne pest control in fall tomato and spring
cropping systems. This study has been funded by
the Florida Tomato Committee, the USDA - ARS,
FFVA and Dow AgroSciences and is the only study
of its kind in the world.
This long term study compares the current
chemical replacement for methyl bromide, Telone
C-17 (contains 17% chloropicrin as compared to
35% in Telone C-35, at the beginning of this study
in 1998 only C-17 was available), and the best
nonchemical alternative, soil solarization, to
methyl bromide for broadspectrum soilborne pest
control in fall tomato. It also examines the effects
of these fall-applied alternatives on spring double-
cropped cucumber and millet grown as a cover
crop. In addition to the effects of the alternatives
on spring cropping practices, the study also investi-
gates the residual effects of the spring cropping
practices (double cropped cucumber, millet and
weed fallow) on the soilborne pests and crop for
tomato the following fall. Telone C-17 (35 gal/
acre) in the bed has been combined with Tillam
herbicide (4 lb.a.i./acre) applied broadcast prior to
bed formation for the first two years. Beginning in
the third year (fall 2000), Devrinol (2 lb.a.i./acre)
was tank mixed with Tillam to improve pigweed
and crabgrass control. Soil solarization was
conducted by covering beds with clear plastic
mulch for 8 weeks then painting the mulch film
white prior to planting tomato. In the summer of
2000, the solarization treatment was modified by
broadcast incorporating Devrinol herbicide (2
lb.a.i./acre) prior to bed formation in an attempt to
improve overall weed control. Methyl bromide /
chloropicrin mixture (67/33 @ 350 lb/acre) was
applied to the bed in the same fashion as Telone C-
49
17 using 3 chisels per bed. A nontreated control
was included to allow monitoring of pest popula-
tions and determination of actual control of indi-
vidual soilborne pests. This study is now begin-
ning its fifth year.
The study was designed to answer many
questions but the most important probably was
what happens over time when we continually use
these alternatives and the effect of previous methyl
bromide use is diminished. Over the first four
years of fumigation for fall tomato followed by
spring double cropping, millet cover crop or fallow
practices we have seen large fluctuations in nut-
sedge and nematode populations but a more stable
incidence level of Fusarium wilt, race 3, which has
averaged about 95% in the nontreated controls
since the second year of this study. This past year
(fall 2001) we observed resurgence of rootknot
nematodes near the end of the fall tomatoes with
all treatments.
Tomato plant vigor early in the season
during the fourth fall crop season was not affected
that much by treatment, other than the reduction in
vigor where no fumigant or alternative is used
(Table 1). By midseason plant vigor was reduced
some by soil solarization, but not to the extent as
observed in past years. Spring cropping practice
had no effect on fall tomato plant vigor during
2001.
Weed control was interesting this year
(Table 2). Both alternative treatments controlled
nutsedge as well as methyl bromide. Soil solariza-
tion had an advantage in that the nutsedge was
allowed to emerge through the mulch then was
burned off with Gramoxone Extra prior to trans-
planting tomatoes. The soil heating promoted
more of the tubers to germinate early so that the
Gramoxone weakened them and few
nongerminated tubers remained to replace them.
Also, it is believed that Devrinol aided nutsedge
control, even though it is not normally considered
particularly effective against nutsedge. Pigweed
has been observed to be a weed problem with
Tillam on some farms, but it was not in this study.
Control of pigweed was good with both alterna-
tives, although solarization was not quite as good
as the fumigants. Crabgrass continued to be a
problem with solarization, even after including
Devrinol this past fall in order to give solarization
some help with weed control. One explanation for
this may be the degradation of Devrinol over time
and the heating of the soil due to the opacity of the
clear mulch after painting prior to transplanting
tomatoes. Remember that Devrinol was already in
the soil for more than 2 months prior to planting,
thus we were nearing the end of its effective life in
the soil before we even began the crop. Last year
crabgrass did not appear until about midseason,
after what would normally be considered the life
expectancy of residual activity from Devrinol;
however, in 2001 crabgrass was present early and
there was an interaction between fall alternative
treatment and spring cropping practice for the
number of crabgrass plants present in October
(Table 3). As a result, the number of crabgrass
plants in each fall fumigant plot varied as to what
the spring crop had been. Solarization plots con-
tained more crabgrass than the fumigants or the
nonfumigated plots when used following spring
cucumbers, but following either millet or fallow
there was no difference in the number of crabgrass
plants between the nonfumigated and solarization.
Crabgrass numbers were comparable between
methyl bromide and Telone C-17 + Tillam +
Devrinol..
Fusarium wilt, race 3, infected 93% of the
nontreated control plants during the fall of 2001
(Tables 4). The incidence of fusarium wilt was
very low with methyl bromide and Telone C-17
(10 and 13%, respectively), whereas 53% of the
plants growing in solarized soil were infected.
These levels were very similar to what we saw last
year, suggesting that the relationship has matured
and numbers will remain fairly stable over the
coming year. Bacterial wilt and southern blight
were minor pests in this study and there was no
difference in their incidences. There was no effect
of spring cropping practice on fusarium wilt of
tomato in the following fall. This demonstrates
that the spring “crops” do not serve as hosts for
this pest.
Rootknot nematode population levels were
higher in plots treated with fumigants and no
fumigant than they had been during the fall of
2000, but the levels were lower than what was
observed in 2000 with solarization (Tables 5 and
50
6). (What may appear to be errors in these tables
are the result of transformation of data for analysis
but reporting nontransformed data. The letters
indicating the relationship among treatments are
correct.) Rootknot nematode populations did not
increase over time in the soil around the tomato
roots where no fumigant was used because there
were few live roots to support them as most of the
plants had been killed by Fusarium wilt. The most
rootknot nematodes were found associated with
roots grown in soil solarization plots. By the end
of the season, there were no differences among
treatments for the number of rootknot nematodes.
Both fumigants reduced the populations of stunt
and sting nematodes. Stubby root nematodes were
impacted by treatment just prior to first harvest,
but by the end of the season, there were no differ-
ences among treatments. Cyst nematodes have
been observed since early in the life of this study
and the numbers are slowly increasing. Cyst is an
important species and its presence allows the use
of higher than normal rates of Telone products. We
saw little effect of the spring cropping practice on
the pest levels or crop response in fall tomatoes,
with the exception of populations of ring nema-
todes where the least number were observed in
plots planted to millet in the spring and the most
were in those plots where double cropped cucum-
bers were grown. The production on galls on the
roots of tomatoes was greatest with no soil treat-
ment, intermediate with soil solarization and the
lowest with methyl bromide and Telone C-17
(Table 7).
The most important thing in tomato produc-
tion is what you put in the bucket and how it
grades out. Fruit were harvested twice during the
season and were sorted into cull and marketable
categories by hand, then were size graded using a
portable mechanical grader. The sorting criteria
were based on what two growers indicated would
be allowed during fall 2001 so as to assure our
criteria reflected not only the USDA grade stan-
dards, but also the local interpretation of those
standards. Telone C-17 + Tillam + Devrinol
produced as many tomatoes as methyl bromide in
each of the three size categories and total market-
able (Table 8). Production was reduced with soil
solarization + Devrinol compared to methyl bro-
mide or Telone C-17 with solarization falling
between no fumigation and methyl bromide.
Marketable fruit production with solarization was
about one-half of what it was with methyl bromide.
Double cropping is an important part of
tomato production for many growers as it provides
certain economies to the farming operation. Grow-
ers have questioned the future of double cropping
in the absence of methyl bromide. This long term
study also addresses that issue.
Cucumber was grown as a double crop the
following spring for each of the 4 years of this
study. Nutsedge control with Telone C-17 + Tillam
+ Devrinol was not different from that obtained
with methyl bromide, but solarization plots had
fewer nutsedge plants than methyl bromide (Table
9). This most likely was the result of reductions in
the overall tuber supply in the soil by heating the
soil to stimulate tuber sprouting, followed by
repeat applications of Gramoxone Extra to weaken
the plants or kill them. Interestingly the number of
nutsedge plants with methyl bromide were not
different from the nontreated control plot. The
population of crabgrass in cucumber plots was not
affected by fall fumigant practice. Pigweed was
reduced equally well by the two fumigants and
solarization.
Yield of double cropped cucumbers was the
greatest in solarized plots (Table 10). Unlike
previous years, there was no difference in cucum-
ber production between either fumigant and the
nontreated control treatment, while solarization
had significantly higher yields than the nontreated
control. Fall fumigation treatment did not affect
nematode populations with the exception of ring
nematodes which were more abundant where no
fumigant or solarization was used (Table 11).
Spring cropping practice impacted the populations
of several nematode species. Significantly more
rootknot, stubby root and ring nematodes were
present in areas where cucumbers were grown than
with millet or fallow. Stunt nematodes were
favored by fallowing the land.
Because differences in millet growth were
observed, millet tissue samples were collected and
analyzed for macro nutrient content. There were
no differences with the exception of Mg which was
the lowest in plants grown where no fumigant or
51
solarization had been applied over the past 4 years
(Table 12).
The implications of the results of this
project are that Telone C-17 (or Telone C-35)
combined with the appropriate herbicide can be as
effective as methyl bromide against soilborne pests
of tomato and can maintain that level of control in
the absence of methyl bromide. However, the
application of herbicide partners will require
greater attention to detail and selection of proper
application procedures and equipment. Nematode
control with Telone products can be as good as
with methyl bromide. Telone C-17 can control
Fusarium wilt as well as methyl bromide / chlo-
ropicrin mixtures when it is applied in the bed
using the same equipment as methyl bromide.
52
53
54
55
56
57
58
59
60
61
62
63
64
Development and Evaluation of aBiologically-Based System and aChemically-Based Alternative Systemto Methyl Bromide for TomatoProduction in Miami-Dade County.
Waldemar Klassen, Herbert H. Bryan, Robert T.
McMillan, Yuncong, Li, Q. R.Wang, A. Abdul-Baki,
M. Cadallo, Z. A. Handoo, D. Chitwood,
AbstractIn experiments at Homestead, FL tomato
yields in plots on which nematode-resistant cover
crops had been grown were comparable to those
grown on plots fumigated with methyl bromide-
chloropicrin. The cover crops were found to
strongly suppress various taxa of plant parasitic
nematodes and to spare non-parasitic and benefi-
cial taxa of nematodes. When irrigation was regu-
lated to maintain soil moisture tension near 30
cbars, tomato yields were significantly greater than
at 5 cbars. In addition at 30 cbars 70% less water
was consumed than at 5 cbars. KPAM when
injected into raised beds with injection shanks
spaced 8 inches apart suppressed nutsedge, root rot
pathogens and root knot nematodes as well or
better than methyl bromide-chloropicrin. Depend-
ing on KPAM dose, tomato yields in KPAM treated
beds were as great or greater than in MC-33 treated
beds. Automation of irrigation was not performed
because funds came too late, however this will be
done in the 2002-2003 season.
ObjectivesDuring the 2001-2002 winter production season,
conduct two randomized complete block experi-
ments each with four replicates at the Tropical
Research and Education Center:
A. Biologically-based system: identify the
most effective cover crop to be used in the crop/
optimized irrigation/plastic mulch system. Thus
tomato yields with sunn hemp, velvet bean, cow-
pea, sorghum Sudan and bare fallow will be deter-
mined.
B. KPAM system. Demonstrate the proper
use of KPAM, and compare its effectiveness to that
of methyl bromide plus chloropicrin.
C. In both systems, introduce the use of
automatic or switching tensiometers to precisely
control irrigation.
