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T02.001The Relation between Flowering Habit and the Fruit Setting of the Kumquat

Nakao, Y.1; Kato, M.1; Morita, T.1; Tuchiya, S.1; Kawase, K.21Meijo University, Takagi, 486-0804, Kasugai, Aichi, Japan2Kawase Professional Engineer Office, Sakura1, 889-2154, Miyazaki, Japan

Kumquat (Fortunella crassifolia Swingle) is originally from china and has cultivated for more than a 1,000 years. It is cultivated from 1826 in Japan and has become a popular fruit. The fruit is used for table use, Chinese medicine, processed food materials, and the tree itself can be used for ornamental display. Kumquat is a perpetual flowering and there are a few times full blooms during the summer in Japan. The harvest period is mainly from December to March. We’ve researched in details about the relationship of flowering habits and fruit settings. In addition, we revealed both the effects of flowering habits and fruit settings that result from the flower thinning. The flowering started at about 26 degrees Celsius. The flowering times were different for every individual Kumquat, and they varied from 3-5 times every 2 weeks between flowering periods. There were small flower buds on the peduncle during the first flowering, but the growth of these flower buds did not start soon, and later started after flowering or fruit abscission. Kumquat fruit that is derived from the first flowering period are usually larger than the later flowering periods. If the first flowers are removed, however, the number of flowering increases the second flowers and the third fruit becomes significantly larger as opposed to the non-thinning. The thinning that occurs in fruit growing is generally an effective method for quality control within the year it occurs, and especially for flower bud formation the following year. Similarly, the thinning of Kumquat control a number of flowers and fruit set within in a same year.

T02.002Fruit Set in Orange (Citrus xsinensis (L) Osb.) with Phytohormones in Tamaulipas and Nuevo Leon Mexico

Galvan, J. J. L.1; Valdez, L. A. A.2; Reyes, V. M. S.3; Salazar, O. S.41Universida Autonoma Agraria Antonio Narro, Calzada Antonio Narro 1923, Obregon Norte 717, 25000, Saltillo, Coahuila, Mexico2CIQA, Mexico3UAAAN, Mexico4Universidad Autonoma de Tamaulipas, Mexico

The lacing the fruit needs the conjunction of two factors: an initial stimulus that causes the growth of the ovary and their ability to accumulate metabolites and adequate availability of these. This availability is critical during the abscission and determines final fruit set of fruit. It’s set, or tie-flowering fruits and not the fac-tor determining the crop in citrus (Guardiola, 2000). In the absence of research on the use of growth regulators in the North East of Mexico and the low rate observed in the orange tie, the present research work aimed to evaluate the effects of two complex natural hormone (auxins, gibberellins and cytokinins) and 2,4 - D (dichlorophenoxyacetic) in the tie, fruit yield and quality of two orange cultivars and to identify and quantify the gibberellic acid (GA3) to relate the endogenous content with the exogenous applications. Four experiments were conducted in a design in a randomized complete block with five treatments and four replications arranged in a split plot corresponded to the large plot and the plot cultivars girl found in the treatments. The fruit weight showed a significant difference between the proportions hormone, with an average weight of 325.78 g in ‘Washington’ and 330.67 g in ‘Thomson’, representing values greater than those reported (200-250 g) by Agustí (2003). Auxins (32.2 ppm), gibberellins (32.2 ppm) and cytokinins

CITRUS

T02(83.2 ppm) in these proportions possible to increase the berthing of the fruit yield and quality under the conditions described. According to the results of this experi-ment in the Central zone of Tamaulipas Mexico the best date for the application of 2,4-D, orange varieties ‘Washington navel’ and ‘Thomson’ is in full bloom to favorably affect the performance.

T02.003Heavy Pruning Effects on Flower Buds Formation of Citrus microcarpa Bunge and Fortunella margarita Swing

Lai, Y.1; Lin, Y.2; Chen, I.21Taishan Township Office, 322f.; Sec. 1, Mingzhi Rd.; Taishan Township, 243, Taipei, Taiwan2National Taiwan University, Taiwan

In Citrus, like most subtropical fruit tree, low temperature often been considered as an inducement to release bud dormancy and enhance flower bud formation, while high temperature is reported to inhibit flower formation contrarily. However, kumquat (Fortunella spp.) and calamondin (Citrus microcarpa Bunge) are found in different situation. In Taiwan, blooming period of kumquat usually occurs in high temperature season, and shoots developing under low temperature condition will be vegetative, shows high temperature may improve flower bud formation pro-cess. A similar result is also shown in potted kumquat which held at 35/30 °C (day/night temperature) began to bloom after 2 weeks and had greater number of flower, while those in 25/20 °C and 20/15 °C failed to bloom in experimental period. Flower bud formation in calamondin is very fast. Calamondin with new flush grown under 25 °C might flower when reach three week old of age, no matter they were in high or low temperature thereafter, but higher temperature treatment induce greater number of flower. It shows temperature might not be an important factor to influence flower bud formation in calamondin. Since calamondin is an interspecific hybrid of kumquat and small fruit mandarin, its flowering behavior may be influenced by both of them.

T02.004Integrating Cover Crops to Enhance Sustainability in Banana and Citrus Cropping Systems

Lavigne, C.; Achard, R.; Tixier, P.; Lesueur Jannoyer, M.CIRAD, Petit Morne BP 214, 97285, Le Lamentin, Martinique

In Martinique (FWI), because of the susceptibility of insular environment, the demand from society and policy-maker is high in sustainable and environmentally friendly fruit production systems. In tropical wet areas, weed management is cru-cial, but it remains difficult without herbicides. Furthermore, herbicides become the most important pesticide in banana and fruit fields; thus developing herbicide free alternatives is a priority. Cover cropping systems constitute the most promising option. Beside weed control, their ability to reduce runoff and soil erosion, water and nutrient competition, to host pests and auxiliaries, to preserve biodiversity are key services that may be provided by cover crops. A multi step and multicriteria grid was built to select the ideal cover crop. We tested it on banana and citrus orchards. In the first step, cover crops are selected on the basis of their climate suitability, seed availability, technical suitability, non invasive status, and perennial under the main crop. In the second step, we assessed the agronomic performances of 24 cover crops species in field conditions. We measured their specific traits (es-tablishment, covering rate, perenniality, biomass production, root depth, nutrient uptake or recycling, regrowth after mowing…). In the last step, we defined specific objectives to be reach in terms of ecological outputs for each cropping systems spec-ifications. We designed cropping system prototypes with the most relevant cover crops. In citrus orchards, grasses, characterized by a high covering index associated with a low biomass production, were selected but auxiliaries hosting services were poor. In banana fields, grasses were intercropped and the nitrogen competition between cover crop and banana plants was assessed using the SIMBA simulation model. As a conclusion, we showed that the concept of ‘ideal cover crop’ is useful to select cover crop species and to design efficient cover cropping systems.

