table of contents - ohio state university

TABLE OF CONTENTS

Summary of Results from the Study of COp Enrichment of GreenhouseAtmospheres for Tomatoes, by Dale W. Kretchman and Freeman SHewlett, Department of Horticulture **..«* ............ ..

Effect of Nitrogen and Potassium Soil Applications and Leaf Contenton Yield and Occurrence of Fruit Defects, by Freeman S. Hewlettand Dale W. Kretchman, Department of Horticulture.*. ...... . «... 7-9

Predicting Harvest Maturity of Greenhouse Tomatoes^ by William M.Brooks, Department of Horticulture ......... .......... ....... ».* 11- lU

Breeding Tomatoes for Mosaic Resistance, by Leonard J. Alexander,Department of Botany and Plant Pathology.*.*.. .............. **• 15-17

Studies on the Inheritance of Tobacco Mosaic Virus Resistance inTomato, by Matteo P. Cirulli and Leonard J* Alexander,Department of Botany and Plant Pathology ..... . ............. * . * * 18-22

Soil Sterilization in Relation to Control of Greenhouse VegetableDiseases, by Robert E. Partyka, Department of Botany andPlant Pathology ............. . .................................. 23-25

Retail Margins, by M* E* Cravens, Department of AgriculturalEconomics and Rural Sociology. .......... .......... ......... .... 27-28

Tomato Quality Studies, by M* E. Cravens, Department of AgriculturalEconomics and Rural Sociology. . .... .......................... . * 29-31

Consumer Preferences for Greenhouse Tomatoes, by P. R. Thomasand E. J* Royer, Department of Agricultural Economics andRural Sociology ... ............ ...... .............. ..... ........ 33-36

U/65-800

5/65-1000

SUMMARY OF RESULTS FRCM THE STUDY OF COg ENRICHMENT OF GREENHOUSE ATMOSPHERESFOR TOMATOES

Dale Wo Kretchman and Freeman S« HewlettDepartment of Horticulture

Ohio Agricultural Experiment Station

Investigations of thec interaction between carbon dioxide (002) enrich-ment, day air temperature, and light intensity as affecting growth, yield, andquality of greenhouse tomatoes have been in progress for one growing season*Data from a spring crop and a fall crop have been compiled and analyzed*

Tables 1-U give a general idea of C02 levels, temperatures, varieties,and types of data recorded*,

The time of adding COg is of particular importanceo During the springcrop, the gas was added daily from Feb« 6, 196U (10 days after transplanting)until late March and then intermittently until mid-April because of excessiveventilation on warm, sunny days. The gas was added from Oct* 8, approximatelythe same date of first harvest, to Dec* 26 during the fall crop«

Results of the effects of added COg on fruit size, yield, and grade asreflected by U.S. No» 1 standards are presented in Table 1* These data aremean values of the two day temperatures used and the several lines and hybridsgrown in each crop. The added COg treatment in the spring crop resulted in areduction ef smaller sized fruit (2ol±-k oz.) and a significant increase in theyield of fruits larger than 6*2 oz* The pack-out of tLS* No, 1 fruit alsoreflected this general size increase from added levels of COgo The overallincrease from increased levels of COg was 1*9% of total yield and 2»ltf> of ILS*Na. 1 fruit.

Additional amounts ©f COg did not significantly increase fruit size inthe fall crap, except for an increase in weight of fruit over 9*8 oz0 Therewas a general increase of 601$ in total yield and 2o2% in U.S« N0o 1 fruitfrom the added COg treatment* This lower response for the fall crop was natsurprising since gas was added late in the season and hence had less effectan plant growth than when it was added early in the spring crap* Data anplant growth rate and final plant weight for bath crops indicated this ta betrue*

The lines and hybrids varied considerably in respanse ta added COg andwere nat consistent for the tw® craps (Table 2)* The greatest increases intatal yield far the spring crap accurred in R 2U and R 25, with 13«li and 12 .Q#increases respectively0 Hybrid 0 increased 9*1$ and WR 7 decreased Io6j6oHawaver, during the fall crap, MR 1 increased 7<»1#, R 25 2*1# and hybrid 010oi$o Thus, frem these limited data, Hybrid 0 is apparently mare cansistentin its respanse ta COg than the ether lines ar hybrids used in this study* The

variation in varietal or selection response could be one explanation for thewide differences in yields from supplemental C02 which is found in the litera-ture and grower experiences*

Growing temperaturf is another factor that undoubtedly has been asso-ciated with variation in response of tomatoes to CCU. Results presented inTable 3 do not confirm the premise suggested in the literature that growingtemperatures should be higher than normal when CO 2 is added to the atmosphere*There was no increase in total yield at the 73° - 81° F. range with supplemen-tal C02 as compared with the more favorable range of 6£° - 77° F* during thespring crop. There was, however, an increase in total yield from added CC>2 of*76 lbs» per plant at 69° - 77° F. as compared to the more favorable 65° - 73°F* temperature for the fall crop* But, there was only a ,2 Ib* per plantincrease over the normal level of C02 at the higher temperature* Thus, it appethere is no justification for increasing day temperatures when using supplementCC>2 for growing greenhouse tomatoes, especially considering the increase infruit quality defects encountered at higher growing temperatures 1 A

The influence of supplemental CC^ on fruit quality defects is summarizedin Table U* Of the nine defects upon which data were taken, the effect ofC02 on fruit cracking was most apparent. Added GC caused a statisticallysignificant increase in cracks for both the spring and fall crops. Thiscould be the cause in part for the reduced amounts of U»So No, 1 fruit in com-parison to total yield (Table 1)* This is a very disturbing response requir-ing more study to determine the cause and a possible method for its eliminatior