Experiment #1: Cover Crops as Alterna-tives to Methyl Bromide in Fresh MarketTomato Production in South Florida.
Investigators: Bryan, H. H., W. Klassen 5 Q.R.
Wang, A. Abdul-Baki, Y. Li and M. Codallo.
An experiment was conducted at the Tropical
Research and Education Center, University of
Florida, Homestead, to evaluate use of biological
alternatives to methyl bromide (MeBr) in growing
fresh-market tomatoes (Lycopersicon esculentum,
Mill). The biological alternative system consisted
of using ‘Sanibel’, a nematode resistant tomato
cultivar in 2000-2001 and ‘Leila’ a nematode
susceptible cultivar for 2001-2002; the nematode
resistant cover crops [cowpea (Vigna unguiculata
cv. Iron Clay), velvetbean (Mucuna deeringiana)
and sunn hemp (Crotalaria juncea cv. Tropic Sun)
in a cropping rotation. The experimental design
was planned to serve also as a demonstration, and
it employed 230-ft long treatment strips each
containing three raised beds. Samples of ten plants
were randomly selected per rep for yield determi-
nations. There were two cover crop treatments
(cowpea and velvetbean) and a methyl bromide
control treatment in 2000-2001. A third cover crop
treatment using sunn hemp was added in 2001-
2002. Two harvests were made in 2001 and three
in 2001-2002. Harvested fruits were graded fol-
lowing Florida Tomato Committee Standards, and
separated into extra large and total marketable.
The yields (tons/hectare) were as follows:
65
There were no significant differences in extra
large fruits among the MeBr and the cover crop
treatments in 2000-2001. Yields of extra large
fruits were higher in the cowpea and sunn hemp
treatments than in MeBr treatment in 2001-2002.
Total marketable yield in 2000-2001 was highest in
MeBr and lowest in cowpea. Total marketable
yield in 2001-2002 was significantly highest in
cowpea whereas, yields were similar in MeBr,
sunn hemp and velvetbean. In both years, the
percentage of extra-large fruits was very high and
total marketable yields of all treatments were
higher than average yields for South Florida. The
yields in 2001-2002 were affected by substantial
infections of Alternaria and target spot. The cover
crop treatments appear to offer a viable alternative
to MeBr and result in comparable yields at a lower
cost and less environmental hazard than MeBr.
Experiment #2. Influence of cover crops onsoil nematodes in a south Floridatomato field.
Investigators: Q. R. Wang, W. Klassen, Z. A.
Handoo, D. Chitwood, A. Abdul-Baki, H. H. Bryan
and Y. C. Li.
A field experiment was conducted to
evaluate the effects on populations of nematodes in
tomato plots on which three legume cover crops
(sunn hemp, Crotalaria juncea, velvetbean, Mu-
cuna deeringiana, and cowpea, Vigna unguiculata)
had been grown, and some kept as a weed-free
fallow and treated with methyl bromide-chloropi-
crin (MC-33). Sampling during tomato flowering
revealed that weed-free fallow followed by MC-33
strongly suppressed populations of plant-parasitic
nematodes (Helicotylenchus spp., Pratylenchus
spp., Rotylenchulus reniformis, and Quinisulcius
spp.), but some non-plant parasitic nematodes
(dorylaimids and rhabditids) survived. Sunn hemp
strongly suppressed the above-mentioned popula-
tions of the plant-parasitic nematodes, except,
Helicotylenchus spp., and also spared Tylenchus,
dorylaimids, Mononchus, and rhabditids.
Velvetbean strongly suppressed Aphelenchus,
Pratylenchus and Mononchus, but spared
Helicotylenchus spp., and small or moderate
populations of R. reniformis, Quinisulcius,
Tylenchus dorylaimids, and rhabditids. Cowpea
strongly suppressed all nematode taxa except the
rhabditids. By the time that the tomato fruit had
been harvested, the total numbers of nematodes
had increased in all of the treatments, so that the
increase was 852% in the cowpea treatment, 237%
in the weed-free fallow plus MC-33 treatment,
60% in the sunn hemp treatment and 10% in the
velvetbean treatment. In the cowpea treatment
most of the increase occurred in the non-plant
parasitic taxa. In the weed-free fallow plus MC-33
treatment, Aphelenchus and the dorylaimids has
increased the most followed by Helicotylenchus
and Pratylenchus. In the sunn hemp treatment, the
Helicotylenchus density and that of other taxa had
changed little. In the velvetbean treatment the
modest build up of Aphelenchus was the most
notable change. Unfortunately the plots were not
infested with any of the nematodes known to
severely reduce tomato yields in Florida, i.e., root
66
knot (Meloidogyne spp.), sting (Belonolaimus spp.)
and stubby root (Trichodorus spp.) nematodes.
Nevertheless these nematode-resistant cover crops
appear to be promising candidates as replacements
for methyl bromide in tomato production systems.
Experiment #3. Improved Tomato Produc-tion with Summer Cover Crops and Re-duced Irrigation Rates.
Investigators: Wang, Q. R., H. Bryan, A. Abdul-
Baki, W. Klassen, Y. C. Li, and M. Codallo.
To evaluate the effects of various cover
crops and irrigation rates on tomato production in
south Florida, a field experiment was conducted in
2001-2002 with 3 legume cover crops [sunn hemp
(Crotalaria juncea), cowpea (Vigna unguiculata)
and velvet bean (Mucuna deeringiana)], 1 non-
legume cover crop [sorghum Sudangrass (Sorghum
bicolor x S. bicolor)], clean fallow, and 4 irrigation
rates: 5, 10, 20 and 30 cbars. The cover crops were
planted on May 9, 2001. Two months later the sunn
hemp was flail-mowed at 30-cm above the ground
to promote branching, and the cowpea was flail-
mowed at ground level and reseeded. During the
first week of October, 2001 all of the cover crops
were flail-mowed and incorporated into the soil.
Each bed was provided with two drip lines and
covered with W/B plastic mulch. Tomato seedlings
were planted during the 3rd week of October. The
dry weights (Mt/ha) of biomass returned to the soil
were as follows: sunn hemp, 13.7; velvet bean,
11.0; cowpea, 12.0, and sorghum Sudan grass, 5.3.
The corresponding tomato total fruit yields (Mt/ha)
were: 61.3, 59.7, 51.0, 58.9, respectively, and 54.8
from the fallow treatment. The tomato fruit yields
were significantly greater with soil water tension
maintained near 30 than near 5 cbars. Water use
near 30 cbars, was 70% less than near 5 cbars.
Thus the use of sunn hemp and velvet bean and
reduced levels of irrigation can significantly
increase tomato yields and reduce water require-
ments.
Experiment #4. Evaluation of KPAM as anAlternative to methyl bromide inTomato production.
Investigators: R. T. McMillan, Jr., H. H. Bryan, W.
Klassen and M. Codallo.
The experiment was conducted on a tomato
grower’s field just east of Tamiami Airport in Mi-
ami-Dade County. The soil is much sandier than the
Krome gravely loam on which most tomatoes are
produced in Miami-Dade County. The experiment
was laid out as a randomized block replicated four
times. Each treatment consisted of a standard raised
bed 100 feet long and 6-feet wide (center-to-center).
The treatments consisted of an untreated control,
Methyl bromide-chloropicrin (MC-33) at 450 lb./
acre, KPAM at 50 gal/acre, and KPAM at 75 gal/
acre. On February 27 and 28, 2002 the MC-33 was
injected through four shanks 8-inches apart and 6-
inches deep; and the KPAM was injected 4 inches
deep through 6 shanks/bed. Florida 47 tomato seed-
lings were transplanted into the beds on March 16,
2002. The density of nutsedge in the untreated con-
trol was 2.5 plants per foot along the bed and about
40 percent of this density in beds treated with MC-
33 and with the lower rate of KPAM. Most of the
nutsedge plants in KPAM treated beds occurred on
the shoulders of the beds and distant from the pas-
sage of the most lateral injection shank. The yields
were as follows:
67
Immediately following the last harvest, the roots of ten plants in each bed were scored for root rot and root
knot nematode infections. The average scores were as follows:
xscoring was 0 to 5 with 0 was the best control and 5 was the worst.yColumn numbers with the same letter are not significantly different at P=0.05.
68
Manuscripts Prepared:
Bryan, H. H., W. Klassen 5 Q.R. Wang, A. Abdul-
Baki, Y. C. Li and M. Codallo. Cover.
Crops as Alternatives to Methyl Bromide in
Fresh-Market Tomato Production in South
Florida.
5 Wang* , Q. R., W. Klassen, Z. A. Handoo, D.
Chitwood, A. Abdul-Baki, H. H. Bryan and
Y. C. Li. Influence of cover crops on soil
nematodes in a south Florida tomato field.
(Presented at meeting of Soil and Crop
Science Society of Florida).
Wang, Q. R., H. Bryan, A. Abdul-Baki, W.
Klassen, Y. C. Li, and M. Codallo. Im-
proved Tomato Production with Summer
Cover Crops and Reduced Irrigation Rates
(Presented at meeting of Florida State
Horticultural Society).
Wang, Q. R., Y. C. Li* , and W. Klassen. Changes
of soil microbial biomass carbon and
nitrogen with cover crops and irrigation in
a vegetable field. Plant and Soil (submit-
ted).
69
Breeding Tomatoes for Florida
J. W. Scott
Gulf Coast Research & Education Center
University of Florida
5007 60th Street East
Bradenton, Fl 34203
AbstractSeveral hybrids are being considered for
release and are available for grower testing. These
include; Fla. 7973-fusarium race 3 resistant but
also for general use, Fla. 7964-spotted wilt resis-
tant, NC 99405 (HMX 1803)- heat tolerant,
jointless, fusarium wilt race 3 resistant, Fla. 7810
fusarium crown rot resistant, Fla. 7885B strong
heat-tolerance, Fla. 7943-fusarium wilt race 3
resistant and heat-tolerant, Fla. 7816-heat-tolerant,
and Fla. 7926-heat-tolerant. Outstanding inbreds
presently being used as parents include Fla. 8044-a
high lycopene line with superior heat-tolerance,
new fusarium crown rot resistant inbreds with high
lycopene (used in F1’s 8084 and 8085 now in
limited grower trials), and a new spotted wilt
resistant inbred. Fla. 8109 is a bacterial wilt resis-
tant line with large fruit and could represent a
break in a linkage of resistance to smaller fruit
size. Geminivirus resistance breeding is progress-
ing well, but it will be a few years before hybrids
are ready for advanced and grower testing. Fla.
8059 is an inbred that has a high level of firmness
and other good characteristics including high
lycopene and flavor. It may have some commercial
applications in the near future in competing with
cluster tomatoes in the market. Compact growth
habit hybrid Fla. 8107 performed well at GCREC
and TREC and will be tested on grower farms as a
prototype for stake-less production.
IntroductionImproved varieties are needed to keep the
Florida tomato industry competitive in a changing
world. Improvements include the areas of yield,
pest resistance, and fruit quality. Florida’s geogra-
phy offers many challenges for tomato improve-
ment, since high temperatures limit fruit set and
are conducive to disease and insect problems.
There are no neighboring states with similar
latitudes to most of Florida, so there is less help in
solving agricultural problems than is the case in
many states. Although private companies have
tomato breeding programs that develop varieties
for Florida, these companies are not set up to
handle many of the long term, high risk projects
that could prove valuable in the future. The Uni-
versity of Florida tomato breeding program aims at
such projects and works in partnership with the
private companies to deliver improved varieties of
benefit to the Florida tomato industry. Much of
the groundwork for the development of heat-
tolerant varieties was done at the University of
Florida (Scott et al., 1986). ‘Solar Set’ has been an
important commercial, heat-tolerant variety for 11
years after it’s release (Scott et al., 1989). We now
have Fusarium wilt race 3 resistant varieties using
a resistance gene discovered in a wild species by
this program in the 1980’s (Scott and Jones, 1989).