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T02.005Partial Root Drying of Lemon under Semi Arid Conditions of North of Minas Gerais

Coelho, E. F.1; Coelho Filho, M. A.1; Oliveira, P. M.21Embrapa Cassava & Fruits, Rua Embrapa s/n, 44380-000, Cruz das Almas, Bahia, Brazil2EPAMING Norte de Minas Gerais, Brazil

This work aims to evaluate partial root drying technique for lemon cv. Tahiti under conditions of climate and soil of North of Minas Gerais in sandy soil. The experi-ment followed a random block design with nine treatments and four replications. The partial root drying was accomplished by turning on and off water emission from lateral lines that were located at both sides of each crop row of the plot at dif-ferent time intervals (7 and 15 days). Treatments consisted of irrigation deficits of full irrigation (FI), with application of 75% of FI as partial root drying at intervals of 7 days (T1) and 15 days (T2) in all phenological phases; application of 50% of FI as partial root drying at intervals of 7 days (T3) and 15 days (T4) in all phe-nological phases; application of 75% of FI during phases I and II and 50% of FI during phase III, as partial root drying at intervals of 7 days (T5), 15 days (T6) in all phases; application of 75% of FI during phase I and 50% during the remaining phases, as partial root drying at intervals of 7 days (T7) and 15 days (T8). Results showed that irrigation with partial root drying management may be done with any of the treatments. The larger yields and water use efficiencies were obtained for treatments T7 and T8 (reduction of 25% total irrigation every 7 or 15 days during flowering followed by reduction of 50% of total irrigation every 7 or 15 days in phases II and III). The variance analysis did not detect effect of treatments on the physiological variables leaf transpiration, stomatal condutance, temperature and relative water content. A reduction of transpiration and stomatal condutance was detected for treatments T1, T2, T3 and T4 related to T9 in the phase I.

T02.006Partial Root Drying as Strategy for Water Use Optimization in ‘Tahiti’ Lime Orchard under the Semi-Arid of Bahia State

Sampaio, A. H. R.1; Coelho Filho, M. A.2; Coelho, E. F.2; Daniel, R.1; Machado, V. V.1; Carvalho, G. C.1; Sant’Ana, J. A do Vale3; Santana Junior, E. B.11Federal University of Bahia Reconcavo, Center for Agricultural Science, Environmental and Biological, s/n, 44380-000, Cruz das Almas, Bahia, Brazil2Embrapa Cassava & Tropical Fruits, Brazil3Federal University of Lavras, Brazil

The management of irrigation with partial root drying (PRD) was tested in orchard of ‘Tahiti’ lime in semi-arid conditions of Iaçu-BA. Six treatments were evaluated: T1, T2, T3 and T4 received 50% of ETc, T5 -100% and T6 - 75%. A microsprin-kler was installed per plant and its location to the plant was changed by wetting opposite sides of the root system alternately for treatments with a water deficit of 50%. The interval for changing the wetting locations was 7, 14 and 21 days for T1, T2 and T3, respectively. Irrigation was fixed in just one side for the treatment T4. Irrigation was fixed with 100% of Etc as water supply in the control treatment, T5. In case of T6, one microsprinkler per plant worked during 21 days, followed by two emitters per plant which worked during the same interval along crop cycle. There was no statistical difference (p<0.05) by Scott Knott test for the variable fruit production. The treatments T5 and T6 obtained the highest yield with 23.16 and 22.49 t∙h-1, respectively. Treatments with deficit had average production reduced 30%. Switching sides of irrigation had no benefit over treatment with the deficit in only one side. Although there was no statistical difference in efficiency of water use, physiological indicators showed that the treatment in water deficit developed mechanisms to reduce transpiration.

T02.007Effect of Girdling in Gas Exchange, Carbohydrates and other Secondary Metabolites of Leaves from Low Zn ‘Valencia’ Orange Trees

Melgar, J. C.; Cevallos-Cevallos, J. M.; Syvertsen, J. P.; Reyes-de-Corcuera, J. I.Citrus Research and Education Center, University of Florida / IFAS, 700 Experiment Station Road, 33850, Lake Alfred, Florida, United States

Citrus leaves on phloem-girdled branches may develop symptoms similar to Zn deficiency or diseases like Huanglongbing (HLB). We studied the changes in sec-ondary metabolites, carbohydrate accumulation and gas exchange parameters after girdling one-centimeter diameter branches on thirteen-year-old ‘Valencia’ sweet or-ange trees with and without leaves with Zn deficiency symptoms. There were four combinations of with/without Zn deficiency symptoms and with/without girdling. Principal components analysis (PCA) of metabolites analyzed by GC-MS partially grouped Zn deficient leaves separate from girdled and control leaves. L-proline, simple sugars and sugar alcohols were higher in Zn deficient and girdled samples. Carbohydrate accumulation after girdling caused decreases in CO2 assimilation and water use efficiency in healthy appearing trees but not in trees with Zn deficiency symptoms. Proline may have played a role enhancing photosynthesis activity and other metabolic implications. Similar increases in L-proline were observed in leaves from HLB affected trees (with symptoms similar to Zn deficiency) but further studies are needed.

T02.008Factors Affecting Rind Oil Content of Lemon [Citrus limon (L.) Burm. F.]

Barry, G. H.; Coetsee, H. E. Stellenbosch University, Department of Horticultural Science, P. Bag X1, Matieland, 7602, Stellenbosch, South Africa

Among the controllable and non-controllable factors affecting rind oil content of lemons, genetic (scion, rootstock) and environmental (growing conditions, canopy microclimate) factors play the most important role. ‘Limoneira 8A’, fol-lowed by ‘Cicily’, ‘Lisbon’ and ‘Genoa’ had the highest rind oil content, whereas ‘Villafranca’, ‘Messina’ and ‘Yen Ben Lisbon’ had the lowest. Rind oil content of ‘Eureka’ lemon was disappointingly low. Seedless cultivars, ‘Eureka SL’ and ‘Lis-bon SL’, had ~18.0% higher rind oil content than the seeded cultivars from which they were derived. Fruit from lemon trees budded on non-invigorating rootstocks, e.g. X639 (a Cleopatra mandarin × Trifoliate orange hybrid), had the highest rind oil content, whereas rind oil content was low on invigorating rootstocks, e.g. rough lemon. South Africa has a diverse climate, and rind oil content from fruit produced in a hot, arid growing region (Upington) had the highest rind oil content, whereas fruit from relatively warm regions (Malelane and Marble Hall) ranked second, and rind oil content of fruit from a cooler region (Karino) was intermediate. Rind oil content from a cold growing region (Vaalharts) was the lowest. Regression analysis between rind oil content and cumulative heat units revealed a positive linear relationship, and, in general, rind oil content increased with increasing heat unit accumulation. Following the sampling of fruit from different positions in a tree’s canopy, light exposure was found to affect rind oil content of ‘Eureka’ lemon fruit. Fruit borne on the outside of trees, higher in the tree, north-facing or not within the hedgerow had the highest rind oil content. PAR data supports the hypothesis that rind oil content is correlated with light exposure. Therefore, the choice of scion cultivar and rootstock in a given growing region, together with judicious pruning to optimise light penetration into a tree’s canopy, contribute to enhanced rind oil yields.