The added COg treatment did not result in an earlier first harvest duringthe spring crop* However, fruit were picked 3 to 7 days earlier from the high*temperature plots than the lower temperature plots, regardless of CC>2 treat-ment* CC>2 obviously had no effect on first harvest of the fall crop becausethe added CC>2 treatment was not started until harvest had begun*,

Leaf analysis data are being taken on the nutritional status of tomatoplants grown under higher than normal atmospheres of COp. Preliminary indi-cations are that plants grown in an enriched atmosphere may have leaf con-tents lower in nitrogen and iron and thus may require higher levels or morefrequent applications of these nutrients« The nutritional aspect of thisinvestigation needs additional study before general recommendations can be mad<

It is obvious from the data obtained thus far that much more work needsto be accomplished to determine accurately the response of greenhouse tomatoesto added levels of C02*

Howlett, Freeman S., W0 No Brown and K*Jo Hood. 196U* Day air temperaturin relation to yield and fruit quality attributes of six varieties, linesand hybrids of the greenhouse tomato.Proc., Ohio Veg* and Potato Growers Assoc. h9* £0-61j,o

Table 1» - Influence of C0? on yield and pacloout,

Lbs. Fruit Per Plant

Total ILS. No. 1

+ 002 ~C02 * C02

Spring Crop;

-2.7 02.2.8-U4U.5-6.26.3v9.7

9.8 +Total

Fall Crop

-2.72.8-1+4U. 5-6. 26.3-9.7

9.8 +Total

•5U2.303.793.35.80

10.78

.321472.77245.78

7.79

482.00*3.60U.17**1.3&K*

11.63

.331.6U2.91247.95*

8.30

*•

1.382.331.69.17

5.57

..77

1.631.09.08

3.57

ax

1.08**2.172o05##,32-^

5.62

.

.881.611.06.11

3.66

Symbol "+" denotes added COg treatment (500-200C jpm)and "-", no added C02 '"•"* f" — v

* and ## indicate significant differences between C02 treat-ment means with any one size at the 95$ and 99% levels ofprobability*

Table 2. - Influence of C02 on yield of several lines and hybrids, 196U-

Total Ibs. fruit per plant

WR-BSyb.I$rb.R-R-R-

701

2U2529

Spring-C02

11.0811.2311.0910.6110.83

9*80

+ oo2

10.9012.29n.3312. OU12.1311.11

Fall-C02

7.367.95.

-8.08

+ C02

7.958.78--

8.25

Table 3* - Relation of day air temperature and C02 to yield, 196U*

Lbs* of fruit per plant

Spring

Fall

69-77 °F 1 /73-81

65-7369-77

11.1010.75

7.118.1t8

11.7011.60

7.928.68

1 / Day temperature ranges, low temperatures within each rangeused during low ligjht intensity, and higher temperatures athigh light intensity* Night temperatures were 62° F» forspring crop and 60° F* for fall crop.

Table 1*.- Influence of C02 on fruit quality defects, 1961*.

Percent Fruit Showing Defect in Each Size

Defect C02 -2.7 2.8-1*.!* l*.5-6.2 6.3-9.7 9.8 + (oz.)

Spring Crop

Puffiness +

Cracks +

Burst +

Scars +

Color +

Off -Shape +

Fall Crop

Puffiness +

Cracks +

Rough +

Scars +

Off -Shape +

55.150.9

56.853.0

9.87.9

.33*

.98

23.926.9

3.05.1

82.281*. 8

13.9*5.1

-

3.83.5

-

16.315.9

1*2. 1#*31*. 9

9.8*7.5

1.21.3

25-5*21.9

5.95.3

33.035.9

23.8*17.9

-

3.83.1

3.82.9

10.113-0

1*1.3**35.5

9.2*7.1

1.61.2

2l*.l23.5

8.8*10.3

21.822.1

37.3**28.8

-

U.2U-3

8.17.8

9.1**13.U

53.2*W.3

10.3*7.1*

U.l*3.1

28.927.9

20.723.3

23.321.8

52.U*liU.3

_

18.117.1*

31*. 332.3

12.516.7

71*. 270.7

13.111.6

33.937.8

38.539.2

56.1**67.5

31.631.7

63.151.9

10.213.1*

75.676.1*

81*. 186.8

# and *# denote significant differences between C02 treatment means withinany one size of individual defect at 9$% and 99% levels*

Greenhouse Vegetable Research,, Research Summary 1Ohio Agricultural Experiment Station, coster, Ohio* April 1965*

This page intentionally blank.

EFFECT OF NITROGEN AND POTASSIUM SOIL APPLICATIONS AND IEAF CONTENT ONYIELD AND OCCURRENCE OF FRUIT DEFECTS

Freeman S. Hewlett and Dale Wo KretchmanDepartment of Horticulture


The relation of soil and leaf nitrogen and potassium to yield and occurr-ence of certain fruit defects is a major objective of research initiated withthe spring 196U greenhouse tomato crop. Available experimental evidence indi-cates that increased nitrogen applied to the soil may result in reduced fruitsetting and, consequently, reduced yieldso

The objective of the work reported here is to ascertain the effect ofincreasing levels of nitrogen and potassium applied to a soil already high inthese nutrient elements upon total yield and the occurrence of certain fruitquality defects* In addition, the relation of leaf nitrogen and potassiumto yield and quality defects is receiving major attention*

Thirty-six plots, each 8 by 10 feet received applications of nitro-gen ranging from 0 to 280 Ibs. per acre, and potassium from 0 to 635 Ibs* peracre. Ammonium nitrate and potassium sulfate were the fertilizer salts used*Five equal applications were made March 2 and 15, April 1 and 15, and May 1*

At the beginning of the experiment, soil pH ranged from 6*6 to ?•£>phosphorus from 132 to 500 Ibs* per acre and potassium from 2i*6 to 1290 Ibs*^per acre* At the end of the spring crop, soil pH ranged from 606 to 7»3>phosphorus from 205 to ij.00 Ibs* per acre and potassium from 150 to 1080 Ibs*per acre0

The crop was planted Jan* 23, 196 o A 10-52-17 solution was appliedaround the plants at time of planting and a 20-20-20 starter solution wasapplied on Feb* 5» Night air temperature was set at 60° F0 with day tempera-tures 67-75° F», depending upon prevailing light intensity<> Peanut hullswere used as mulch.

gffect of soil application of nitrogen and potassium upon yield and quality;i

Total Yield - No significant effect upon total yield was obtained inthis fruit crop* There was some indication that increased nitro-gen increased the number of very small fruits at an potassiumlevels.