Breeding lines with Fusarium crown and root rot
resistance have recently been released (Scott and
Jones, 2000) and varieties ought to be available in
a few years. With the impending loss of methyl
bromide, these pathogens could become more
widespread. Other diseases such as bacterial wilt
and spotted wilt occur in Florida, but cause far
more damage in other regions of the world. If
something changes and these diseases become
more prevalent, Florida would benefit from resis-
tant varieties. Geminiviruses like tomato mottle
(ToMoV) and tomato yellow leaf curl virus
(TYLCV) pose a threat to Florida tomato produc-
tion. Other regions have these or other
geminivruses (Polston and Anderson,1997). A
project has been ongoing since 1990 utilizing
resistance genes from a wild species. It appears
that four genes have been introgressed, and these
genes may well be useful in solving the long term
geminivirus problems that Florida will likely face.
Tomatoes have met with considerable dissatisfac-
tion in the marketplace. Essentially, this relates to
compromises that are made in providing fruit that
will ship well. Solutions to this problem are not
simple. Research is needed to provide tomatoes
that will be more acceptable to consumers. On the
bright side, recent medical literature has shown
70
that lycopene, the red pigment in tomato, has
strong antioxidant properties that reduce several
cancers. Work in the breeding program has been
ongoing for 18 years with a crimson gene (ogc) that
improves internal tomato color and increases
lycopene by 50%. Crimson varieties could be a
boon to the Florida industry in the not too distant
future. Genetic alteration of plant architecture
might provide varieties for mechanical harvest or
reduced costs in manual labor and equipment. This
could be critical for future production in Florida.
This is another long-term, high risk project that is
being pursued in my program that is not likely to
be attempted by the private sector. Funding of the
Florida Tomato Committee has been imperative to
the operation of this breeding program, an invest-
ment that has and will continue to pay dividends.
Objectives of this project were:
1) To develop varieties or breeding
lines resistant to soil borne
pathogens.
2) To develop improved heat-tolerant
inbreds and hybrids.
3) To develop commercially accept-
able breeding lines and hybrids
resistant to geminiviruses or spotted
wilt virus.
4) To improve fruit quality and
postharvest characteristics.
5) To develop commercial hybrids for
the Florida tomato industry.
Objective 1
MethodsThere were 74, 65, and 11 lines screened
for Fusarium wilt race 3 in fall 2001, spring 2002,
and summer 2002, respectively. Twenty-two F1’s
were evaluated for the first time. There were 44,
61, and 7 lines screened for Fusarium crown rot in
fall 2001, spring 2002, and summer 2002, respec-
tively. There were 16 and 71 lines inoculated with
the bacterial wilt pathogen and evaluated in spring
and summer 2002, respectively. In spring 2002, a
yield trial comparing advanced inbreds was con-
ducted that included 5 lines resistant to race 3 and
1 line resistant to fusarium crown rot. Several
hybrids with resistance to race 3 or crown rot were
evaluated in state -wide and observation trials in
fall 2001 and spring 2002. Seven bacterial wilt
resistant inbreds are being tested for resistance and
fruit size in a replicated trial where they are being
compared to control lines. All were inoculated with
the bacterial wilt pathogen.
ResultsFla. 7946, a Fusarium wilt race 3 resistant
inbred, has continued to perform well as it did the
previous year. It was crossed with NC 84173 to
make hybrid Fla. 7973. This hybrid has performed
well consistently in 2001 and 2002. It does not
have heat-tolerance so is not recommended in early
fall crops but should be considered in all other
growing seasons even if race 3 is not a problem. It
will likely be released in fall 2002. Fla. 7810 is
heat-tolerant and resistant to fusarium crown and
root rot. It has done consistently well in observa-
tion trials over several years and is now being
tested in replicated and grower trials. Two inbreds
with race 3 resistance are in Syngenta hybrids that
are soon to be released. These hybrids have resis-
tance to fusarium crown rot as well which comes
from the Syngenta side of the cross. Hybrids with
crown rot resistance are also being made using
some outstanding inbreds that have been developed
using Fla. 7781, a breeding line release from 1999
and a line from North Carolina. Fla. 8109 is a
bacterial wilt line that has large fruit with resis-
tance similar to Hawaii 7997, the small fruited
source of resistance. Apparently a linkage between
resistance and small fruit size has been broken.
This could bring on a new era in developing
bacterial wilt resistant varieties because up to now
it has not been possible to develop large fruited
varieties with a high level of resistance.
Objective 2
MethodsHeat-tolerant (HT) fruit setting ability is
being incorporated into all phases of the breeding
program. In spring 2002, 25 HT inbreds were
evaluated for their performance under non-heat
stress conditions. In summer 2002, 94 HT lines are
71
being evaluated under high temperature conditions.
There were 47 crosses with HT recurrent parents
made in fall 2001 and spring 2002. In the spring
2002 yield trial mentioned under Objective 1, 7 of
the lines tested were experimental HT lines. In
summer 2001, a yield trial was conducted to
evaluate HT inbreds and hybrids. Numerous HT
hybrids were tested in fall and spring replicated or
observation trials. Seven HT lines are being tested
in the same replicated trial mentioned under the
bacterial spot project for summer 2002.
ResultsFla. 7885B has two heat-tolerant parents
and is a week earlier than other heat-tolerant
hybrids under high temperature growing condi-
tions. It has smooth fruit and performs well during
all growing seasons in Florida. It also has excep-
tional vine cover. It is being considered for release
by testing in state-wide and grower trials.
NC99405, a jointless ,heat-tolerant, fusarium wilt
race 3 resistant hybrid has tested well in replicated
and grower trials, but the fruit may not hold firm-
ness after table ripe as much as desired and this
could preclude release. Growers should test this
experimental hybrid under their conditions. In
general, fruit set was not good in summer 2001 in
that lines that generally set well did not. However,
a new line Fla. 8044 had exceptional fruit set. Fruit
had good size, firmness, smoothness, and internal
color due to the crimson gene. In spring 2002, Fla.
8044 was a week earlier that all other large fruited
lines or hybrids. It had significantly greater yield
than all other genotypes tested and fruit size was
comparable to ‘Florida 47’. Hybrids were made
with 8044 and it is anticipated that one or more
will be released rather soon. Such a hybrid should
provide growers with a more reliable yielding
variety that those presently available and thus
should have a major impact on the Florida variety
picture.
Objective 3
MethodsThere were 331 and 309 lines inoculated
separately with ToMoV and TYLCV, rated for
disease severity, and evaluated for horticultural
type in fall 2001 and spring 2002, respectively.
There were 50 and 115 hybrids with a ToMoV
resistant parent that were evaluated in fall 2001
and spring 2002, respectively. Some of the most
resistant lines with better horticultural characteris-
tics were tested in replicated trials that were inocu-
lated separately with ToMoV and TYLCV in
spring 2002. These trials allow for statistical
comparisons of the lines which helps to determine
the best resistance sources.
There were 44 and 50 inbreds with spotted
wilt resistance evaluated in fall 2001 and spring
2002, respectively. There were 38 and 18 hybrids
made in fall 2001 and spring 2002, respectively.
There were 6 spotted wilt resistant hybrids evalu-
ated in the spring at GCREC. Fifteen hybrids and
9 inbreds (using a different resistance source) were
evaluated in an experiment at NFREC. Selection
for resistance is done with sequence characterized
amplified region (SCAR) molecular markers that
eliminate the need to screen with thrips and poten-
tially spread the virus in the west coast growing
region.
ResultsThere were 255 geminivirus resistant
selections made in the fall and 50 F1’s were ad-
vanced. In spring 2002, 230 selections were made
and 47 F1’s were advanced. Most lines now have
determinate plant habits and good fruit set. A few
inbreds appear to be near the horticultural at-
tributes needed to make commercial hybrids.
Resistance will have to be bred into both parents of
a hybrid variety to insure the best resistance level,
since inheritance is primarily additive. The ToMoV
and TYLCV replicated trials and breeding plots
indicated that almost all of the lines resistant to
ToMoV were also resistant to TYLCV. Several
lines had greater TYLCV and ToMoV resistance
than PX 150535. Progress was made in locating
molecular markers closely linked to the resistance
genes but this work is not complete yet. Good
molecular markers would speed up the breeding
process. With or without the markers, it is antici-
pated that experimental hybrids will be available
for grower testing within the next 2 years.
Fla. 7964 has performed the best of the
72
spotted wilt resistant hybrids being trialed. It
looked good in North Carolina in summer 2001
and has been comparable to other spotted wilt
resistant hybrids in replicated trials at GCREC and
NFREC in fall 2001 and spring 2002. Some
spotted wilt resistant inbreds have shown improve-
ment over existing lines as hybrid parents. These
hybrids are ready for more advanced testing.
Spotted wilt resistance is important to Tomato
Committee members who grow in North Florida or
elsewhere in the southeastern US at present. It will
also be important if this disease becomes more
serious in the peninsula of Florida.
Objective 4
MethodsFruit quality and shelf-life are emphasized
in all breeding projects. One method to improve
shelf-life is to develop varieties with a high level
of firmness that we call ultrafirmness. Another
method is to incorporate the ripening inhibitor (rin)
gene in firm genetic backgrounds and make
heterozygous rin hybrids. In fall 2001, 28 ultrafirm
(UF) inbreds were evaluated. In spring 2002, 18
UF lines, 21 UF F1’s, and 22 rin hybrids were
evaluated.
Another aspect of fruit quality is the devel-
opment of high lycopene varieties by using the
crimson (ogc) gene. This gene is widely distributed
in the various breeding projects. New hybrids are
continually being made and evaluated.
There were 64 and 62 lines evaluated
primarily for improved flavor in fall 2001 and
spring 2002, respectively. High sugars are also
being incorporated from cherry sized lines to large
fruited lines for flavor improvement. In fall 2001,
56 high sugar hybrids were made and 29 lines were
evaluated for sugars in fall 2001 and spring 2002.
The most interesting lines from all flavor work are
put in flavor trials described in the grant report
with Dr. Elizabeth Baldwin.
Another project is to develop tomatoes that
do not require staking by use of the brachytic (br)
gene that reduces plant height and increases side
shoots. These tomatoes are called compact growth
habit (CGH) tomatoes. Many are very firm. In fall
2001, 38 CGH lines were evaluated, 21 F1’s were
advanced, and 19 hybrids were made. There were
28 CGH lines evaluated in spring 2002 and 59 F1’s
were evaluated and advanced to F2. In winter 2002,
40 CGH lines were evaluated in at TREC.
ResultsIt has been difficult to obtain UF lines with
good flavor characteristics, but there do seem to be
a few lines with good flavor based on data over
two years. Fla. 8059 is such a line and it is pres-
ently being tested in a replicated trial to verify it’s
firmness and flavor. Flavor is also emphasized in
the rin project since rin/+ hybrids often have poor
taste. For this reason there was less work done with
rin this year. After considerable trials over many
seasons, it appears that crimson lines often have
good flavor, but are not high in acidity. This can
result in a somewhat bland flavor under some
conditions. Recent work has emphasized crimson
lines with greater acidity to overcome this prob-
lem. Twenty-one F2’s and 14 F
3’s were evaluated in
fall 2001 and spring 2002, respectively to improve
ogc acidity. New crimson hybrids are evaluated
each season and compared to existing ones that
have done well in the past such as Fla. 7862 and
Fla. 7945.