T02.009Molecular and Morphological Characterization and Evaluation of Turkey Citrus Genetic Resources

Tuzcu, O.1; Yesiloglu, T.1; Anil, S.2; Uzun, A.3; Tepe, S.4; Tan, A.5; Aka-Kaçar, Y.1; Yildirim, B.1; Gulsen, O.6; Polat, I.4; Turgutoglu, E. 4; Aykas, L.5; Kafa, G.3; Kurt, S. 4; Kamiloglu, M.1; Incesu, M.1; Seday, U.2; Demir, G. 4; Canan, I.3; Arslan, A.4; Agsaran, B.4; Bayram, S.4; Ozkarakas, I.5; Ulas, , M.1; Çelik, N.4; Eryılmaz, Z.4; Eski, H.4; Bengü, K.4; Îkten, H.4

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1University of Cukurova, Faculty of Agriculture, Horticulture Department 01100, Balcali, Adana, Turkey2General Directorate of Agricultural Research of the Ministry of Agriculture, Ankara, Turkey3Alata Horticultural Research Institute Mersin, Turkey4Batı Akdeniz Agriculture Research Institute, Antalya, Turkey5Ege Agricultural Research Institute İzmir, Turkey6University of Erciyes, Faculty of Agriculture, Horticulture Department Kayseri, Turkey

Citrus and related genera have broad range of genetic diversity including many fam-ily, genera, species and cultivars in the subfamily Aurantioideae. Although Anatolia is not a geographic origin center for Citrus and related genera, it has accumulated a considerable diversity during 2000 years of existing. For this reason, it could be considered as a second degree gene center. Genetic variation in Citrus species is generally limited. The basic limiting factors are apomixis and high tendency to poliembriony. The value of plant genetic resources is expressed with the wealth of plant material used in breeding rather than the number of collected and protected material. Therefore it is crucial to register citrus genetic resources, sanitation from virus-like diseases, establish new collected orchards, and present the plant mate-rial to breeders for new varietal development. In this project, research activities on the collection, characterization, conservation and evaluation of ‘Tuzcu Citrus Collection’ (TCC) which is the most important Citrus genetic collection of Turkey were undertaken. This collection includes 774 genotypes introduced from different countries and from native selections and obtained from breeding programs and sur-vey works. At the end of the project; the inventory of existing resources completed and recorded in database; morphological and molecular (SSR and SRAP markers) characterization have been carried out; sanitation process has been started.

T02.010Performance of the ‘D. João’ Sweet Orange in Algarve

Duarte, A.1; Nunes, S.1; Sustelo, V.1; Gomes, C.2; Matinhos, P.1; Mendonça, A.3; Tomás, J. C.21Universidade do Algarve, ICAAM, Campus de Gambelas, Edif. 8, 8005-139, Faro, Portugal2Direcção Regional de Agricultura e Pescas do Algarve3Frusoal - Frutas Sotavento Algarve

The ‘D. João’ sweet orange is an old Portuguese cultivar firstly described by Mira Galvão in 1943 and widely cultivated in Portugal in the past. The proper characteriza-tion of this cultivar has not been done yet and its propagation has been progressively reduced due to the introduction of new cultivars. However, the prestige of this cultivar among farmers has resulted in the survival of some orchards, avoiding the total re-placement of ‘D. João’ by other sweet orange cultivars The characteristics of ‘D. João’ are close to the ‘Valencia late’, but some differences are pointed out by farmers and also confirmed by our present work. The studied cultivar produces late season sweet oranges harvested during the summer. The ripening normally occurs in April/May, but the fruits can remain on the tree until the end of the summer without any signifi-cant loss of juice content. The acceptance by consumers is usually very good, making possible the commercialization of ‘D. João’ as a fresh fruit during a long period of time. The high juice content of the orange and the possible stay of the fruit on the tree during the summer are both important factors for the juice industry. A brief char-acterization of the cultivar was done. We also evaluated the fruit quality (fruit size and colour, peel thickness, juice content and ºBrix) during the maturation period by labo-ratorial analysis. The study was complemented with an organoleptic analysis by mean of a panel of consumers. Due to its high performance, we conclude that ‘D. João’ is a sweet orange cultivar with new promising perspectives not limited to Portugal. A new interest in its propagation is actually already starting. This case study is a relevant example showing the importance of maintaining genetical resources for the future.

T02.011Development of Chemical Inducible Deletion Technologies for Citrus Marker-Free Transformation

Yang, L.1; Li, L.1; Xie, Y.1; Ye, Z.2; Deng, Z.11Hunan Provincial Laboratory of Crop Germplasm Innovation and Utilization, National Center for Citrus Improvement (Changsha), Hunan Agricultural University, 410128, Changsha, Hunan, China2National Key Laboratory of Crop Genetic Improvement, National Center for Vegetable Improvement (Central China), Huazhong Agricultural University, Wuhan, 430070, China

Transgenic breeding is an important complement to conventional breeding, and antibiotic or herbicide resistant selective genes are widely used as markers in the

transformation experimentation for the selection of transgenic regenerants from the wild type tissues. However, the potential hazards on ecological environment and human health of such marker genes remaining in the transgenic plants have caused common social worries and concerns. The establishment of marker-free transformation system is of great significance to improve the safety of genetically modified crops. In the present study, a chemical-inducible auto-excision marker free vector system with Cre/loxP site-specific recombination system and an induc-ible expression system XVE was used in citrus. In this vector, three elements includ-ing the trans-activator XVE, recombinase gene Cre and the coding sequence of the neomycin transferase II were located between the two direct repeats of loxP. Upon induction by ß-estradiol, recombination between two loxP sites leaded to excision of cre, nptII and XVE. Then the gfp gene was put directly downstream the CaMV 35S promoter, and only in this case, it could be expressed. Agrobacterium-mediated transformation was carried out on sweet orange transformation with above vector and the gfp expression was detected by visualizing green fluorescence. The result indicated that marker gene excision in this vector could occur in citrus transfor-mants. When regenerated buds reached to 2-4 mm, they were cut and transformed to chemical-inducible medium (MS+ 1mg/l 6-BA + 4 μM ß-estradiol). After reach-ing 1 cm, shoots were cut and subcultured on chemical-inducible medium for an-other 30 days. Molecular detection and fluorescence observation indicated that different gene recombination and partially excisions existed in various transgenic citrus clones. The complete excision of marker genes were detected in 3 of the 80 transgenic clones. The suitable conditions for the induction of removing marker genes were discussed.