Total and Specific Defects - The data indicated no particular relation-ship between total or specific defects resulting from the nitrogenand potassium applications.

Relation of yield and quality defects to nutrient element content of the leave.'

Total Yield - At the final leaf sampling date, total weight of fruit wasnegatively correlated with total nitrogen* This was true in leavesfrom both the sixth and eighth fruit clusters.

Total Defects - At the second, third, fourth and fifth sampling dates*total defects increased as leaf nitrogen increased.

Specific Defects - Puffiness, cracking, off -color, and off-shape werethe principal defects observed.Puffiness - Puffiness increased as nitrogen increased in the

foliage .Cracking - Cracking increased as nitrogen increased but to a

lesser extent than puffiness*Off -Color - Off -color increased as leaf manganese increased.

This was a striking and unexpected positive correlationOff -Shape - Off -shape fmits tended to increase as leaf potassium

increased.

Time of occurrence of puffy and off- color fruits;

Puffy - Puffiness began early in the picking season and reached a peakJune 1. During June, the percentage showed a continuous decrease

Off -Color - Off color fruits continued to increase from March 31 untilthe end of the season*

Correlations between nutrient elements in the leaves:

As the plants aged* the number of significant correlations increased within the leaves removed at successive sampling dates.

The major positive correlations (1$ level of significance) were:

Nitrogen and PhosphorusNitrogen and PotassiumPhosphorus and PotassiumSodium and ManganeseCalcium and Boron

The major negative correlations were:

Potassium and MagnesiumPotassium and Sodium

Preliminary results from the fall crop, 196U:

Total Yield - No particularly significant effects of soil additions ofnitrogen and potassium upon yield were obtained.

Total Defects - Although the data have not been thoroughly analyzedlittle significance was evident between soil nitrogen and potas-sium additions upon total quality defects.

8

Specific defects:

Puffiness - Puffiness was much more prevalent in the smallest (to 2.702.) and largest fruits (over 9»8 cz.)» This disorderincreased after 1*0 days of harvest or approximately Nov. 10.

Cracking - Cracking was much more prevalent in large fruits and decreasedas fruit-size decreased. Cracking also showed a progressivedecrease as the season advanced.

Leaf analysis has not been completed so correlations of leaf nutrientelement content and yield and quality defects are not yet available.

Greenhouse Vegetable Research, Research Summary 1Ohio Agricultural Experiment Station, Wooster, Ohio. April 1965.

PREDICTING HARVEST MATURITY OF GREENHOUSE TOMATOES

William M. BrooksExtension HorticulturistThe Ohio State University

Much research has been done in recent years on predicting harvestmaturity for processing tomatoes. Methods studied have involved relation-ships of temperature, date of fruit set, or date when fruits reached agiven size. As the harvest labor problem becomes more acute and mechanicalharvesters become more refined, prediction of harvest maturity will becomemore important in the processing tomato industry*

A reasonably accurate method for quantitatively predicting harvestmaturity several weeks prior to maturity of greenhouse tomatoes would aidin managing labor supply and more orderly marketing.

In 1962 and 1963, a study was conducted in cooperation with a grower,Ellis D. Hoag of Elyria, Ohio. The purpose was to test methods for predict-ing the amount of fruit that will reach maturity during any given week of theharvest season* On Tuesday of each week throughout the growing season, thenumber of fruit set on each cluster of each plant was recorded. Fruit thesize of a pea was counted as being set. A 10-plant sample per house was usedduring the 1962 season and a 5-plant sample in 1963.

The number of fruit set each week was used to determine the weight offruit to be harvested during a future harvest period. An average of li ouncesper fruit and f>U days from fruit set to harvest maturity was used in the pre-diction calculations.

The results are presented in Figures 1 and 2. In general, the actualamount of fruit harvested each week followed closely the prediction pattern.However, there was a greater variance for the 1963 crop than the 1962 crop.This could have been caused by the smaller sample size in 1963*

The relationship of time of fruit set and harvest date is presented inTable 1*

Results' trom this limited study suggest that the volume of greenhousetomatoes to be harvested during any given week of the harvest season can bepredicted fairly accurately 7 to 8 weeks prior to harvest. Adequate samplingprocedures, accurate fruit counting, and experience in determining fruit settingappear most important in the success of the methods used in this study.

11

Table 1. - Relationship between time of fruit set (determined by developmentof "pea-aized" fruit) and harvest date of greenhouse tomatoes.

Harvest No. .

Spring Crop 1962

123U5678910n1213

Spring Crop 1963

123It5678910n1213Hi1516

Time ofFruit Set

Before Feb. 20Before Feb. 20Feb.Feb. 27March

March 27April

May

21-26- March 56-12

13-1920-26- April 23-910-1617-232U-301-7

Before Feb. 12Feb.