Fla. 8107 is a CGH hybrid that performed
well at TREC and GCREC in 2002. This hybrid
will be used as a prototype for stake-less tomato
production in Homestead in sequential plantings
during the 2002-2003 season. Emphasis is being
placed on jointless lines that could result in ma-
chine harvest varieties, but these are not as ad-
vanced horticulturally.
Objective 5
MethodsHybrids are evaluated for horticultural type
in breeding plots each season with two replicates
for those that are expected to have commercial
potential. After the initial evaluation, those selected
for further testing are put in observation trials at
GCREC and NFREC, with some also being tested
at TREC. Those that perform well in the observa-
tion trials are tested in state replicated trials (at the
73
3 above centers and IRREC) and in trials on
growers farms. For seed production, it is hoped
that the initial crossing produces enough seed for
the first two evaluations. When a hybrid moves
onto the advanced trial phase more seed is pro-
duced.
ResultsExperimental hybrids being seriously
considered for release include Fla. 7973, Fla. 7810,
Fla 7885B, NC 99405, and Fla. 7964, mentioned
previously. Others include Fla. 7943 a heat-tolerant
fusarium wilt race 3 hybrid, heat-tolerant hybrids
Fla. 7926 Fla. 7816, and Fla.7978, and compact
growth habit hybrid Fla. 8107. Many others are in
the second phase of testing and some of these will
be available for grower tests in 2003.
Literature Cited
Polston, J. E. and P. K. Anderson. 1997. The emer-
gence of whitefly-transmitted geminiviruses
in tomato in the Western Hemisphere. Plant
Dis. 81: 1358-1369.
Scott, J. W., and J. P. Jones. 1989. Monogenic resis-
tance in tomato to Fusarium oxysporum f. sp.
lycopersici race 3. Euphytica 40:49-53.
Scott, J. W., and John Paul Jones. 1995. Fla. 7547
and Fla. 7481 tomato breeding lines resistant
to Fusarium oxysporum f. sp. lycopersici
races 1,2, and 3. HortScience 30(3):645-646.
Scott, J. W., and John Paul Jones. 2000. Fla. 7775
and Fla. 7781: Tomato breeding lines resis-
tant to Fusarium crown and root rot.
HortScience 35(6):1183-1184.
Scott, J. W., S. M. Olson, J. J. Bryan, T. K. Howe, P.
J. Stoffella, and J. A. Bartz. 1989. Solar Set:
A heat tolerant, fresh market tomato hybrid.
Fla. Agric. Expt. Sta. Circ. S-359 10p.
Scott, J. W., R. B. Volin, H. H. Bryan, and S. M.
Olson. 1986. Use of hybrids to develop heat
tolerant tomato cultivars. Proc. Fla. State
Hort. Soc. 99:311-314.
74
Breeding Tomatoes for Resistance toall Three Races of the BacterialSpot Pathogen
J. W. Scott
Gulf Coast Research & Education Center
University of Florida
5007 60th Street East
Bradenton, FL 34203
J. B. Jones
Plant Pathology Department
University of Florida
Gainesville, FL 23611
AbstractThree of four races of the bacterial spot
pathogen that infect tomato are in Florida with race
T3 being the most important. Resistance to race T3
has been incorporated into improved heat-tolerant
breeding lines and some of these should be accept-
able as parents to make commercial hybrids.
Testing of hybrids in summer 2001 was not opti-
mal because plants did not grow well due to fertil-
izer leaching. Most hybrids tested in spring 2002
were not up to commercial standards, but a few
were better and are presently being retested along
with about 62 new hybrids. Inbreds with T3 or T3
plus T1 resistance are being evaluated for resis-
tance and horticultural type this summer. Lines
with broad spectrum resistance derived from PI
114490 are also being developed with a small
number having potential as parent lines. Separate
genes were found to control T2 and T3 resistance
from PI 114490.
IntroductionBacterial spot is still the most ubiquitous
disease problem of tomatoes in Florida. Four
tomato races of Xanthomonas campestris pv.
vesicatoria (Xcv), causal agent of bacterial spot,
have been discovered to date (Astua-Monge et al.,
2000; Jones et al., 1995). In Florida, there are
three races, the original race (T1), the race discov-
ered in 1991 (T3) (Jones et al., 1995), and a new
race (T4)(Astua-Monge et al., 2000). Race T3 has
largely replaced race T1 in Florida (Jones et al.,
1998). Race T4 has mutated from T3 and has been
found in Dade and Manatee counties. It is not
known how important this race is now or might
become should race T3 tolerant varieties be com-
mercially grown. Race T2 was originally reported
from Brazil, but has now been isolated in some
states in the USA including Ohio.
Our breeding project began in 1983 when
we found Hawaii 7998 was resistant to race T1
(Jones and Scott, 1986). More recently resistance
to race T3 was discovered in several accessions
including Hawaii 7981 (Scott et al., 1995), and this
resistance has been incorporated into advanced T1
resistant breeding lines. Lines with resistance to
T1 and T3 also had tolerance to race T2, whereas
lines with resistance to either race alone were
susceptible to T2. This suggests combining bacte-
rial resistance genes in a line may have unexpected
beneficial effects against other bacterial races. We
found PI 114490 was resistant to race T2 in the
summers of 1995 and 1996 (Scott et al., 1997) and
this was further verified from 1997 through 2001 at
Wooster, Ohio. PI 114490 also was resistant to
race T1 and tolerant to race T3. It is not known if
PI 114490 has resistance to race T4. The general
T2 resistance from PI 114490 needs to be incorpo-
rated into advanced breeding lines. This general
resistance could be important should race T2
migrate into Florida. The use of varieties with
such resistance might also protect against any new
race which might emerge in the future. The objec-
tives of this research were:
1) To develop commercial hybrids with
tolerance to bacterial spot races T3 and
T1.
2) To incorporate general Xcv resistance
from PI 114490 into advanced breed-
ing lines.
3) To combine new T2 resistance genes
with known resistance genes.
Objective 1
MethodsIn summer 2001, 154 breeding lines (F
2 and
more inbred) and 67 hybrids with resistance were
inoculated with race T3 and evaluated in the field.
Nine hybrids were evaluated in the fall. Also in the
75
fall, 2 hybrids heterozygous for bacterial spot
resistance were evaluated in advanced observa-
tional trials at NFREC. Some of the hybrids were
evaluated for commercial potential and some were
made to recombine traits from two resistant par-
ents. In spring 2002, 43 F1’s with some resistance
to races T1 and T3 were evaluated in breeding
plots and 21 of these were also evaluated in a yield
trial. Additionally, 11 inbreds were evaluated in
breeding plots and 5 inbreds were evaluated in a
yield trial for horticultural type in the spring. At
Homestead (TREC), 30 lines with bacterial spot
resistance were evaluated in winter 2002. In
summer 2002, 130 breeding lines (F2 and beyond)
are being evaluated that have T3, or T3 and T1
resistance. Also this summer, 68 F1’s are being
evaluated. Two inbreds and 1 hybrid are being
evaluated in replicated trials this summer.
ResultsIn summer 2001, 43 selections were made
for lines with race T1 and T3 resistance and 30
lines were selected with only T3 resistance. There
were 27 selections with T1 and T3 resistance
combined with resistance from PI 114490. In
spring 2002, 22 selections were made and 11 F1’s
were advanced to the F2 generation. At Home-
stead, 17 selections were made with T1 and T3
resistance. Many resistant inbreds are too small
fruited to be used as parents in commercial hy-
brids. However, some inbreds appear to have
potential as parents and these are in hybrids being
tested at present. It was difficult to evaluate the
hybrids tested in summer 2001 because fertilizer
had leached out of the beds and the plant growth
was not good. To further complicate matters, notes
taken on a field computer were lost in a computer
mishap. Overall, the hybrids tested in spring 2002
were disappointing, although some were consid-
ered worthy of continued trialing including the 1 in
the yield trial. Critical testing of hybrids is pres-
ently taking place and hopefully accurate assess-
ments will be made. Any hybrids showing potential
will be widely tested in 2003 in University and
grower trials with a release made as soon as fea-
sible if results are good.
Objective 2
MethodsIn summer 2001, 157 breeding lines with
resistance from PI 114490 were evaluated in
Bradenton. Also, an experiment was conducted
testing 85 linbred backcross lines for resistance to
races T2 in Ohio and T3 in Bradenton. In Winter
2002 1 of the bacterial spot resistant lines men-
tioned in objective 1 had resistance from Hawaiian
sources combined with PI 114490. In summer
2002, 104 inbreds with PI 114490 resistance are
being evaluated for T3 resistance. Two inbreds
with combined Hawaiian and PI 114490 resistance,
and 1 inbred with only PI 114490 resistance are
being tested in a yield trial.
ResultsThere were 72 selections made in summer
2001. In general, we have found that resistance
from PI 114490 is very effective for races T1 and
T2 and less effective for T3. The segregation of
inbreds from the inbred backcross populations
indicated that different genes confer resistance to
race T2 and T3 (Scott et al., in press). A few
inbreds are looking good horticulturally and these
are being tested in the yield trial. The best lines of
those being tested this summer will be tested for
T1 and T2 resistance in Ohio next year. They will
also be tested for T4 in Gainesville greenhouse
tests. Emphasis will be placed on lines with broad
based bacterial resistance.
Objective 3
MethodsPreviously, resistance was found in LA
1682 and LA 1684. Crosses were made between
these two accessions and LA 442 and PI 114490,
respectively. The leaf dip test was used on F2’s
from these crosses and selections were made for
improved resistance. Seed from these selections
have been planted in Summer 2002 and they will
be tested for resistance to T3 in the field.
ResultsThe lines are presently being tested and
results are not available at this time.
76
Literature Cited
Astua-Monge, G., G.V. Minsavage, R.E. Stall,
Eduardo C. Vallejos, M.J. Davis, and J. B.
Jones. 2000. Xv4-avrxv4: A new gene -for-
gene interaction identified between
Xanthomonas campestris pv. vesicatoria race
T3 and the wild tomato relative Lycopersicon
pennellii. Molecular Plant-Microbe Interac-
tions 13(12):1346-1355.
Jones, J.B., H. Bouzar, G. C. Somodi, R.E. Stall, K.
Pernezny, G. El-Morsy, and J.W. Scott. 1998.
Evidence for the preemptive nature of tomato
race 3 of Xanthomonas campestris pv.
vesicatoria. In Florida. Phytopathology.
88:33-38.
Jones, J.B. and J.W. Scott. 1986. Hypersensitive re-
sponse in tomato to Xanthomonas campestris
pv. vesicatoria. Plant Dis. 70:337-339.
Jones, J.B., R.E. Stall, J.W. Scott, G.C. Somodi, H.
Bouzar, and N.C. Hodge. 1995. A third to-
mato race of Xanthomonas campestris pv.
vesicatoria. Plant Dis. 79:395-398.
Scott, J.W., J.B. Jones, G.C. Somodi, and R.E. Stall.
1995. Screening tomato accessions for resis-
tance to Xanthomonas campestris pv.
vesicatoria, race T3. HortScience 30:579-
581.
Scott, J. W., S. A. Miller, R. E. Stall, J. B. Jones, G.
C. Somodi, V. Barbosa, D. L . Francis, and
F. Sahin. 1997. Resistance to Race T2 of
the bacterial spot pathogen in tomato.
HortScience 32(4):724-727.