T02.012A Copia-Like Retrotransposon Activated during Protoplast Fusion Are Polymorphic among Varieties in Citrus

Haijun, M.1; Guoliang, W.1; Xiuxin, D.21College of Horticulture, Henan Agricultural University, Wenhua Road, 95, 450002, Zhengzhou, Henan, China2National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China

Retrotransposons play an important role in genetic variation and genome evolu-tion. In the present study, one fragment containing part of the POL coding region of copia like retrotransposons, named Kumquatee1, was isolated from Fortunella hindsii, a close relative of the genera Citrus, and homologies were found in Citrus and its relatives. Southern blotting showed that Kumquatee1 presented in very high copy number in Citrus and its relatives. To investigate the transposition of Kumquatee1, a population of regenerated plants from ‘Valencia’ Orange + Kum-quats (C. sinensis +Fortunella crassifolia) somatic hybrid was analyzed. An increase in the copy number of Kumquatee1 was observed. It indicated that Kumquatee1 was activated during the progress of protoplast fusion. Furthermore, the cloned fragment of Kumquatee1 was used as a probe to detect genetic variation among varieties of sweet orange. Three polymorphic loci were observed in 15 sweet orange cultivars, which implied that Kumquatee1 might be involved in the formation of sweet orange varieties.

T02.013How to Manage Weeds with a Reduced Use of Herbicides: Cover Crops in Mandarin Orchard in Guadeloupe

Lebellec, F.1; Damas, O.1; Tournebize, R.2; Vannière, H.3; Ozier Lafontaine, H.2; Lesueur Jannoyer, M.41CIRAD, UPR103, 830 Route du Bouchu, 97119 Vieux-Habitants, Guadeloupe2INRA, Domaine de Duclos, 97170 Petit Bourg, Guadeloupe3CIRAD, TA B-103/PS4, Boulevard de La Lironde, 34398 Montpellier, France4CIRAD, Pram Petit Morne, Bp214, 97285 Le Lamentin, Martinique

Weed management is an important point of the citrus production in tropical wet area. Thus, the use of herbicides regularly sprayed on the whole farm is the most common practice. Introduction of cover crops on these orchards could be an in-

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teresting alternative. A multi criteria evaluation grid was built to select an ‘optimal’ cover crop with specific criteria related to local climate, plant biology and seed availability. The very first aim of cover crops is to control weeds, but benefits in re-duced erosion and other environmental services are also expected. This study con-sists in quantifying the effects of a cover crop introduction on 3 years old mandarin orchards. In our conditions, the cover crop system is designed in order to obtain a perennial association and to limit as much as possible the number of chemical interventions. For 3 years two modalities have been compared: (i) farmer practice, mandarin orchard with herbicide (Glyphosate) every 2 months, and (ii) mandarin orchard in association with Neonotonia wightii. No more herbicide was sprayed on the associated plot while the bare ground plot received 6 herbicides a year. We measured the cover crop - tree water competition and the environmental impacts through Indigo® indicators. Despite some difficulties in setting up the system N. wightii suppressed efficiently weeds after 6 months. Meanwhile, no significant dif-ference in the predawn water potential of the soil has been revealed between the two modalities. So water stress is not induced by the cover crop in our citrus orchard. After 3 years of experimentation, no impact on the performance of the field has been observed and this new practice is in transfer to farmers.

T02.014Tylenchulus semipenetrans Biotypes in Six Citrus-Producing Provinces of South Africa

Mashela, P. W.1; Mafeo, T. P.1; Pofu, K. M.1; Shemilis, A. H.21School of Agricultural and Environmental Sciences, University of Limpopo, Department of Soil Science, Plant Production and Remote Sensing, Private Bag X1106, 0727, Sovenga, Limpopo Province, South Africa2University of Kwazulu-Natal, Private Bag X01, Scottsville 3209, Pietermaritzburg, South Africa

The citrus nematode (Tylenchulus semipenetrans) is the casual agent of slow decline of citrus, characterized by, inter alia, small fruits. Tylenchulus semipenetrans has three biotypes, viz. poncirus, mediterranean and citrus. Without support of empirical data, nematologists presumed previously that the South African citrus nematode biotype was the mediterranean type. This assumption resulted in widespread use of nematode-resistant rootstocks that were non-host to the mediterranean biotype, with the selected rootstocks performing poorly under various conditions. A study was initiated to determine the South African citrus nematode biotype using three differential hosts, viz. rough lemon (Citrus jambhiri), trifoliate orange (Poncirus trifoliata) and olive (Olea europaea L.) from six citrus-producing provinces, viz. Limpopo, Mpumalanga, North West, Eastern Cape, Western Cape and Kwa-Zulu Natal. A sampling farm site per province was selected at random, with roots be-ing collected from 20 randomly selected trees. Nematode eggs and juveniles were extracted on site by shaking the roots vigorously, collecting the aliquot and trans-porting in cooler boxes to the laboratory for further processing. Three-month-old differential host seedlings were inoculated with approximately 10 000 J2s and arranged in a randomised complete block design with 15 replicates. At harvest, 120 days after inoculation, isolates from each province had the reproductive factor (RF) of less than one on olive, but greater than one on rough lemon and trifoliate orange. The RF less than one suggested that T. semipenetrans failed to reproduce and develop on olive, whereas that of greater than one suggested that the isolates reproduced and developed on the other two hosts. In conclusion, the South African citrus nematode biotype is poncirus, which implies that P. trifoliate which is widely used is not a suitable rootstock.

T02.015Movento�, Citrus and Honey Bees: Bee Safety Demonstrated in a Large Scale Cooperative Field Study

Rogers, R. E. L.1; Williams, G. R.2; Lam, C.3; Fischer, D. L.11Bayer Cropscience, 2T. W. Alexander Drive, 27709, Research Triangle Park, North Carolina, United States2Dalhousie University, Halifax, Nova Scotia, Canada3Bayer Cropscience, Stilwell, Kansas, United States

The Asian citrus psyllid (Diaphorina citri) is the most significant insect pest to the global citrus industry because it transmits greening disease which leads to tree death. Citrus growers have numerous pesticide options for controlling ACP, how-

ever, many are not bee-safe and must be used before or after bloom, which is not optimal for psyllid control. A new promising candidate for the job is Movento®, a.i. spirotetramat. Movento® is a unique two-way systemic foliar insecticide that is effec-tive on psyllid, and is not believed to be harmful to non-target species such as honey bees. Therefore, it has potential to be a good fit in an IPM program. In collaboration with Bayer CropScience, National Honey Bee Advisory Board, US EPA, Florida Department of Agriculture and Consumer Services and USDA, we investigated the potential effects of Movento® on western honey bee (Apis mellifera) colonies when applied to citrus during bloom using a jointly developed protocol. Colonies were placed at the edge of each of two citrus groves (one control and one treated) at the start of bloom and removed after bloom. Colonies were assessed for strength and health, and residues of spirotetramat and other pesticides. After the conclusion of field work in Florida, colonies were returned to commercial beekeeping operation and transported to northern states for use in pollination of several crops. Follow-up assessments of colonies were performed in May, June, and October. There were no significant differences between control and treatment groups of hives during the in-citrus phase of the study. Both groups of hives experienced high losses of colonies by end of October. Late season colony mortality is attributed to pest and disease factors. Residues of spirotetramat in bee-relevant matrices were low and short-lived. It appears there is a high degree of bee-safety with Movento use during citrus bloom.