Feb. 27March

March 27April

May

13-1920-26- March 56-1213-1920-26- April 23-910-1617-232U-301-78-1U15-2122-28

Time ofHarvest

April 1-78-1U

15-2122-28

April 29 - MayMay 6-12

13-1920-26

5

May 27 - June 2June 3-9

10-1617-232U-30

April 6-1213-1920-26

April 27 - MayMay lt-10

11-1718-2U25-31

June 1-78-1]!15-2122-28

June 29 - JulyJuly 6-12

13-1920-26

3

5

Greenhouse Vegetable Research, Research Summary 1Ohio Agricultural Experiment Station Wooster, Ohio. April 1965*

SEEDING TOMATOES 70H XOSAIC RESISTANCE

Leonard J. AlexanderDepartment of Botany and Plant Pathology


Research has been underway several years to transfer resistance totobacco mosaic virus from lycopersicon peruvianum to tomato varietiessuitable for greenhouse, fresh market, arid processing culture. Duringthe studies, five pathogenic strains of tobacco mosaic virus (3M?) havebeen discovered* Some apparently undesirable linkages with the resistantgene or genes also have occurred-

In an earlier publication, Alexander (1963) showed that resistanceappeared to be governed by a single dominant resistant factor. At thattime, test plants were grown for the most part at 60 ° F* or slightly higher*Later results (d*+» 'xnpublished) indicated that when plants were grown atapproximately 80 ° F. or slightly higher, resistance was not dominant.

"When the work of breeding for TO7 resistance was first initiated, onlyone pathogenic strain of the virus was known. Shortly thereafter, however,it became evident that more than one pathogenic strain of the virus waspresent. cRitchie (195?) studied the problem and presented evidence thatthree strains of the virus were present in Ohio* Later work (McRitchie andAlexander 1963) demonstrated the presence of a fourth strain. Still laterevidence (data unpublished) has shown that a fifth strain is present. Eachtime a new pathogenic strain was found, it was necessary to find additionalgenes for resistance or to find a gene effective against one or more strainsof the virus.

In breeding crop plants for disease resistance, it is frequently expedi-tious to use the best adapted variety as a recurrent parent and set up aseries of backcrosses. This type of backcross program was used to breedtomato varieties for resistance to TMV.

In 1958* resistance to four strains of TMV was discovered in a selectionof PI 128650 of the species lycopersicon peruvianum. Since then, nine succes-sive backcrosses to plants of good varieties have been made« The designationof the resistant selection of L^ peruvianum is 12865Q~6Y-IV~12~1. Fortunately,it was found that progenies derived from this selection also carried resistanceto the new fifth strain«

The new undescribed strain, Strain V, produces mottled symptoms instandard varieties or breeding lines which appear to be completely suscept-ible to TMV. On the other hand, this strain produces necrosis or death toplants which are heterozygous for resistance when the plants are grown in atemperature regime of 80° F. or slightly higher. "When the plants are grown

15

under a temperature regime of approximately 60° F,, heterozygous plantsare for the most part healthy appearing*

The tomato mosaic resistant breeding lines presently being grown inthe experimental greenhouses are selfs from the eighth and ninth backerosses.Some appear to be homozygous for resistance but all appear to be segregatingfor one or more other characteristics.

During the backerossing program, certain undesirable characteristicsappeared in the backeross progenies more frequently than expected, Theseincluded: small fruit, excessive succulent growth -with poor setting,large cluster formations, smooth stems, and a pronounced tendency to growhorizontally* Because of these undesirable characteristics, the eighthand ninth backcrosses were made* It now appears that most of these un-desirable characteristics either have been or are being eliminated*

The pedigrees of the eighth and ninth backcrosses are similar exceptthat one has an extra backcross to good type. The following shows thepedigree of a progeny with nine crosses to good type. Ohio W-R 7 andOhio W-R 25 are abbreviated R-7 and R-25*

R-25 X ( R-25 x] ( (f(o W-R J X pa Fusarrum resistant greenhouseL V <J-\U- u ,

breeding line X Lycopersicon peruvianum, 128650JJX R-7 J X R-7 V X R-7 /

X R-7 X R-7 -1

Plants with this pedigree are growing in the greenhouse, have setexceptionally well, and have bloomed and set fruit earlier than eitherOhio W-R 25 or Ohio W-R 29• This is the first year that yield records willbe kept so it is too early to estimate accurately yield quality.

Both even-ripening and green shoulder fruit types are present, althoughit is hoped that the best selection will be an even-ripening type. At pre-sent, it is believed that a homozygous TM7 resistant selection can be made.Some of these selections appear to be homozygous for resistance to Strain ?.They may or may not be homozygous for resistance to Strains I, II, III, andIV.

16

Literature Cited

Alexander, Leonard J« 1963. Transfer of dominant type of resis*anoe tothe four known Ohio pathogenic strains of tobacco mosaic vSLruss(TMV) from Lycopersicon peruvianum to L. esculentum,Phytopathology 53 '• 869 • ""

HcRitchie, John J* 1957* Pathogenic strains of tobacco mosaoLc wirus ontomato.Phytopathology k7:23.

McRitchie, John J*, and Leonard J» Alexander* 1963* Host-specific:Lycopersicon strains of tobacco mosaic virus.Phytopathology £3:39U-398.

Greenhouse Vegetable Research, Research Summary 3LOhio Agricultural Experiment Station, Wooster, Ohio. ApriL.

17

STUDIES ON THE INHERITANCE OF TOBACCO MOSAIC VIRUS RESISTANCE IN TOMATO

Matteo P. Cirulli* and Leonard Jo AlexanderDepartment of Botany and Plant PathologyOhio Agricultural Experiment Station

Many workers have attempted to breed tomato varieties for resistanceto the tobacco mosaic virus diseaseo Thus far none have been successful.At the Ohio Agricultural Experiment Station, encouraging progress is beingmade in this direction* This paper describes initial studies on the in-heritance of resistance to several pathogenic strains of 1MV in F. progeniesunder two temperature regimes.