77
Selection of Tomato Lines forCommercial Markets That Exhibit aFruity/Floral Flavor Character Within aBalance Sugar, Acid and Volatile Profile
Elizabeth A. Baldwin
USDA/ARS Citrus & Subtropical
Products Laboratory
Winter Haven, FL
J.W. Scott
University of Florida Gulf Coast
Research & Education Center
Bradenton, FL
AbstractTomato fruit were grown in statistical plots
and the University of Florida Gulf Coast Research
and Education Center. Fruit were analyzed by
sensory panels for flavor rating (consumer panel),
flavor descriptors (trained panel) and chemical
components including color, lycopene, sugars,
acids, and aroma volatiles. Cultivars that had been
fixed over several seasons for an optimum sugar/
acid balance and a fruity/floral character were rated
high by a consumer panel and were found to be
high in sugars, acids and aroma compounds. The
spiking study showed certain volatiles were associ-
ated with specific flavor descriptors.
IntroductionThe tomato industry is facing serious
economic pressures from “vine-ripe” imports from
Mexico and greenhouse-grown fruit from Canada
and Europe. Consumers are obviously willing to
pay a high price for a quality product as evidenced
by the cost of specialty tomatoes (cluster tomatoes,
hydroponically-grown fruit, etc.) displayed in the
supermarket. The industry would gain market
share if a premium tomato product, that combined
the health benefits of high lycopene and improved
flavor quality, were developed.
In this study, We continued to look at
cultivars developed from high lycopene back-
grounds with good horticultural characteristics and
a fruity/floral flavor note that would differentiate a
potential release from the rest of the fresh tomato
market. High lycopene tomatoes may garner
health benefits due to the anti-oxidant, anti-cancer
activity of lycopene (Nguyen and Schwartz, 1999).
Furthermore, the lycopene pigment is responsible
for the red color of tomatoes, and serves as a
precursor for important flavor compounds (Buttery
and Ling, 1993; Buttery et al., 1999). This means
that high lycopene cultivars may result in healthier,
better flavored, and more attractive tomatoes.
MethodsTomato (Lycopersicon esculentum Mill.)
cultivars were grown in a completely randomized
block design with three blocks and ten plants per
plot at the University of Florida Gulf Coast Re-
search and Education Center in Bradenton in fall
and spring of 2001 and 2002, respectively. Culti-
vars, were sampled in the field from three blocks,
and informally evaluated for flavor by the breeder
and one technician. From this screening, cultivars
were selected for sensory and instrumental/chemi-
cal analysis to represent a range in flavor for
comparison to lines that have been fixed over
several seasons for specific fruity/floral flavor
notes with a high lycopene background.
Tomatoes were analyzed by an experienced
panel of 30+ panelists who sampled tomato
wedges representing at least 5 fruit per cultivar.
Sub samples were taken 3 times during the panel
session and analyzed for color and flavor compo-
nents by measurement of solids, sugars, acids and
aroma compounds by refractometer, HPLC, titra-
tion, and gas chromatography (GC) (Baldwin et al.,
1998). Color and pigment analyses were done on
tomato homogenate using a Minolta chromameter
and a scanning spectrophotometer at 450-650 nm
which is the range of absorption spectra for lyco-
pene. For the trained panel, 6-8 members sampled
bland tomato homogenate from the fall season
spiked with food grade aroma compounds.
ResultsConsumer panel data confirmed the assess-
ment of the cultivars by the breeder (Table 1).
Three lines were rated high for overall flavor
including 404, 418, and 420. Cultivars 404, 418
and 420 also were rated high in sweetness along
with 406; and 404 and 418 were rated high in
78
acidity along with ‘Solar Set’. For chemical analy-
sis, 404 and 418 were highest in soluble solids
(SS); 404 and 418 were highest also in total sugars
along with 423; and 404 and 418 were highest in
sucrose equivalents (SE, a measure of sweetness
based on actual sugar levels) and 420 was highest
in SS/TA. Cultivars 404 and 418 were highest in
titratable acidity (TA); (Fig. 1). Cultivars 404,
418, and to a lesser extend 420 were high in alde-
hydes, many ketones, alcohols, isobuthylthiazole
and 2-nitro-phenylethane (particularly cultivar 418
that was selected for the fruity/floral note) (Fig. 2).
Cultivar 406 was also high in many volatiles and in
lycopene (Fig.1), as it has the crimson (ogc) gene.
Conversely, cultivar 424 (bland according to
breeder) was rated low in sweetness, acidity, and
flavor; and was low in SS, sugars, TA and all
volatiles.
Trained panel was used to determine the flavorimpact of individual food grade aroma volatilesthat were spiked into bland tomato homogenate.The main aromas were grouped into “green/grassy”, “fruit”, “floral”, “earthy” and “musty”;
which related to certain groups of aroma com-pounds (Table 2). It was found that spiking blandtomato homogenate with certain aroma compoundsaffected panelist perception of sweetness andsourness, even though sugar and acid levels werenot changed.
79
In conclusion, selection of high flavoredlines, and especially those with a fruity floral notein a balanced sugar/acid background continued.The goal is to obtain a variety stable for this flavorprofile in order to develop a consistent premiumtomato for release to Florida growers.
Literature Cited
Baldwin, E. A., J.W. Scott, M.A. Einstein, T.M.M.
Malundo, B.T. Carr, and R.L. Shewfelt, and
K.S. Tandon. 1998. Relationship between sensory
and instrumental analysis for tomato flavor.
J. Amer. Soc. Hort. Sci. 123: 906-915.
Buttery, R.G. and L. Ling. 1993b. Volatile com-
ponents of tomato fruit and plant parts:
Relationship and biogenesis, p. 22-34. In:
R. Teranishi, R.G. Buttery, and H.
Sugisawa (eds.). Bioactive
Volatile Compounds from Plants. Amer.
Chem. Soc., Washington, DC.
Buttery , R.G., R. Teranishi, R.A. Flath, and L.C.
Ling. 1989. Fresh tomato volatiles:
Composition and Sensory Studies, p. 213-
222. In: R. Teranishi, R.G. Buttery, and F.
Shahidi, (eds.). Flavor Chemistry, Trends
and Developments. American Chemical
Society, Washington, DC.
Nguyen, M.L. and S.J. Schwartz. 1999. Lyco-
pene: Chemical and biological properties,
Food Technol. 53(2): 38-45.
Figure Legends
Fig. 1 Color (hue [H] angle), lycopene, titratable
acidity (TA), percentage soluble solids (%SS), SS/
TA ratio, total sugars, and sucrose equivalents (SE)
for tomato lines grown at Bradenton, Florida in
spring, 2002. For line descriptors see Table 1.
Fig. 2 Volatile aldehydes (A), ketones (B), alcohols
(C), and miscellaneous (D) for spring 2002 tomato
lines, see Table 1 for line descriptors.
80
81
82
83
Mining gold in Florida: Feasibility oflycopene and novel by-productsrecoveries from cull tomatoes via post-harvest manipulations, dehydration andCO2 super critical extraction
Amy Simonne1, Bala Rathinasabapathi2,
Stephen T. Talcott3, Steven A. Sargent4, Jeff
Brecht4, Murat Balaban5, and Maurice R.
Marshall5. 1Assistant Professor, Department of
Family, Youth and Community Science, Institute of
Food and Agricultural Sciences, University of
Florida, P.O. Box 110310, Tel: 352-392-1895, Fax:
352-392-8196, email: [email protected]
(Main contact), 2Assistant Professor, Department
of Horticultural Sciences, 3Assistant Professor,
Department of Food Science and Human Nutrition,4 Professor, Department of Horticultural Sciences,5 Professors, Department of Food Science and
Human Nutrition
Collaborators:Teresa Olczyk, M.S., Extension Agent II. Dade
County (District V)
Eugene (Gene) McAvoy, M.S., Extension Agent II.
Hendry County (District V)
Phyllis R. Gilreath, Ph.D., Extension Agent IV.
Manatee County (District IV)
Joshua Mayfield, M.S. Extension Agent I. Gadsden
County (District I)
AbstractCull tomatoes, from green through pink
stages, can be successfully ripened over a 10-day
period. Green tomatoes ripened to red-ripe stage
during 10 days of gassing, and tomatoes that were
initially pink did not become excessively over-ripe
during this period of time. For ripening of cull
tomatoes to be feasible under packinghouse condi-
tions, there must be little additional labor required
to prepare the tomatoes for ripening and subse-
quent operations. For this reason the cull tomatoes
were carefully sorted by the defect categories.
The results show that the culls must be
sorted (prior to gassing for green fruit). In fact,
only tomatoes that were free of minor defects (i.e.,
“sound” category) ripened without decay (see
Table 4). Green tomatoes with catface had only
6.3% decay and possibly could be included. How-
ever, green and pink tomatoes with cuts and
growth cracks had from 17.0% to 39.6% decay by
Day 10.
The number of culls that were considered
sound was about 20% of the total, based on 33%
sound green and pink tomatoes out of 62.9%
usable tomatoes (see Table 2). An additional 6% of
cull green tomatoes had minor catface (10% of
62.9%) and could also be included. Thus, for a
typical random sample of cull tomatoes, about 39%
of them would be suitable for lycopene extraction.
We have investigated whether culled toma-
toes of the popular cultivar FL-47 can be used as a
source of the red pigment lycopene. We found that
stage 4 “sound fruits” and “culled fruits with cracks”
developed significantly more lycopene in their fruit
walls than fruits with other defects such as cuts and
catface (200 to 300 mg per g versus 100 to 140 mg
per g). A standard ethylene treatment (100 ppm, at
20 EC for 10 days) significantly elevated the lyco-
pene levels in some categories of fruit and not in oth-
ers. Outer tissues, which contributed 10 to 15% of
the total fruit weight, had about three-fold more ly-
copene than the rest of the fruit tissue on a fresh
weight basis (100 to 300 mg per g versus 30 to 80
mg per g).
Our results suggest that (1) culled tomatoes
with various defects can be pooled together and ex-
posed to ethylene for lycopene accumulation. And
(2) there is potential to extract about 200 mg lyco-
pene from every kilogram of outer tissue and about
50 mg lycopene from every kilogram of other fruit
tissue. Based on our preliminary run, it is possible to
extract lycopene from cull tomato tissues by CO2
supercritical fluid extraction. However, additional
studies are needed to manipulate samples and ex-
traction parameters, to obtain the best recovery of
lycopene.
No difference in phytochemical concentra-
tions or antioxidant capacity was found due to ethyl-
ene exposure, and no appreciable difference was
found due to preharvest selection of fruit (see Table
6.). However, outer tissue layers generally had higher
levels of total soluble phenolics (Folins) and fla-
vonoid glycosides that related to higher ORAC val-
84
ues. Levels of hydroxybenzoic and hydroxycinnamic
acids were not different between tissues.
Objective 1To explore the feasibility and possibility of
recovering lycopene and phenolic compounds from
cull or non- marketable tomatoes grown in Florida
using CO2 supercritical extraction (Amy Simonne,
Murat Balaban, Maurice R. Marshall, Stephen T.
Talcott and Mathew Lecky).