T02.016Conservation Biological Control in Organic Citrus Orchards

Gento, A. D.1; Vercher, R.2; Ballester, R.3; González, S.2; Bergés, E.21Estació Experimental Agrària de Carcaixent (IVIA), Carcaixent, Spain2Institut Agroforestal del Mediterrani (UPV)3Grup de Agricultura Ecològica, Unió de Llauradors i Ramaders

Natural enemies are adapted to local environment and to target pests, and their conservation is generally simple and cost-effective. For this reason, conservation of natural enemies is probably the most important and readily available biologi-cal control practice that growers can use. The use of hedgerows and ground cover on orchards can improve the abundance and diversity of natural enemies. In this project, we studied the effect of natural vegetation (Mediterranean hedgerows and ground covers) on the sustainability of beneficial arthropods (Insecta and Arach-nida) associated to organic and conventional citrus orchards. The study was carried out in Valencia (Spain) from 2006 to 2008. Fortnight samplings were carried-out in citrus and hedgerows of four citrus orchards, two organic and two conventional. In order to widen the range of Arthropods studied, insects were collected using portable vacuum device as well as sticky traps. Two kinds of ground covers were sampled, a spontaneous one and another based on sown alfalfa (Medicago sativa L.). The trees sampled included: Ailanthus altissima (Mill.) Swingle.; Citrus reticulata Blanco, Crataegus monogyna Jacq.; Cupressus sempervirens L.; Pistacia lentiscus L.; Pistacia terebinthus L.; Punica granatum L.; Rhamnus alaternus L.; Myrtus communis L. and Arbutus unedo L. The study of the information collected indicated a rela-tion between natural enemies abundance/distribution and plant strata or type of orchard (conventional and organic). Also, the analysis of the population dynamics showed how their distribution changed between plants along the year. The Di-versity Index was also calculated and shown as organic citrus had higher levels of diversity than conventional citrus.

T02.017Morphological and Physiological Characterization of Seven Isolates of Colletotrichum gleosporioides, Responsible of Wither Tip and Tear Stain on Citrus in Morocco

Benyahia, H.1; Bengueddour, M.2; Talha, A.2; Benkirane, R.2; Douira, A.2; Beniken, L.11INRA, Morocco, Bp 257, Kenitra, Morocco2University IBN Tofail, Laboratory of Plant Protection

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In Morocco, citrus tree are constantly subject to various biotic constraints includ-ing viral and fungal diseases. Among the new diseases that have been reported in the Moroccan orchard is the wither tip and tear stain on citrus fruits caused by Colletotrichum gloeosporioides. These diseases have been discovered for the first time in Morocco in 2003 on Citrus trees (Citrus siensis). The objective of this study is a physiological and morphological characterization of seven isolates C. gleopsporioides. The growth of isolate are made on two culture media PDA and CMA. For pathogenicity, inoculations were conducted on fragments of stem and leaves of different varieties of citrus. The results found, it was shown that the type of culture medium plays a very important role in the optimal growth of Col-letotrichum gloeosporioides. In our case the PDA promotes better mycelial growth than the CMA. Evaluation of pathogenicity of isolates on leaves and fragment of citrus varieties has shown that it differs from the isolate, the variety and the explant used. It shows that isolate factors, variety and explant play an important role in disease development.

T02.200Effects of Salinity on Growth Parameters of 9 Citrus Rootstocks

Ramin, A. A.Isfahan University of Technology, College of Agriculture, Department of Horticulture, 8415683111, Isfahan, Islamic Republic of Iran

From long time ago, salinity considered most limiting factors could affect on growth and development of many crops in the word. Generally, citrus fruits are classified as sensitive crops to salinity. As a rule, citrus fruits mostly propagated through grafting, and rootstock of citrus showed different response to soil and water salinity. So in citrus, tolerance to salinity highly depends on rootstock genotype. Therefore a pot experiment under glasshouse conditions was arranged to evaluate response of a citrus rootstocks to salinity. 9 citrus rootstocks name-ly: Sour orange (Citrus aurantium), Bakraii (Citrus reticulata × Citrus limetta), Cleopatra mandarin (Citrus reshni), Rangpur lime (Citrus limonia), Rough lemon (Citrus jambhiri), Macrophylla (Citrus macrophylla), Swingle citrumelo (Poncirus trifoliata × Citrus paradisi), Citrange (Poncirus trifoliata × Citrus sinensis) and Trifoliate orange (Poncirus trifoliata) subjects to 4 levels of salinity (NaCl) of 0 (control), 25, 50 and 75 mM equivalent to 1.4, 4.5, 6.79 and 9.06 dS/m. Treat-ments were applied to six month old seedlings for 60 days. Results indicated that as increasing salinity levels, decrease all growth parameters including leaf number, leaf area, leaf fresh weight, leaf dry weight, stem dry and fresh weight, root fresh and dry weight, root number and root length. Among the genotypes, Cleopatra, Sour orange, and Rangpur lime shows highest tolerance to salinity, respectively. Whereas, Trifoliate orange, Citrange, Citrumelo has no tolerance to salinity and other genotypes (Macrophylla, Rough lemon and Bakraii) showed moderated response.

T02.201Reduction in June Drop, a Way to Reduction of Satsuma Mandarin (Citrus unshiu) Losses

Amiri, N. A.1; Arzani, K.2; Kangarshahi, A. A.11Mazandaran Agricultural and Natural Resources Center, Sari, P.O. Box: 48175-556, Sari, Mazandaran, Islamic Republic of Iran2Agriculture College of Tarbiat Modares University, Tehran, Islamic Republic of Iran

Citrus is one of the most important horticultural crop in Iran that planting land and annual product, placed Iran in the 10 first country of the world. In spite of suitable climate, high crop losses, before and after harvest, cause reduction citrus average yield in Iran. Abscission of flower, fruitlet and fruit, is one reason of these problem. To evaluate the possibility of reducing June drop in Satsuma mandarin, an experiment was conducted in randomized complete block design with 8 treat-ments include: 1. Control; 2. Urea (1%); 3. Urea + 2,4-D (15 mg∙L-1); 4. Urea + GA3 (15 mg·L-1); 5. Urea + Sucrose (1%); 6. Urea + Zinc sulphate (0.5%); 7. Urea + Zinc sulphate + 2,4-D and 8. Urea + Zinc sulphate + GA3 and 4 replications. Treatments was applied before starting June drop in 21 May 2006. After spraying

till ending June drop, number of abscied fruitlets was counted. Then percent of fruitlet abscission was determined in each treatment. Results showed that treat-ments 3, 5 and 8 reduced abscission significantly compare to Control. Treatment 8 reduced abscission and increased yield about 58% and 57% respectively. Also abscission and yield in treatment 8 had significant difference compare to all other treatments. However average fruit weight and diameter in this treatments showed significant reduction compare to Control. Treatments 3 and 5 with about 19.5% abscission reduction, 17% and 13% yield improvement and didn’t have any signifi-cant difference in fruit weight and diameter compare to Control, were two efficient treatments in this experiment.