Methods and Materials

An inbred selection of Lycopersicon peruvianum, PI 128650, describedby McRitchie and Alexander (1963), was the original source of resistanceto 3MV. In breeding TMV resistant varieties, plants of this inbred selec-tion of L* peruvianum were crossed with plants of the domestic variety,using tEe embryo culture loethod described by Alexander (1956)*

Following the initial interspecific cross, the F hybrid was crossedto Ohio W-R Jubilee. This last cross was followed by five successive back-crosses to Ohio W-R 7. A homozygous resistant selection was isolated fromthe If2 generation of the last backcross and used for the resistant parent*This resistant parent was designated as HR-801. An inbred selection ofBonny Best was used as the susceptible parent*

Crosses between the resistant parent and Bonny Best and the reciprocalwere made. These two F-, hybrids were tested for resistance to the fourpathogenic TMV strains described by McRitchie and Alexander (1?63) and twoisolates of a fifth undescribed strain*

Plants were grown in U-inch clay pots under two temperature regimes*Thermostats were set at 60° F. and 80° F0 for low and higfc temperature regimes.In both cases, sunlight caused higher temperatures as shown in Figo lo

When the first true leaves were expanding, cotyledons and one leaf ofeach plant were inoculated by the rubbing technique. Inoculum was preparedby grinding infected frozen leaves of Nicotiana tabacum var* Samsun, anddiluting the extracted sap 1:3 with water, barborundum* 600 mesh, was addedto the inoculum before inoculation. The final disease record was taken 5

Notary International Foundation Fellow for 196U-65* Assistant inPlant Pathology, Institute di Patologia Vegetale, Universita diBari, Italy*

18

weeks after inoculation* Assays to N. glutinosa were made when visual symp-toms were doubtful.

Results

At the high temperature regime, isolates of the fifth undescribed strainof TMV produced necrosis, which often resulted in death of F- plants. Occasion-ally plants with the same pedigree exhibited necrosis at the low temperatureregime. Stem lesions also were noted occasionally on these plants.

Results of the tests are presented in Table 1.

At both temperature regimes, plants of L. peruvianum, PI 128650-6I-IV-1-12, and HR-801 were resistant to and Bonny Best was susceptible to all, strains-of the virus tested* No apparent difference existed in resistance and sus-ceptibility of the hybrids and their reciprocal.

In all cases tinder the low temperature regime, resistance was incomplete-ly dominant and with two exceptions, the diseased plants exhibited mottledsymptoms. The exceptions occurred with plants inoculated with Strains IIIand V-M, where necrotic symptoms occurred in a few plants.

Under the high temperature regime, resistance was absent in most cases.However, plants inoculated with Strain IV had approximately the same percent-age of resistant hybrid plants at both temperature regimes. With Strains IIand III, a few plants remained healthy. The symptoms produced on plants in-oculated with Strains I, 11, III, and IV were a typical mottle. This contrastswith symptoms on the plants inoculated with Strains V and V-M. In these cases>the symptoms were necrosis or death.

All plants of the resistant parent HR-801 were resistant to all TMV strainsunder both temperature regimes. Conversely, all Bonny Best plants were mottledwhen inoculated with all strains under both temperature regimes* No explana-tion is known for the occurrence of diseased plants when individuals of lycoper-sicon peruvianum were inoculated with Strain IV.

All uninoculated control plants remained healthy.

Summary

Under the low temperature, F plants and reciprocal crosses which derivedtheir resistance from lycopersicon peruvianum showed partial dominance wheninoculated with Strains I, II, III, and IV. In most cases, the plants snowedmottled symptoms» A similar reaction occurred when plants were inoculatedwith Strains V and V-M, except that diseased plants exhibited either mottledor necrotic symptoms.

At the high temperature regime, plants inoculated with Strains I, II,III, V, and V-M were susceptible in most cases. The incomplete dominance

20

was still evident when the plants were inoculated with Strain IV. StrainsV and V-M produced necrosis and, in many cases, death. Strains I, II,III, and IV produced mottling and deformation in most cases*

Literature Cited

Alexanderj Leonard J. 1956. Embryo culture of tomato interspecifichybrids. Phytopathology U6:6.

Alexander, Leonard J. 1963* Transfer of a dominant type of resistanceto the four known Ohio pathogenic strains of tobacco mosaicvixens (TMV) from lycopersicon peruvianum to L. esculentum.Phytopathology 53:869. ""

McRitchie, John J., and Leonard J* Alexander. 1963» Host-specificlycopersicon strains of tobacco mosaic virus. Phytopathology

Greenhouse Vegetable Research, Research Summary 1Ohio Agricultural Experiment Station, Wooster, Ohio. April 1965*

22

SOIL STERILIZATION IN RELATION TO CONTROL OF GREENHOUSE VEGETABLE DISEASES

Robert E* PartykaExtension Plant PathologistThe Ohio State University

Soil sterilization implies that all living organisms are killed in tliesoil* In practice this is not done in most cases.

To kill all living organisms in the soil with steam heat, the soil mustbe heated at high temperatures for long periods of time. This seriously affectssoil structure and may release various elements or micronutrients that arehighly toxic to living plants.

Disinfestation is a more descriptive term than sterilization,, Disinfes-tation implies that pathogenic organisms are killed or reduced so they will notcause economic plant losses* This is the goal in disinfesting the soil.

Soil disinfe station can be accomplished by the use of heat or soil fumigants*Bacteria,fungi, weeds, nematodes, isects, and viruses are the major factors con-sidered in soil disinfestation* The prime factor is degree of control*

Steam heat is the best method for soil disinfestation. The steamingmethod depends on the individual and the facilities in the greenhouse* Inmost cases, a permanent buried tile system is best* It is more expensiveat the start but cheaper in the long run.

Various chemicals can be used to partially disinfest the soil* Manyof these are specific for certain organisms. Some are strictly for thecontrol of nematodes, others will destroy fungi, weeds and nematodes, andsome will only destroy certain fungi. In most cases, these chemicals willnot equal steam dislnfestation but will reduce the disease-causing organismsso a satisfactory crop can be grown*

One factor to remember is that disinfested soil is open to recontamina-tion. Recontamination by a serious disease-causing organism is costly bothfrom the standpoint of treating the soil and plant losses*

The following factors should be considered when soil is to be disinfested:

1* Locate areas in the greenhouse where the disease problem exists beforeplants are pulled out* Mark the wires or posts with markers.