Materials & Methods
Supercritical CO2 Extraction of Tomato:An initial run of the supercritical CO
2 extrac-
tion unit (Picture Plate I- 1) was completed in mid
July 2002 after a pump (see Picture Plate I-2) was
purchased and installed. For each run, two kilograms
(5 pounds) of tomato were sliced into pieces (Pic-
ture Plate I-4,5) and were dried to about 50% of the
original moisture in a vacuum oven. The semi-dried
samples (Picture Plate I-6) were then placed in a
thimble (Picture Plate I-8) and placed in the sample
chamber (Picture Plate I-3). Typical extraction time
range from 4-6 hours. Because tomato is high in
moisture (>90%), one of the most critical steps in
the extraction process is the moisture reduction step
or drying. We examined the distribution of tissues
in marketable tomatoes obtained from the market for
the initial run and found that the outer, inner tissues
and tissues in the fruit cavities to be 57.7%. 19.12%
and 23.2% of the total fruit weight, respectively (Pic-
ture Plate I-10). This preliminary data suggested that
one of the major steps to eliminate moisture is to
eliminate liquid in the fruit cavity. Other factors af-
fecting extraction efficiency and recovery of lyco-
pene from tomato include temperature, CO2 flow rate,
pressures, and presence of other co-solvents. Ma-
nipulation of tomato such as drying (with or without
CO2) or freeze-drying to improve extraction effi-
ciency will be evaluated as it is known that some
drying will help in the handling and extraction. How-
ever, it must be assured that drying does not oxidize
the lycopene. We will continue to explore quality of
dried tomato products before CO2 critical fluid ex-
traction to see their potentials as novel functional food
ingredients. Because of a delay in funding, we will
evaluate the vine ripe cull tomatoes (from pin-hooker)
later this Fall.
Lycopene Determination in Tomato by HPLC:Because lycopene and other carotenoids in
tomato are unstable due to heat, light, air, and acid-
ity, these factors will be additionally evaluated. Ly-
copene stability and efficiency of the extraction pro-
cess will be monitored by HPLC methods described
by Simonne et al. (2001; 2002). Figures 1 and 2 show
some sample chromatograms of lycopene and other
carotenoids in tomato tissues (outer and inner tissues
and whole tomato). Carotenoid profiles for outer and
inner tissues as well as the whole tomato tissue are
similar, despite the difference in quantity. It appeared
that outer tissues contained higher lycopene than in-
ner tissues. Although lycopene is a major carotenoid
in tomato, lutein and beta-carotene are also present
in significant amounts in this tomato variety. This
finding will facilitate us in selecting tissues for the
CO2 extraction.
Objective 2To identify post-harvest handling procedures
which promote rapid carotenoid (primarily lycopene)
biosynthesis and other phenolic phytochemicals in
fresh-market cull tomatoes (Bala Rathinasabapathi,
Stephen T. Talcott, Steven A. Sargent, Jeff Brecht,
Abbie J. Fox, and Celia Sigua).
Materials & Methods
Post Harvest treatment of Cull Tomatoes:Tomatoes (‘FL 47’) were harvested on May
8, 2002, from a packinghouse in Palmetto. They were
run through the grading line and culled tomatoes were
collected directly from the cull conveyor. Three
samples were collected over a 30-minute period, with
two standard cartons representing one sample, and
these were brought to the Postharvest Horticulture
Laboratory in Gainesville.
The same day, the tomatoes were first classi-
fied into two groups, usable and unusable. Each group
was then classified by defect classification and color
stage. Subjective ratings were employed to rate to-
mato ripeness at harvest and during the storage pe-
riod according to U.S.D.A. grade standards for fresh
tomatoes. (See Tables 1, 2, 3).
Defect classifications were defined as follows (See
Picture Plate 2):
85
Usable: - slight cat-face and/or zipper, misshapen,
minor cuts, minor growth cracks and sound
(no defects).
Unusable - decay, severe cut (exposed internal tis-
sue), over-ripe (soft), undersize (immature),
insect damage and severe cat-face.
After sorting the greens from the ripenened
fruit, they were then sorted by defect category (cut,
growth crack, catface, and sound) and placed into
foam-cell trays. The green tomatoes were placed in
a flow-through chamber and exposed to 100 ppm hu-
midified ethylene; pink tomatoes were also placed
in a flow-through chamber but only exposed to hu-
midified air. The tomatoes were observed after 5 and
10 days storage at 68 EF for incidence of decay and
ripening rate (see Picture Plate 2).
Screening of lycopene levels bySpectrophotometry:
Culled tomatoes of cultivar FL-47 were
manually sorted into diseased, cut, catface, and
cracked, based on the defects found on the fruit. The
defects are illustrated in Picture Plate 2. Diseased
fruit were discarded. Some of the fruit that did not
have any of these defects were categorized as sound.
Stage 4 fruit, identified by the development of some
red color, in each defect category were incubated for
10 days at 20oC and stage 1 green fruits were treated
with 100 ppm ethylene at 20 EC for 10 days. At the
end of these treatments, color development was as-
sessed using a Minolta colorimeter.
Fruit in each category were sliced and separated into
“outer tissue” and “all other tissue” (all the interior
tissue), and pureed in a blender. A known volume of
water was added to puree the outer pericarp tissue.
Lycopene was extracted in a mixture of solvents (0.1
g puree, 2.5 mL acetone, 2.5 mL ethanol, and 5 mL
hexane) containing 0.05% (w/v) BHT (Perkins-
Veazie et al., 2001). Water (1.5 mL) was added to
separate the hexane fraction. Lycopene in hexane
was quantified using an UV-Visible spectrophotom-
eter (DU520, Beckman Instruments) at 444 nm, and
comparing to a standard curve made with pure lyco-
pene (Sigma Chemical Company, L9879). A scan of
the hexane fraction of the extracts closely resembled
that of the standard lycopene (Figure 3).
Each treatment (category of fruit, air or eth-
ylene) contained more than 10 fruit. Six fruit were
randomly chosen for lycopene extractions. For mea-
surements of weight, volume, and lycopene content,
two fruit were pooled together and triplicate values
were obtained. The data were analyzed using Analy-
sis of Variance (SAS statistical package). Duncan’s
multiple range test was applied for mean separation
at P=0.05.
Results and DiscussionResults of our study are presented in Table 5.
Our data indicate:
1. abThe fruit wall (pericarp), which contrib-
uted to 10 to 15% of the total fruit fresh
weight had significantly more lycopene per
g fresh weight than the rest of fruit tissue
(locular tissue).
2. abThe pericarp tissue of cracked tomatoes
receiving no ethylene treatment and sound
tomatoes receiving ethylene treatment had
the highest levels of lycopene (306 mg and
216 mg per g tissue). The locular tissue of
these fruit had about 1/3 less lycopene (89
and 86 mg per g tissue).
3. abSound fruit responded to ethylene treat-
ment by producing about 2-fold more
lycopene both in the pericarp and the
locular tissue (216 mg per g vs 105 mg per
g in the pericarp and 89 vs. 38 mg per g in
the locular tissue).
4. abMean lycopene levels in the pericarp of
fruit with cuts, catface, and cracks, and the
interior tissues of those with cuts, catface,
and cracks did not increase significantly or
increased only marginally in response to
ethylene treatment.
The conclusion was thatd many defects iden-
tified in culled tomatoes of cultivar FL-47 caused no
problems for lycopene development and extraction.
A standard ethylene treatment could improve color
development in certain categories of fruit but not oth-
ers. The results observed here will be verified using
culled fruit of the same variety harvested in a differ-
ent season.
Lycopene level per unit tissue weight is higher
in the outer pericarp compared to the interior tissues.
86
Hence, it will be useful to test whether separation of
the pericarp tissue from the rest of the tissues is of
any advantage for large scale isolation of lycopene
by supercritical CO2 extraction.
Non-Carotenoid PhytonutrientsTissue was blended in a Brinkman homog-
enizer to the smallest attainable particle size prior to
analysis. Polyphenolic analyses were conducted on
an aqueous extract following centrifugation using the
Folin-Ciocalteu for total gallic acid reducing equiva-
lents (Swain and Hillis, 1959) and also separated by
HPLC using the method of Talcott and Howard
(2000) against standards of p-hydroxybenzoic acid,
caffeic acid, and quercetin. Antioxidant capacity was
conducted using the ORAC assay of Ou (2002)
against a standard of Trolox, a synthetic, water-
soluble analog of vitamin E. Carotenoids were ex-
tracted from the original homogenate using hexane
containing 0.2% BHT as a preservative. Organic ex-
tracts were quantified by HPLC according to Howard
et al.(2000) and confirmed via spectrophotometric
readings at 444, 470, and 502 nm.
ResultsTreatments affecting biosynthetic rates of
phytochemicals are often quantified via non-
carotenoid phytochemicals, since these compounds
generally respond quickly to changing environ-
mental conditions. By measuring total reducing
compounds (total soluble phenolics) and those
compounds that are able to inhibit a specific
radical (peroxyl), an overall assessment of treat-
ment efficacy was obtained. No difference in
phytochemical concentrations or antioxidant
capacity was found due to ethylene exposure, and
no appreciable difference was found due to
preharvest selection of fruit (Table 6.). However,
outer tissue layers generally had higher levels of
total soluble phenolics (Folins) and flavonoid
glycosides that related to higher ORAC values.
Levels of hydroxybenzoic and hydroxycinnamic
acids were not different between tissues (Table 6.).
Antioxidant activity measured by the ORAC assay
factors on primarily polar antioxidants; therefore
contributions from lycopene were not correlated to
antioxidant capacity. However, more lycopene was
present in outer skin layers as opposed to inner
layers, which is apparent from visual observations.
Total phenolics and total flavonoid concentrations
were significantly correlated to ORAC values
(r=0.94 and 0.67, respectively) indicating their role
in antioxidant protection for the fruit, localized
where lycopene was most prevalent (outer tissue
layers). Lycopene concentrations were also corre-
lated to spectrophotometric readings at three
wavelengths (r>0.94) and along with good correla-
tions to antioxidant capacity these rapid assays
proved to be sufficient for phytochemical assess-
ment of tomatoes.
87
References
Howard, L R, Talcott, S T, Brenes, C H and
Villalon, B 2000. Changes in phytochemi-
cal and antioxidant activity of selected
pepper cultivars (Capsicum Species) as
influenced by maturity. J. Agric. Food
Chem. (48):1713-1720.
Ou, B, Hampsch-Woodill, M, Prior, RL 2001.
Development and validation of an im-
proved oxygen radical absorbance capacity
assay using fluorescein as the fluorescent
probe. J. Agric. Food Chem. (49):4619-
4626.
Perkin-Veazie, P, Collins JK, Pair SD, Roberts, W.
2001 Lycopene content differs among red-
fleshed watermelon cultivars. J Sci Food
Agric. (81):983-987.
Simonne, A, Simonne, E, and Eitenmiller, R. 2002.
Bitterness and chemical composition in
lettuce grown in the Southeast United
States. HortTechnol. (In press).
Simonne, A, Huang, T and Wei, CI. 2001. Cooking
time unequally affects carotenoids in
different vegetables. Paper presented at the
national IFT meeting in NewOrlean, June
23-27, 2001.
Swain, T, Hillis, WE 1959. The phenolic constitu-
ents of Prunus domestica. I. The quantita-
tive analysis of phenolic constituents. J.
Sci. Food Agric. (10): 63-68.
Talcott, S T, Howard, LR, Brenes, CH 2000.
Antioxidant changes and sensory properties
of carrot puree processed with and without
periderm tissue. J. Agric. Food Chem.
(48):1315-1321.
88
89
90
91
92
93
94
95
Figure 3. A Scan of tomato outer tissue extract (A) compared to lycopene standard (B).
96
Sanitation to eliminate hazardousmicroorganisms from tomato fruit
Jerry Bartz1, Keith Schneider2, Kelly Felky2,
and Steve Sargent3. 1Plant Pathology,2Food
Science and Human Nutrition, and 3Horticultural
Sciences Department, University of Florida, IFAS,
Gainesville.