T02.202Alternate Bearing in Satsuma Mandarin and the Ways of Its Reduction in North of Iran

Amiri, N. A.; Kangarshahi, A. A.Mazandaran Agricultural and Natural Resources Center, Iran, Sari, P.O. Box: 48175-556, Sari, Mazandaran, Islamic Republic of Iran

In the last decade (1999-2008), methods of reducing alternate bearing of citrus in east of Mazandaran was investigated by lengthy research. Most of these meth-ods were decrease fruitlet number in “on year” and increase fruit set and fruitlet number in “off year”. Investigated methods include: 1 - nutritional disorders and their effect on alternate bearing 2 - balance using of chemical fertilizers consider-ing leaf analysis and yield forecast 3 - foliar application of synthetic auxins in “on year” 4 - foliar application of sucrose in “on year” 5 - winter foliar application of urea about two weeks before bud break in “off year” 6 - urea foliar application before and after harvest in “on year”. Results showed that balance chemical fertil-izers reduced alternate bearing index significantly. Auxins and sucrose reduced sink competition in “on year”, so increase fruit size in “on year” and fruit set and yield in “off year”. Winter application of urea, increased fruit set in “off year”. Urea application in harvest time almost disappeared alternate bearing cycle. In fact most treatments adjust alternate bearing cycle by reducing number of “off years” or by increasing average yield of “off years” so decrease difference of “on years” and “off years”. Also most treatments increased fruit average weight and diameter in “on years”.

T02.203Physiological Investigation of Abscission in Thompson Navel Orange (Citrus sinensis)Amiri, N. A.1; Arzani, K.2; Barzegar, M.2; Kangarshahi, A. A.11Mazandaran Agricultural and Natural Resources Center, Sari, P.O. Box: 48175-556, Sari, Mazandaran, Islamic Republic of Iran2Tarbiat Modares University, Agriculture College, Tehran, Islamic Republic of Iran

In some citrus varieties, pre harvest drop is one important reason for high losses in this important horticultural crop of Iran. Recognition of physiology of events in fruit abscission zone and application of some proportional treatments can re-duce or control the abscission. Therefore this experiment was conducted to in-vestigate auxin, cellulase and poly-galacturonase in abscission zone of Thompson navel orange and its relationship with fruit abscission percent. Experiment was performed in randomized complete block design with 7 treatments: 1. Control; 2. 2,4-D; 3 .2,4-D + Urea; 4. 2,4-D + ZnSO4; 5. 2,4-D + Sucrose; 6. 2,4-D + GA3 and 7. GA3 + Urea with four replications. Results showed that Control had the highest abscission percent, the lowest auxin amount and the most enzymes amount. Treatments 2, 3 and 4, reduced abscission compare to Control, sig-nificantly. Auxin amount increased significantly in these treatments. Also poly-galacturonase level in treatments 2 and 3 had significant reduction. Abscission had a significant negative correlation with auxin and a significant positive cor-relation with hydrolytic enzymes. Totalling the results show that treatments 2, 3 and 4, delayed reduction of auxin level, so decreased production or activation of hydrolytic enzymes. Therefore these treatments postponed destroying of cell membrane in abscission zone and caused significant reduction in pre harvest drop compare to control.

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T02.204Fruit Set of Orange Fruits ‘Navelina’ under Different Treatments × Geographical Quadrants

Giacobbo, C. L.; Righi, P. S.; Rossarolla, M. D.; Pagliarini, N. H. F.; Lago, C.Universidade Federal do Pampa, Unipampa, Campus Itaqui, Rua Luiz Joaquim de Sá Britto, s/n. Bairro Promorar, 97650-000, Itaqui, Rio Grande do Sul, Brazil

Generally, in the citrus culture flowering is abundant, however the fruit set is low, rarely passing over 10% of formed flowers. Therefore, this work was done aiming to measure the fruit set of citrus trees cv. Navelina regarding the use of different treatments to increase fruit set in relation to different geographical quadrants. The experiment was carried out in Maçambará/RS at 29º7’57” S, 56º10’38” W and altitude of 95 m. It was used a citrus orchard grafted on trifoliate lemon during two consecutive crops. The orchard was installed in 2004 at 5 × 4 (500 tree/ha) planting spacing. According to classification of Köppen the local climate is Cfa. It was used a completely randomized design with three replications, in a 8 × 4 facto-rial arrangement distributed eight treatments: 1 - Control, 2 - Branch girdling, 3 - Promalin phytoregulator (benzyladenine + gibberellins + AG4 + AG7), 4 - Boron, 5 - Boron + branch girdling, 6 - Boron + Promalin, 7 - Boron + Promalin + branch girdling and 8 - treatment with systemic fungicide (Amistar®); and four geographical quadrants (North, South, East and West). According to the results it was verified interaction among treatments. In general, the treatment 5 showed the best results, except to East quadrant. For the different quadrants, East and South showed the best results regarding different treatments. The use of Boron + girdling improves fruit set of orange tree.

T02.205Mechanical Harvesting and Citrus Tree Stress in Florida

Syvertsen, J. P.; Li, K. T.; Albrigo, L. G.; Melgar, J. C.UF, CREC, 700 Exp Stn Rd, 33850, Lake Alfred, FL, United States

The loss of leaves, branches and flowers along with bark scuffing and root expo-sure that can occur during mechanical harvesting (MH) has not reduced long term yields of healthy trees. Nonetheless, such visible injuries have limited the widespread adoption of mechanical harvesting in Florida’s citrus industry. There was little mea-surable physiological stress from MH in healthy, well-managed trees as leaf water relations, CO2 assimilation and final yield were not affected. The abscission com-pound CMNP, (5-chloro-3-methyl-4-nitro-1H-pyrazole can effectively reduce fruit detachment force and result in fewer visible injuries. Late season MH of ‘Valencia’ sweet orange remains a major problem when young fruitlets for next crop become large enough to be harvested prematurely. We determined if winter drought stress from January to March could delay flowering and fruitlet development so they would be too small to be susceptible mechanical harvesting. Drought stress during winter delayed flowering 2-3 weeks, reduced flowering and vegetative growth but did not reduce new fruit set relative to irrigated trees. Fruit growth after the delayed bloom caught up with the irrigated treatments so final yield and fruit quality were not af-fected. During mechanical harvesting, previously drought stressed trees had a higher fruit removal efficiency and less loss of the smaller young fruit than continuously irrigated trees for up to three months. Thus, winter time drought stress can be an effective practice to delay flowering and to avoid young fruit loss during late season mechanical harvesting of ‘Valencia’ oranges. Fruitlet oleocellosis in late season me-chanical harvested trees did not increase fruitlet drop nor alter internal fruit quality.