2. Identify the problem* Proper identification is necessary because timeof heating, depth of heating, chemical to use, and pretreatment of area areimportant to good control*

3* Be sure soil is of proper moisture content* This is important inareas where plants are dead* Dead plants do not remove soil moisture* If

23

a normal watering program is followed, these areas may be too wet at the endof the season. If the soil is too wet, heat and chemicals will not penetrateproperly or will require too much time* If the soil is too dry, the diseaseorganism may be in a resistant form and will not be killed by heat or chemical.Reduce watering in diseased areas or prework soil to dry, If too dry, addwater, Be sure soil is in good tilth.

li. Be sure soil is free of large lumps and undecayed organic matter*Most chemicals do not penetrate undecomposed plant material* Heat and chemi-cals penetrate large lumps slowly and may do a poor job of soil disinfestation*

5* If the disease problem occurs each year in the same place, the steamtile should be checked to be sure it is not plugged* A soil thermometer canbe used for checking these areas for proper treating temperatures*

6* Use accurate thermometers to check soil temperature. Inaccuratethermometers may result in tinder or overheating* When using chemicals, soiltemperatures must be 55° F. or above for best results. Many fumigants do notvolatilize properly at lower temperatures *

7, Steam tile lines should be 10-12 inches below the soil* Too muchsoil requires a longer period of steaming to do a good job. It may resultin over steaming of some areas*

8* Avoid oversteaming* Oversteaming in acid soils often releases largeamounts of soluble manganese that is highly toxic to some greenhouse tomatovarieties. Other nutrients may be released that will affect plant growth.Soil depth, length of lines, and length of steaming time should be considered*

9. Reoccurring pockets of Verticillium wilt are often associated withpoor soil disinfestation. However, infested soil or infested equipment maybe the source of recontamination*

10. Root knot nematodes may be difficult to eradicate if deep in the soil.Disinfesting usually does a good job to a couple of inches below the steam tileor to the depth at which a chemical is applied* If two crops of tomatoes aregrown and the soil is disinfested only once a year, the first crop may berelatively free of nematodes, Nematodes may begin to build up on the lowerroots* Then when soil is prepared for the second crop, these few nematodeswill be scattered in the upper layers of the soil and attack the new cropearly in the season. This often results in considerable damage halfwaythrough the season*

11* Walkways, cold walls, and areas around posts should receive specialattention, particularly if nematodes are located in these areas* Walkwaysshould have steam tile lines underneath to disinf est the soil* If nematodesdevelop in these areas, it may be necessary to retile or use chemicals atdepths greater than can be treated by steam*

12. Tools and equipment should be kept clean to avoid disease spreadin a crop and between crops* Clean tillage tools used in unsterilized soilbefore using in sterilized soil. Hand tools can be cleaned with a solutionof 1 part formaldehyde to 18 parts of water. For tools where water cannotbe used, removing the soil and plant material and washing with 70 percentalcohol will help. Water plus a detergent or the formaldehyde solutioncan be used for cleaning large tools, tractor-drawn equipment, pickingcarts, hand trucks and containers used from one crop to another.

13. Soil covers help do a better job of disinfestation, especiallyat the surface, and are especially important when some chemicals are used.All soil should be covered to be properly disinfested. Poor coverage andpoor soil treatment often result in recontainination. They may cause amore serious problem than if the soil was not disinfested. Soil disinfesta-tion kills many competing organisms and, if disease-causing organisms entertreated soil, they build up quickly because there is nothing to hold themback.

lU- Sweep or wash walkways before disinfesting soil. Infested soil onwalkways and headhouses may be a source of inoculum in a disinfested area.Other possible sources are outdoor crop soils, including home gardens ofemployees.

1$. Soil should be heated to 180° F. and held there for U hours todo a good job of soil disinfestation. This length of time is necessary tokill disease causing organisms in plant debris such as wilt and viruses.

Greenhouse Vegetable Research, Research Summary 1Ohio Agricultural Experiment Station, Wooster, Ohio. April 1965-

HETAIL MARGINS

M. E. CravensDepartment of Agricultural Economics and Rural Sociology


Retail margins on fresh tomatoes in 211| Ohio retail stores were analyzedfor the period March 27-June 17, 1961.

The proportion of the fresh tomato display given to greenhouse tomatoesincreased from 10 percent for the week beginning March 27 to more than 60percent for the week ending June 17* Most of the increase came from vineripe tomatoes* Tube tomato displays declined from U5 percent at the startto 30 percent at the end of the period.

About 20 percent of the stores carried greenhouse tomatoes the firstweek, compared with more than 90 percent by the end of the study period*

Average margins varied from 9-10 cents a tube for tube tomatoes toabout 18 cents a pound for U.S. No. 2 medium-large greenhouse tomatoes.Retail margins on vine ripe tomatoes were about 2.0 cents a pound morethan on U.S. No. 1 medium greenhouse tomatoes. Margins as a percent ofretail price varied from about 30 percent for U.S. No. 1 medium greenhousetomatoes to about i|8 percent for U.S. No. 2 medium-large greenhouse tomatoes.There were no significant differences between independent and chain retailstores with respect to margins on tomatoes.

Week-to-week variations in the average margin on greenhouse tomatoesfor all stores were minor (F3g. 1). Margins for other tomatoes varied morefrom week to week than those for greenhouse tomatoes. Wholesale and retailprices varied much more than margins on each type of tomatoes.