AbstractWater sanitation procedures were examined
to determine how to kill Salmonella spp. that might
be deposited on tomatoes by field crews, various
wild or domestic animals or through wind-blown
rainfall. Dried deposits were successfully inacti-
vated by a 2 min treatment with 150 ppm free
chlorine at pH 6.5 and 35 or 45oC. A portion of the
deposits were washed from the fruit by the action
of the scale model flume and were found to con-
taminate nearby clean fruit. The presence of the
chlorine in the water prevented this dispersal.
However, bacteria deposited in shaved wounds, the
stem scar or surface punctures were not inactivated
by the chlorine. Chlorine alternatives were tested
for cleaning fruit. Acidified sodium chlorite,
hydrogen peroxide, chlorine dioxide and peroxy-
acetic acid equaled or exceeded chlorine in effi-
cacy. However, price, odor control, efficacy
against decay pathogens, and worker safety issues
have not been fully explored.
Proposal and objectivesTwo potential microbial hazards have been
associated with fresh market tomatoes sold in the
U.S.A. Direct losses due to postharvest decays
have been associated with the inoculation of
tomatoes by plant pathogens during postharvest
handling (Bartz, 1980, Ceponis et al., 1986),
whereas indirect losses have been associated with
the contamination of tomatoes by certain human
pathogens. Primarily due to weather conditions,
occasional outbreaks of postharvest decays accom-
pany field production of tomatoes. While
postharvest decay losses are uncommon, they are
not unusual, particularly during rainy periods. A
theoretical, but greater risk involves the contami-
nation of fruit by enteric pathogens of humans.
Although bacteria responsible for food-borne
illnesses have never been directly isolated from
Florida-grown tomatoes, a trace back analysis in
2000 implicated Florida tomatoes in a outbreak of
salmonellosis associated with a fast-food chain.
Given the number of boxes of tomatoes
shipped out of Florida over the years and the
absence food-borne illness outbreaks actually
traced to those tomatoes, one could conclude the
risk of contamination is non-existent. However, as
noted above, Florida tomatoes were suspected of
being involved in one outbreak. Effective hazard
control dictates that food industries do everything
possible to produce a wholesome product and this
fact must be communicated to consumers (Powell,
2001).
Our objectives in this proposal were to
determine the chlorine concentration, solution pH
and water temperature needed to:
(i) disinfect organic deposits as they
are washed from fruit surfaces;
(ii) prevent the accumulation of human
pathogens in dump tanks and
flumes;
(iii) prevent dispersal of human patho-
gens among tomatoes in a flume;
(iv) disinfect areas on fruit that were in
contact with contaminants;
(v) control microorganisms on surfaces
that contact fruit during harvest and
handling such as picking containers,
field bins, and packing lines.
The soft rot bacterium, Erwinia carotovora,
will be used as a surrogate for human pathogens to
determine effective chlorine treatments for pre-
venting contamination and eliminating contami-
nants. The effectiveness of the final treatments
will be validated in tests with a five-strain cocktail
of Salmonella spp.
AchievementsA graduate student whose assistantship was
covered through a tri-state food safety grant en-
abled us to immediately conduct experiments with
the five-strain cocktail of Salmonella spp
Five serovars of Salmonella, S. agona, S.
gaminara, S. michigan, S. montevideo, and S.
Poona, were kindly provided by Dr. Linda J.
Harris, U. Ca., Davis. Rifampicin resistance was
97
induced in the strains to allow easier recovery of
Salmonella from treated fruit. Maintenance of the
cultures and production of inoculum followed
standard microbiological procedures. For produc-
tion of inocula, cultures were grown in liquid
culture, removed by centrifugation and washed
twice with phosphate buffer saline (PBS) (Sigma-
Aldrich, St. Louis, MO) to eliminate substances
that would react with the test sanitizers. All five
strains were combined as a cocktail and diluted in
phosphate buffered saline (PBS).
Ten 10 _L- samples of the bacterial suspen-
sion were spotted at separate locations on blemish
free portions of the fruit surface for a total of 1.0 x
108 CFU/tomato. The spots were allowed to dry
for 1 h before treatment. In subsequent tests,
various types of wounds and the stem scar were
inoculated with the Salmonella cocktail. The dried
bacterial deposits simulated organic debris in
objective no. 1.
Chlorine stock solutions were prepared
from a sodium hypochlorite concentrate, diluted to
50, 100, or 150 ppm with phosphate buffer and
adjusted to pH 6.5, 7.5, and 8.5. The free chlorine
concentration was verified using methods ap-
proved by the U.S. Environmental Protection
Agency.
Whole pink or green tomatoes inoculated
and dried as above were placed in a circulating
water bath. Water temperatures were adjusted to
25, 35, or 45°C depending on the test. The circu-
lating water bath simulated a flume as found in
tomato packinghouses. Tomatoes were removed at
15, 30, 60 or 120 seconds after being placed in the
bath. The bacteria on the tomatoes were recovered
by standard methods. The water in the bath was
tested for viable bacteria as well.
After determining the most effective pH
with 50 ppm free chlorine, we examined the
efficacy of 100 and 150-ppm chlorine at solution
temperatures of 25, 35, or 45oC (77, 95 or 113oF,
respectively). Tomatoes with various wounds
(puncture, shaved area or stem scar) were inocu-
lated as above and treated with 150-ppm chlorine
at pH 6.5 and 45oC as described in tests on surface
populations.
Aqueous solutions of alternative sanitizers
were prepared at maximum allowable concentra-
tions and used to treat inoculated tomatoes for up
to 2 min. Surviving populations of Salmonella
were then recovered from the treated tomatoes as
described for tests with chlorinated water.
Based on the literature and popular recom-
mendations, 50 ppm free chlorine is more than 50
times more concentrated than the amount required
to kill suspended cells of Salmonella within 2 min.
However, when cells are allowed to dry on depos-
its on tomato fruit, they are clearly more difficult
to kill. A few bacteria on the fruit survived expo-
sure to 50 ppm free chlorine for 2 min (Fig. 1)
98
Salmonella were not detected in the flume water,
evidence that bacteria washed from the fruit were
killed immediately. This precluded an accumula-
tion in the water. The 50-ppm solution was
slightly more effective at pH 6.5 than at 7.5 or 8.5.
This is consistent with the literature on the species
of chlorine in solution and the solution pH (White,
1999). Hypochlorous acid predominates over
hypochlorite ion at pH levels less than 7.5. Hy-
pochlorous acid is between 20 and 300 times more
effective in killing various bacteria than is hy-
pochlorite ion.
When fruit are dumped into a simulated
water flume containing plain water, populations of
Salmonella on the fruit decrease by 1 to 2 logs
within 2 min (Water Rinse line, Fig. 2.)
This represents suspension in the water of about 9
X 105 cfu per fruit. Although 90 to 99 % of the
bacteria were removed from the fruit surface just
by action of the moving water, a substantial num-
ber remained. When clean fruit were placed
together with the contaminated fruit, the clean fruit
picked up nearly 103 Salmonella per fruit, evidence
that cross contamination will occur if the flume
does not contain an effective sanitizer such as
chlorine. The bacteria suspended in the water also
will likely contaminate equipment down stream
from the flume and ultimately, the entire
packingline will be a source for contamination of
the tomatoes that are being packed. The Salmo-
nella cocktail was killed more rapidly at 150 as
compared with 100 or 50 ppm, particularly with
shorter exposure intervals. Complete elimination
of Salmonella from the fruit surface occurred only
with the 150-ppm concentration, but required the
full 2-min exposure.
The chlorine solutions warmed to 35 or 45 C were
more effective than the 25-C solution although
there was no statistical difference in efficacy
between the 35 or 45 C solutions.
99
When wounds (punctured, shaved or stem
scar) were inoculated with the Salmonella cocktail,
treatment with 150 ppm chlorine at pH 6.5 and
45oC had little effect on populations in the wound.
This is consistent with the literature. Wei et al.
(1995) and Zhuang et al. (1995) both reported that
Salmonella suspensions placed on the stem scar
region of tomatoes were not inactivated (decreased
by up to 99 but not 100%) by subsequent exposure
to 100 or up to 320 ppm chlorine, respectively for
2 min.
Although chlorinated water does not disin-
fect various wounds on tomatoes that have been
contaminated with Salmonella or other hazardous
microorganisms, which includes decay pathogens,
it can inactivate deposits on the skin and prevent
accumulations in the water of dump tanks, flumes
or washers. By inactivating skin deposits and
preventing water accumulations, proper water
chlorination minimizes microbial hazards in fresh
market tomatoes. Proper water chlorination is
defined as maintaining at least 150 to 200 ppm free
chlorine in water at a pH of 6.0 to 7.5 and a tem-
perature of 35 to 45oC. The tomatoes should have
a residence time of at least 1 min. The free chlo-
rine concentration should be measured frequently
since the chemical reacts rapidly with tomato
surfaces as well as various materials accompanying
the fruits when they are dumped into the packing-
house water system. Alternatively, an oxidation-
reduction potential (ORP) system can be installed,
which automatically maintains a set ORP. The set
ORP should be determined prior to the addition of
tomatoes when the system has been filled, warmed
and chlorinated to the desired range.
Discussions were made with several manu-
facturers of instruments to measure water sanita-
tion. The sensors employed are designed for use in
clean water systems or systems with suspended
particulate matter, such as swimming pools, sew-
age treatment plants, etc. They become quickly
fouled out when used in water containing irregular
suspended solids, such as dump tank water. The
response time of these sensors is somewhat slow,
more than 1 minute. In-line colorimetric analyzers
are also designed for clean water systems and these
are limited to measuring free chlorine below 5
ppm. Therefore, for now, the best option appears to
be correlating ORP with free chlorine.
There are currently no calibration systems
available for pH/ORP control systems. There is
potential to develop a stand-alone, automated
calibration system that could be added to an exist-
ing pH/ORP system. The key to a reliable calibra-
tion system would be to have a standard solution
that would remain stable over time for periodic use
during calibration. To find if dilute chlorine
solutions were stable, we prepared a standard
solution in the laboratory according to UF/IFAS
recommendations. About 100 ppm free chlorine
was added to 1 liter of deionized water and then
adjusted to pH 7.0. This solution was held at about
74 oF, shielded from light and sealed with a stop-
100
per. Over a period of 14 days the solution pH
and concentration of free chlorine remained
stable as measured by a digital pH meter, digital
ORP meter and Hach colorimetric free-chlorine
test. One company, Analytical Technologies,
Inc., a manufacturer of sensors, has indicated
interest in working with Florida packer/shippers
in designing a prototype automated calibration
unit. This will be explored in the upcoming year.
The “proper water chlorination” de-
scribed above will also prevent the accumulation
of bacterial and fungal decay pathogens and will
prevent fruit from becoming inoculated in the
flume (Bartz et al., 2001). Both the pH range
and the solution temperature are critical compo-
nents of proper water chlorination. Higher pH
solutions do not have more stability in the tank
than to those in the 6.0 to 7.5 range, but are
slower acting (Bartz, unpublished).
Acidified sodium chlorite (1200 ppm),
hydrogen peroxide (5%), and peroxyacetic acid
(80 ppm) were more effective in removing
Salmonella from fruit surfaces than was 150
ppm chlorine at pH 6.5. These chemicals will
next be tested for efficacy against fungal decay
pathogens. Also, relative price and odor issues
will be explored. Chlorine dioxide (5 ppm) was
about equal to chlorine in efficacy. However,
use of this chemical at 5 ppm in an open dump
tank, flume, and then washer water system is
known to have odor and safety issues. Ozone at
1.3 ppm was not as effective as chlorine, was
difficult to create due to instability and like
chlorine dioxide would have odor and safety
issues. Two other alternatives for water sanita-
tion, UV light and copper ion, were not tested.