T02.206Responses of Four Citrus Rootstocks to Flooding Conditions

Beniken, L.1; Benyahia, H.1; Dahan, R.1; Beqqali, M.1; Benkirane R.21Institut National de la Recherche Agronomique (INRA), Maroc2Université IBN Tofail, Faculté des Sciences et Techniques de Kenitra

The effects of soil flooding on chlorophyll content and vegetative growth were studied in potted six-month –old of four citrus rootstocks plants: Gou-Tou SRA 506 (GT), Moroccan sour orange (Citrus aurantium) (SO), citrange Troyer 72-89 ( Citrus sinensis (L.) Osb. × Poncirus trifoliata (L.) (CT) and citrange Carrizo 61-16-1 (Citrus sinensis (L.) Osb. × Poncirus trifoliata (L.) (CC). Plants were submitted out-doors to four treatments: T0, not flooded (control), and three flooded treatments for 3 (T1), 6 (T2) and 60 (T3) days. For each rootstock, shoot length, number of leaves, and root and shoot dry weights were measured at the end of experiment. Chlorophyll concentration was estimated using a portable SPAD meter. CT and CC rootstocks were the most tolerant to flooding stress. These plants grew more and accumulated more chlorophyll, dray biomass and number of leaves than the others in the several flood stress. These results indicate CT and CC are more ap-propriate rootstocks than GT and SO to resist occasional soil flooding situations.

T02.207Screening of Resistance of Ten Citrus Rootstocks to Water Stress

Beniken, L.1; Benyahia, H.1; Dahan, R.1; Beqqali, M.1; Benkirane, R.2; Benazzouz, A.1; Talha A.11Institut National de la Recherche Agronomique, Bp: 7567, Kenitra, Morocco2Université IBN Tofail, Faculté des Scineces et Techniques de Kenitra, Morocco

Tow month old citrus rootstock seedlings were grown in 0.5 L plastic pots in a greenhouse at El Menzeh (CRRA Kenitra), INRA Morocco, under three moisture regimes (100%, 75% and 50% Hfc) to investigate the effects of water stress on its morphological and physiological characteristics such as plant height, number of leaves per plant, stem diameter, fresh and dry matter accumulation, Relative Water Content (RWC), Transpiration Rat, chlorophyll content, Sucre Soluble and Proline content, respectively. A split plot design with ten citrus rootstocks × three treatments and three replications was used. The measurements were taken at the end of the experiment. Growth parameters (Plant height, Number of leaves per plant, Stem diameter, Fresh and dry matter accumulation), Relative Water Con-tent (RWC), Transpiration rat and Chlorophyll content decreased under water deficit (50% d’Hcc). The deference responses to water stress between the citrus rootstocks are showing. Increase in water stress increased the Sucre Soluble and Proline content, respectively. It is concluded that water stress significantly (p<0.05) affects physiological and morphological characteristics of citrus rootstocks and un-der extreme water deficit (50% d’Hcc) the deference responses are showed between the citrus rootstocks.

T02.208Developmental Trends in Spanish Citriculture Varieties

Caballero, P.1; Garcia-Martinez, M. C.1; Fernández-Zamudio, M. A.1; Alcón, F.2; De-Miguel, M. D.21Instituto Valenciano de Investigaciones Agrarias, Dpto. Economía y Sociología Agrarias, Ctra. Moncada-Náquera, Km 5, 46113, Moncada, Valencia, Spain2Universidad Politécnica de Cartagena, Departamento de Economía de La Empresa, Paseo Alfonso XIII, 48, 30203 Cartagena, Murcia, Spain

This study discusses the varietal composition of citriculture from 1966/67 to 2007/08 and current trends in the introduction and spread of new varieties. Data have been taken from three main sources: the Statistical Annual Records of the Ministry of Agriculture; Records of the number of plants pertaining to different varieties sold by nurseries; and, interviews with marketing companies and agricul-tural co-ops. Concerning trends, we have found that although the Spanish citrus industry encompasses a very wide variety, if one takes into account the number of groups that account for the greatest production, it is focused on three main varietal groups: lemons, Navel oranges and clementines. In early clementines, there is constant demand for the supply of new varieties, which often originate from mu-tations, despite their disadvantages such as small caliber, need for thinning, mul-tiple bud formation and short marketing period. There are new varieties or clones which, although they do not alter the composition of the major groups, represent a qualitative improvement within their group. Thus, the Clemennules group is

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expanded and improved by the Orogrande and Nulessin; the Navel group with N. Powell, N. Rohde, N. Barnfield and the Valencia group with Barberina, Midknight, V. Late Frost and Delta Seedless. There is a very wide variety of early clementines, although only Oronules, Arrufatina and Clemenrubi seem to survive. The main conclusion confirms that there is continual modification to the varietal composi-tion brought about by the producers, who are driven by the income-risk criterion. When a variety becomes commercially obsolete, the producer must substitute it with another more widely accepted one. Markets are witnessing a slow growth in mandarins, while mandarin hybrids have brighter prospects. Late and mid-season navel varieties are well accepted on the market, particularly the home market.

T02.209Growth, Yield and Fruit Quality of ‘Clemenules’ Grown on Six Rootstocks in the Southern Region of Spain during 2008/2009 Season

Hervalejo García, A.1; Martinez Ferri, E.1; Salguero Ortiz, A.2; Arenas Arenas, F. J.21IFAPA Centro Churriana, Cortijo de La Cruz s/n, 29140, Málaga, Spain2IFAPA Centro Las Torres-Tomejil, Spain

The effects of rootstocks on several aspects of orchard profitability (precocity, yield, fruit quality and cost reduction on harvest and pruning), calls for the agronomi-cal study in field of new citrus rootstocks under local edaphic and environmental conditions. This work was carried out to evaluate the effect of six citrus rootstocks on vegetative growth, yield and fruit quality on ‘Clementina de Nules’ trees in a experimental plot in Huelva (Spain). The objective of this study was to com-pare four traditional citrus rootstocks: ‘Citrange Carrizo’ (CA), Citrus macrophylla (MP), ‘Swingle citrumelo’ (CI) and Poncirus trifoliata (PO) to two semi-dwarfing citrus rootstocks: ‘Forner-Alcaide nº5’ (FA5) and ‘Forner-Alcaide nº418’ (FA418). During 2008/2009 season were evaluated vegetative growth (canopy volume), yield efficiency (yield/canopy volume; kg/m3) and fruit quality (fruit weight, juice con-tent (%), soluble solids content (TSS), total acids concentration (TA) and TSS/TA ratio). The results of this work showed that tree size, yield, and fruit quality of ‘Clemenules’ trees were significantly affected by rootstock. ‘Clemenules’ grown on FA418 turned out to be the smallest trees. MP and FA5 induced higher yield per tree than FA418, which recorded the lowest yield per tree. However, no significant difference was found among rootstocks in yield efficiency. MP and PO showed the most attractive fruit color at the moment of the harvest. ‘Clemenules’ trees on FA418 produced heavier fruits than those on CI and FA5. MP induced the lowest fruit quality, in view of juice content (%), density of juice, TSS and TSS/TA ratio, while CI and FA5 showed less flavour quality at the moment of the harvest (watery sweet juice) as a result of an imbalance between TSS and TA.