27

TOMATO QUAUTT STUDIES

M.E. CravensDepartment of Agricultural Economics and Rural Sociology


Members of consumer panels in Columbus and Cleveland were asked torate and compare the value of different types of tomatoes available duringthe greenhouse spring crop season. Greenhouse tomatoes were rated signifi-cantly higher on the quality rating scaleJL/ than vine ripe or tube tomatoes.On the average, consumers rated vine ripe tomatoes about 0.6 to 1.0 rankbelow greenhouse while tube tomatoes were rated 2.5 points below (Table 1).

Table 1.- Average ratings for tomatoes by consumer panel, Columbus,1957, 1958, 1959 and Cleveland, I960.

Type

Greenhouse pinkVine RipeTube

Columbus

1957 1958 1959(Average rating)

7.0 7.0 6.56.0 6.h 5-81*.5 U.5 U.O

Columbus Cleveland

1960(Average rating)

6.1 7.k6.0*ii.e

* Greenhouse small tomatoes

The difference in customer rating of the value of greenhouse and vineripe tomatoes from the 3 years ranged from 2.0 to 3-2 cents per pound whilethe differences between vine ripe and tube tomatoes ranged from U-9 to 6.2cents per pound. Greenhouse tomatoes were valued at 8.3 cents per poundmore than tube tomatoes by the panel members (Table 2).

1 / The rating scale was constructed as follows:

Poorest • | | || i " || | Bestever had • i « z b Hi ' S «o ly I b l y ever had

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Table 2. - Difference in value per pound as rated by consumers in Columbusin 1957, 1958, 1959 and in Cleveland, I960.

1957 1958 1959 I960 Average

(Gents per Pound)Greenhouse St Vine RipeVine Ripe & TubeGreenhouse & Tube

3.u.8.

392

2.06.28.2

258

.3

.9

.2

--8.5

258

.5

.9

.3

Since the samples and the stated differences were on a per pound basis,panel members understated the actual value differences between tube andother tomatoes as found in retail stores. Tubes weigh 12-lii ounces so theactual market difference should be about 10*0 cents (at average retail tomatoprices) plus 8.3 cents for quality differences or a total of 18*3 cents apound* Results of another study indicate that such a difference exists. Theactual average price difference in retail stores for the 1961 survey of 2lUstores was approximately 18.8 cents (Table 3)*

Table 3- - Average retail price for tomatoes in 2lk Ohio retail stores duringperiod March 27 - June 17, 1961 »*-

AverageRetail Price

Difference fromGreenhouse Medium

Tube Tomatoes

Vine Ripe Tomatoes

Greenhouse TomatoesU.S. No. l~Med.U.S. No. 1-SmallU.S. No. 2-Med-Large

27.

U6.238.838.1

(Cents per Pound)-18.8

- 6.7

0

I s!i

J.D. Brown, Ph.D. Thesis, 196UPer Tube—Equivalent price per pound 33*8^ if tube average weight13 ounces.

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Differences between vine ripe and U.S. No. 1 medium greenhouse tomatoeswere 6-7 cents a pound in the 1961 store survey and only 2.5 cents a poundby consumer evaluation in the Columbus panel. This suggests that panel mem-bers were less critical of vine ripe tomatoes than indicated by market pricedifferences. Perhaps appearance and more knowledge of greenhouse quality inthe retail store accounts for this greater than expected difference. Similarly,the consumer panel indicated a difference in value of 5*9 cents a pound betweenvine ripe and tube tomatoes while the retail store study showed a price differ-ence of 12.1 cents a pound* Again, if an adjustment is made for the weightof the tube in the retail store, the difference would have been approximately5*7 cents or the same at retail as for the panel.

The comparisons above indicate that the consumer is aware of differencesin quality and quantity between tubes and other tomatoes.

Another comparison of interest was consumer reaction to greenhousetomatoes harvested at the pink-ripe or the pink-green stage. In each casethe riper tomatoes were rated higher but only in the large tomatoes wasthe difference statistically significant. For large greenhouse tomatoes,the tomatoes picked at the riper stage were valued at about 2.3 emits apound more, even though alT were ready to eat when delivered to the panelmembers (Table li).

Table 1*. - Comparisons of differences in panel ratings and retail value forripeness at harvest and size of tomatoes, Columbus, 1959-

Greenhouse Tomatoes

Harvested Fink-GreenHarvested Ripe

Difference betweenRipe and Fink-Green

Large Medium

(Average6.7 6.57-1* 6.7

Small

rating)6.06.k

(Cents per Bound)

2.3 0.7 1.3

DifferenceLarge & Small

(#Ab. )2.33*3

_

U.S. No. 1 small tomatoes were valued at 2.3 to 3*3 cents a pound lessthan U.S. No. 1 large by panel members (Table U). As with vine ripe tomatoes,it appears that after panel members compared tomato value they were lesscritical of the small greenhouse tomatoes than indicated by the price differ*ence found in the retail stores.

The major characteristic in tomato preference was "flavor.11 The secondmost important was "texture." "Appearance11 was a factor where greenhousetomatoes were rated higher than competitors.

Greenhouse Vegetable Research, Research Summary 1Ohio Agricultural Experiment Station, Wooster, Ohio. April 1965.

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CONSUMER PREFERENCES FOR GREENHOUSE TOMATOES

P. R. Thomas and E. J. RoyerCooperative Extension ServiceThe Ohio State University

A study was conducted during May 196U to determine whether consumerscould identify greenhouse and competing types of tomatoes. The purpose wasto learn what consumers know about tomatoes. The study results may givedirection to greenhouse tomato growers on whether to increase promotion,expand markets, give more attention to in-store displays, or other market-ing efforts.

The study was conducted during the third week in May when greenhouseand competing tomatoes were in good supply* A total of 860 shoppers wereinterviewed in Cleveland, Columbus, and Cincinnati. In each city, inter-views were conducted in two stores—one in a high income area and the otherin a medium to low income area.