UV light would not produce a germicidal at the
initial fruit contact with water. Copper ion,
while effective in clean swimming pools, would
not kill bacteria within seconds of contact.
Bartz, et al. (2001) and Johnson (1945) noted
that bacteria and water soluble dyes moved into
wounds and water congested natural openings in
plant tissues instantaneously apparently through
capillary forces. These observations explain
why 150 ppm chlorine does not disinfect con-
taminated wounds (the bacteria become deeply
embedded in the wound) and also why Salmo-
nella on tomatoes have to be killed within seconds
of contact with the water.
Literature Cited
Bartz, J. A. 1980. Causes of postharvest losses in
Florida tomato shipments. Plant Dis. 64:934-
937.
Bartz, J. A., Eayre, C. G., Mahovic, M. J.,
Concelmo, D. E., Brecht, J. K., and Sargent,
S. A. 2001. Chlorine concentration and the
inoculation of tomato fruit in packinghouse
dump tanks. Plant Dis. 85:885-889.
Bartz, J. A., Mahovic, M, and Concelmo, D. 2001.
Rapid movement of inoculum into wounds
on tomato fruit. (abstr). Phytopathology
91:S6.
Ceponis, M. J., Cappellini, R. A., and Lightner, G.
W. 1986. Disorders in tomato shipments to
the New York market, 1972-1984. Plant Dis.
70:261-265.
Dychdala, G. R. 1991. Chlorine and chlorine
compounds. p. 131-150. In: S. S. Block
(ed.). Disinfection, sterilization, and preser-
vation. Lea & Febriger, Philadelphia.
Johnson, J. Infection experiments with detached
water-congested leaves. Phytopathology
35:1017-1028.
Powell, D. A., 2001. Food safety and the consumer
– Perils of poor risk communication. Can. J.
An. Sci. 80(3 ): 393-404.
Sherman, M., Showalter, R. K., Bartz, J. A., and
Simone, G. W. 1981. Tomato packinghouse
dump tank sanitation. Veg. Crops Fact Sheet
VC-31, Fla. Coop. Ext. Serv. Univ. Fla. Inst.
Food Agric. Sci. Gainesville, 4 p.
Wei, C. I., Huang, T. S., Kim, J. M., Lin, W. F.,
Tamplin, M. L., and Bartz, J. A. 1995.
Growth and survival of Salmonella
montevideo on tomatoes and disinfection
with chlorinated water. J. Food Prot.
58:829-836.
White, G. C. 1999. Handbook of Chlorination and
Alternative Disinfectants. 4th. ed. Van
Nostrand Reinhold, New York.
Zhuang, R.-Y., Beuchat, L. R., and Angulo, F. J.
1995. Fate of Salmonella montevideo on
and in raw tomatoes as affected by tempera-
ture and treatment with chlorine. Appl.
Environ. Micro. 61:2127-2131
101
Competition in the Winter FreshTomato Market
John J. VanSickle, Director
International Agricultural Trade and Policy Center
Food & Resource Economics Department, IFAS
University of Florida
Gainesville, FL 32611-0240
AbstractCompetition in the U.S. winter fresh tomato
industry continues to be intense and it is critical for
Florida growers to monitor the situation within this
market. Analyses of costs of producing fresh
tomatoes in Mexico indicates that costs have
increased significantly over the last 7 years and
that the advantage once derived from the devalua-
tion of the peso has disappeared. While costs of
producing and exporting tomatoes to the U.S.
market fell from $7.52 per 25 pound carton equiva-
lent in the 1990/91 season to $5.31 per carton in
the 1994/95 season, inflation has since caused
those costs to increase to $7.35 per carton in the
2000/01 season. The Florida industry also has been
aggressive in their education and promotion pro-
grams to increase the demand for Florida fresh
tomatoes. An evaluation of those expenditures
indicates that growers have realized a return of
6.25 percent on that investment, with added profits
of $20.67 million in their operations.
IntroductionThe winter fresh tomato industry has
witnessed several changes over the last several
years, beginning with increased competition from
Mexico, the entrance of greenhouse grown toma-
toes and the resulting trade disputes that followed
this increase in competition. Competition must be
monitored and the Florida industry must manage
their resources to give them the best opportunity to
compete in this marketplace.
As part of this project several products
have been developed to help the Florida tomato
industry. An evaluation of the education and
promotion program was completed in December,
2001, as part of the requirement to conduct these
activities as part of the Federal Marketing Order
(VanSickle and Evans, 2001). The results of that
analysis indicated that growers were benefiting
from the education and promotion programs being
funded by the marketing order. The average return
to investment in education and promotion activities
was estimated to be 6.25% with Florida growers
adding $20.67 million in profits to their operations
from these activities.
This project also contributed to the infor-
mation that was required for the trade dispute filed
against Canadian greenhouse tomato growers. One
of the key issues in that case involved determining
the ‘like product’ for calculating injury. A test was
proposed for this issue that was not accepted by the
International Trade Commission, but a publication
is being prepared for review within the scientific
community that may help in defining the means for
testing for ‘like product’ (Evans et al., 2002).
This project also contributes to the knowl-
edge necessary for assessing competition with
Mexico by providing updates on the costs of
producing tomatoes in Sinaloa, Mexico, and
exporting those tomatoes to the U.S. market. The
results of that analysis indicates that costs in
Mexico have increased relative to Florida as
inflation has increased more than in the U.S. since
1994/95. Costs in Mexico were lowest in the 1994/
95 season with a delivered in cost of $5.31 per
carton. Costs have increased since then to $7.35
per carton in the 2000/01 season. A discussion on
this analysis follows.
Methodology used to estimate costsin Mexico
The budgets developed for Mexican grown
tomatoes are based off of estimations by VanSickle
et al. (1994) made for the 1990/91 crop year and
on budgets published by the Confederacion de
Asociaciones Agricolas Del Estado de Sinaloa
(CAADES). CAADES is the umbrella organization
for grower organizations organized in the state of
Sinaloa, Mexico. The VanSickle et el.report was
completed as an assessment of competition in the
U.S. market for fresh winter vegetables. The
CAADES reports are published annually from
information supplied by growers to CAADES.
The baseline numbers for 1990/91 are taken
directly from VanSickle et al. and converted into
total costs in pesos per hectare of production. The
102
preharvest costs reported by VanSickle et al. were
reported in dollars per acre. Those numbers were
converted to pesos per hectare by multiplying the
numbers by 2.471 to get the hectare equivalent and
then multiplying by 2950 to get the peso equivalent
cost. The harvest and post harvest expenses re-
ported by VanSickle et al were on a per unit cost
basis. Those costs were converted to a per acre
equivalent by first multiplying the per unit cost by
the exchange rate of 2.95 to get the peso equivalent
cost. The harvest and haul and packing costs were
then multiplied by the total per hectare yield of
2,718 cartons to get the total cost in pesos for
harvest and haul and packing charges on a per
hectare basis for 1990/91. The per unit marketing
charges for transport to the border, tariff, other
crossing fees and selling cost were multiplied by
the exchange rate in 1990-91 of 2.95 and then by
the export market yield of 2174 to get the per
hectare peso cost of these items.
1994/95:The 1990/91 preharvest cost items of land
rent, labor, machinery and misc/overhead were
adjusted by the change in the producer price index
of intermediate materials for preparation of fruits
and legumes (Banco de Mexico, 2002) from
September, 1990, to September, 1994, (1.42) for
the 1994-95 season. The 1990/91 preharvest cost
items of transplants, fertilizers and pesticides were
adjusted according to the changes recorded in the
CAADES budgets from 1990/91 to 1994/95.
Changes in these costs capture much of the tech-
nological change in tomato production relative to
other items.
The interest rate expense was calculated by
summing all other preharvest costs and then apply-
ing the interest rate reported as the money market
representative interest rate (Banco de Mexico,
2002) of 24.73% for 55 days, the same method as
applied by VanSickle et al..
The 1990/91 harvest and post harvest
expenses of harvest and haul and packing were
adjusted by multiplying the 1990/91 per unit costs
reported in dollars/carton by the January 1991
exchange rate of 2.95 and then by the change in the
producer price index of intermediate materials for
preparation of fruits and legumes from January,
1991 to January, 1995(1.50) to account for infla-
tion. That product was then multiplied by the total
yield for 1994/95 of 3843 to get the cost in pesos
per hectare. The total yield was derived from the
CAADES reported export yield of 3074 which was
divided by .8 to get the total yield.
The 1990/91 marketing expenses for
transport to the border and other crossing fees were
adjusted by multiplying the total cost calculated for
1990/91 by the change in the producer price index
of intermediate materials for preparation of fruits
and legumes for Mexico from January, 1991, to
January, 1995 (1.50).
The tariff cost was calculated by using the
per unit weighted average tariff rate reported by
VanSickle et al. (0.46) discounted 20% to account
for lower tariffs resulting from NAFTA and multi-
plying it by the January, 1995 exchange rate of
5.6405. That product was then multiplied by the
export yield of 3074 to derive the per hectare cost
of the tariff.
Selling costs for 1994/95 were calculated
by using the baseline total costs calculated for
1990/91 and adjusting those for the increase in
export yield (3074 reported in 1994/95 compared
to 2174 reported in 1990/91) and for the change in
unit value as reported by the U.S. Department of
Commerce (DOC) import statistics ($706.73 per
metric ton in 1990-91 compared to $684.72 in
1994/95). The average unit values were calculated
using monthly imports and average values for the
January to May periods in 1991 and 1995 as
reported by DOC.
1995/96 and following seasons:Adjustments for 1995/96 and following
seasons were made following the same procedures
as used for 1994/95. The inflation factor was
highest in the 1995/96 season following the large
devaluation in the peso from 1994 through 1996.
The pre-harvest costs inflation factor was 1.49 in
the 1995/96 season and the post-harvest costs
inflation factor was 1.52. The last reported yield
increase occurred in the 1995/96 season with a
reported export yield was 4500 and the total yield
was 5625. The interest rate used in interest cost
calculations peaked in 1995/96 at 42.35%, but
declined to 16.5% in the 2000/01 season. The tariff
103
rate was discounted an additional 10% for each
season to account for NAFTA reductions with the
tariff scheduled for elimination in January 2003.
ResultsThe results of these analyses indicate that
total costs for exporting tomatoes to the U.S. from
Mexico reached their lowest level in 1994/95
following the large devaluation in the peso that
occurred over that period. Since then inflation has
occurred to offset that cost reduction and per unit
costs are only slightly lower than the cost reported
in 1990/91. Clearly the advantage that was af-
forded Mexico from the devaluation of the peso
has been offset by inflation and technology devel-
opment relative to technology in Florida will be the
deciding factor on competitiveness between these
two areas.
References
Banco de Mexico. 2002. www.banxico.org.mx
Evans, Edward, Jione Jung, John J.VanSickle, and
Robert Emerson. 2002. “A Test to Deter-
mine Like Products: The Case of Green-
house Tomatoes.” Working paper.
VanSickle, John J., Emil Belibasis, Dan Cantliffe,
Gary Thompson and Norm Oebker. 1994.
“Competition in the U.S. Winter Fresh
Vegetable Industry.” USDA ERS AER 691.
VanSickle, John J. and Edward Evans. 2001. “The
Florida Tomato Committee’s Education and
Promotion Program: An Evaluation.” Paper
submitted to USDA AMS by the Florida
Tomato Committee.
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105