Shoppers were interviewed as they entered the produce area. Eachinterviewee was shown three types of tomatoes: greenhouse, vane-ripe, andtube i-/, but identity of the tomatoes was not revealed until the inter-view was completed. Interviews averaged approximately 5 minutes each.

— Greenhouse tomatoes can generally be identified by the calyx or greenstem left on the tomato at harvest.

Vine-ripe tomatoes are grown outdoors, mainly in Florida and Texas,and harvested in winter and spring* They arc harvested usually on theturn from mature-green to a pink color.

Tube tomatoes are grown outdoors in Mexico and some southern states,picked at the mature-green stage, shipped to consuming areas, and ripenedin storage. They are then repacked in tubes containing three or fourtomatoes. "Repacked" is another term used in the wholesale trade.

33

Questions and Responses

Question 1, Do you purchase tomatoes throughout the year? Is thereany special reason why you don't purchase tomatoes throughout the year?

About 75 percent of those interviewed said they purchased tomatoesthroughout the year. Reasons given for not purchasing tomatoes were:(1) price too high, (2) tomatoes lacked taste, and (3) grow own tomatoes*

Question 2. What kind of tomatoes do you call these? Here theinterviewee was shown the three types* Approximately Ul percent of the860 interviewed correctly identified the vine-ripe tomato, 57 percentthe tube tomato, and 1|6 percent the greenhouse tomato.

The next three questions were to determine if the shoppers identi-fied the tomatoes by guessing or by actual knowledge.

Question 3* How do you identify a tube tomato? Of the 860 peopleinterviewed, 372 or U3 percent correctly identified the tube tomato, 11percent gave incorrect responses, and 1*6 percent didn't know. In attempt-ing to identify this tomato, the size, color, appearance, and containerwere the most frequent comments.

Question Iu How do you identify a vine-ripe tomato? About 26 percentcorrectly identified the vine-ripe tomato, 28 percent gave incorrect responses,and Ii6 percent had no idea* The most frequent replies were color, appearance,stem, and "like homegrown."

Question 5» How do you identify a greenhouse tomato? The ability ofshoppers to identify greenhouse tomatoes was not as great as in the case oftube tomatoes* However, more shoppers correctly identified greenhousetomatoes than vine-ripe. Approximately 3k percent of those interviewedcorrectly identified the greenhouse tomatoes, 25 percent gave incorrectresponses, and lil percent had no idea.

Question 6. When asked which type of tomato on the interview displaytable they liked best, 1±28 or 50 percent indicated a preference for vine-ripe, Ii5 percent preferred greenhouse, and 3 percent tube tomatoes* Whenthose who showed a first choice for the vine-ripe tomatoes were asked why,138 said because of taste, 5l said appearance, 25 said color, and 25 saidthey seemed firmer than the other two types. Other answers were becausethe vine-ripe tomato was grown outside (15), size (7), price (U), juicier(U), and other reasons.

Those who preferred greenhouse tomatoes said because of taste (103),appearance (76), color (53 )> seemed riper (13), firmer (9), larger size(7), fresher looking (U), texture (3)> and other reasons. Many of thereasons for liking greenhouse tomatoes were similar to reasons given by

those who preferred vine-ripe. Only 11 people of the 27 that preferredtube tomatoes gave reasons. Six mentioned size as the reason for theirpreference.

After the shopper indicated which type of tomato was preferred in thefirst part of question 6, price signs were placed behind the three tomatotypes as follows: U9#/lb. for greenhouse tomatoes, 39#/lb. for vine-ripe,and 33#/lb. for tube tomatoes* The shopper was then asked to indicate whichtype she thought was the best buy. The results were: U8 percent chosevine-ripe, 37 percent chose greenhouse, 8 percent chose tube, and 7 percentdid not indicate a choice.

Price (88), taste (81), appearance (59)* firmness (10), and color (9)were the main reasons given for choosing vine-ripe. Greenhouse tomatoeswere preferred for taste (67), appearance (50), pay for what you get (21),price no factor (10), and color (9). Tube tomatoes were preferred forprice (26) and size (6).

When price was included in the choice consideration, a slight decreasein first preference was noted for vine-ripes (-3$) and a moderate decrease(-18$) for greenhouse tomatoes* Only 27 persons or 3 percent said they likedtube tomatoes best when prices were not shown. However, 71 or 8 percent saidthey thought tube tomatoes were the best buy when prices were shown.

Question 7* When asked if they noted any difference between tomatoespurchased at the time of the study (May 19610 and those purchased in summer,four out of five interviewed said yes. The most common answer was thatsummer tomatoes taste better and are fresher* From the answers it appearedthat much of the reasoning was psychological and based on the belief thattomatoes grown outdoors in the summer "just had to be better I"

Question 8. Did you purchase any tomatoes today? About 36 percentreplied yes.

Summary and Conclusions

Only one-third of those interviewed could identify correctly the green-hou^e tomato. Of those who did correctXy identify the greenhouse tomato,most mentioned color. The second most important factor in greenhouse tomatoidentification was the stem, with 23 percent of those giving the correctidentification mentioning the stem or calyx*

35

"When asked which they liked best, the vine-ripe tomato ranked firstwith and without price as a consideration. Txls as true in all threecities.

Price is a factor and affects consumers' decisions about buying toma-toes* Consumers also have a high image of the flavor of tomatoes they eatduring the summer.

It is evident that many consumers do not know one type of tomato fromanother. In fact, it appears consumers are indifferent as to what a typeof tomato is called*

This study shows the vine-ripe tomato is a strong competitor of thegreenhouse tomato* Consumers buy on the basis of how they think a tomatomil taste. Their selection is based primarily on color and appearance ofthe tomato at th*j market,,

Greenhouse Vegetable Research, Research Summary 1Ohio Agricultural Experiment Station, Voostcr, Ohio. April 1965.

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