T02.210Vegetative Growth, Yield and Fruit Quality of ‘Clemenules’ on Six Rootstocks in Andalusia during 2008/2009 Season

Martinez Ferri, E.1; Hervalejo García, A.1; Giménez Moolhuyzen, M.2; Arenas Arenas, F. J.31IFAPA, Centro Churriana, Cortijo de La Cruz s/n, 29140, Málaga, Spain2IFAPA, La Mojonera, Spain3IFAPA, Las Torres-Tomejil, Spain

Continuous generation of news citrus rootstocks makes necessary to study their agronomical response under different edaphic and environmental conditions, in order to improve the yield, fruit quality and citrus orchard profitability. This study was carried out to evaluate the effect of six citrus rootstocks on vegetative growth, yield and fruit quality on ‘Clemenules’ trees in two experimental plots in Andalusia, one of them in Málaga and the other one in Almería (Spain). The objective of this study was to compare three traditional citrus rootstocks: ‘Citrange Carrizo’ (CA), Citrus macrophylla (MP) and ‘Mandarino Cleopatra’ (CL), to three semi-dwarfing citrus rootsocks: ‘Forner-Alcaide nº5’ (FA5), Forner-Alcaide nº13 (FA13) and ‘Forner-Alcaide nº41’ (FA41). During 2008/2009 season were evaluated vegeta-

tive growth (canopy volume), yield efficiency (yield/canopy volume; kg/m3) and fruit quality (fruit weight, juice content (%), soluble solids content (TSS), total acids concentration (TA) and TSS/TA ratio). The results showed significant differ-ence between localities, being Málaga more precocious and more vigorous, but also less productive. Regardless of the locality, FA41 and CA induced smaller canopy volume than MP. MP showed higher yield efficiency than FA41. Significant dif-ferences were found among rootstocks in fruit maturity and juice quality. So FA41 induced higher fruit color that, in the case of Málaga, might have allowed to harvest earlier, together with FA13 and FA5, getting better juice quality than MP, CA and CL at the moment of their harvest. In Almería MP and CL had lower juice content (%) than FA5, FA13 and CA, nevertheless FA5 produced the smallest fruit size. In both localities FA13 can be considered an suitable rootstock for ‘Clemenules’, since it showed the smallest size (cost reduction on pruning and harvest) and high yield together with an adequate content and quality of juice.

T02.211Effect of GA3 and Urea on Yield and Fruit Quantitative and Qualitative Characteristics of Satsuma Mandarin

Malknezhad Matikolaii, R.1; Abdossi, V.1; Akhlaghi Amiri, N.21Islamic Azad University Science and Research Branch, End of Ashrafie Esfahani High Way - Pounak Sq - Hesarak, 1477893855, Tehran, Islamic Republic of Iran2Mazandaran Agricultural and Natural Resources Research Center, Islamic Republic of Iran

Satsuma mandarin (Citrus unshiu) is one of citrus alternate bearing cultivars. Fruit set and yield reduction of Satsuma mandarin in off year, is always an important problem for producers. In this investigation, because of increasing fruit set and yield and also improving fruit quality and quantity characteristics, GA3and Urea were sprayed in different concentrations alone and their combinations on ten years old Satsuma mandarin trees on citrange root stock during late bloom. This experi-ment was done in mahdasht garden of sari city at 2010.The experiment was carried in Randomized Complete Block Design, in 16 May with 4 replication and 6 treat-ments including: control, GA3 (15mg/l), GA3 (15mg/l) + Urea%1, GA3 (30mg/l), GA3(30mg/l) + Urea%1 and Urea%1.The results showed that percentage of fruit set decreased in all treatments, but this reduction was significant in GA3 (15mg/l) treatment. In contrast, GA3 (15mg/l) treatment reduced significantly June drop percentage and increased fruit retention percentage compared with control, wh-erase the lowest amount of fruit retention observed in GA3(30mg/l) + Urea%1 treatment.GA3 and Urea different treatments no effect on increase of yield. Also in GA3(15mg/l) treatment relation of peel weight to peel diameter increased signifi-cantly compared with control, that this can caused improve peel condensation and firmness and also decrease puffiness. Besides because of decreasing peel diameter in all treatments, fruits had thickness peel but firmness.

T02.212Change on Antioxidant Metabolism on Citrus Sunburn-Fruit Induced by High Temperature and Strong Light

Chen, J. J.1; Wan, J. J.1; Li, J. J.21College of Horticulture, South China Agricultural University, College of Horticulture, South China Agricultural University, Guangzhou, 510642, China2Department of Horticulture, Zhongkai University of Agriculture and Engineering, Guangzhou, 510225, China

Potted ‘An Liu’ sweet orange (Citrus sinensis Osbeck cv. An Liu) were used as mate-rials to induced sunburn-fruit incidence through the treatment of high temperature and strong light from high intensity discharge (HID), studying the relationship between fruit-sunburning, air temperature and light radiation. The process of cit-rus fruit-sunburning was divided into four phases: normal fruit, deep yellow spot fruit, little sunburn browning fruit and serious sunburn browning fruit. Sunburn-Fruit in different developing state were picked to study the changes of antioxidant metabolism. The results showed that sunburn-fruit was caused mainly by an inter-action of high air temperature and high light intensity. During initial induction pe-riod, fruit surface temperature > 48 °C was necessary. Symptoms of sunburn-fruit

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were visible during the subsequent incubation period. More higher air temperature at less higher light intensity, 37 °C at 40200 lx, was equivalent to less higher air temperature at more higher light intensity, 33 °C at 46200 lx. And a relatively short induction period at more higher air temperature, 51 minutes at 37 °C, was equiva-lent to more prolonged induction at less higher air temperature, 240 minutes at 33 °C. Superoxide anion (O2-) was significantly accumulated by the stresses of high temperature and high light intensity, the lipoxygenase (LOX) activity significantly increased, the malondialdehyde (MDA) content significantly increased, leading to aggravation of membrane lipid peroxidation. Correspondingly, the activities of su-peroxide dismutase (SOD), peroxidase (POD) and polyphenoloxidase (PPO) were significantly increased while fruit pericarp emerged deep yellow spots. As pericarp became brown, the SOD activity decreased and was lower than that of the normal fruit, the POD activity was still enhanced, the PPO activity decreased, but was higher than that of normal fruit. Ascorbic acid (AsA) and glutathione (GSH) con-tents decreased gradually during sunburn development.

T02.213Effect of Rootstocks on Young Tree Growth and Mineral Nutrients Accumulation in Leaves of Lemon

Xie, Y.Fruit Research Institute, Chongqing Agriculture Science Academy, Jiangjin District Dinshan Road No 167, 402260, Chongqing, China

The major lemon-producing countries have done a lot of research for lemon breed-ing and rootstock improvement. They obtained scion/rootstock combinations adapted both climate and soil of their countries. As a result of strong demand recently, there have being almost 400,000 ha producing lands and 150,000 ton fruit per year in China. The main cultivars in China are Meyer lemon and Eureka lemon, on Poncirus trifoliate or tangerine rootstocks. However, there’s no system-ic comparison of rootstocks in China. In order to obtain optimal lemon scion/rootstock combinations, we grafted Eureka lemon and Fino lemon on Carrizo, Volkamer lemon, Poncirus trifoliate, tangerine, Citrus junos and Citrus grandis re-spectively, and researched the effect of rootstock on vegetation of young trees and accumulation of mineral nutrients in leaves. The study shows significant differ-ence of growth increment and nutrients contents between Eureka lemon and Fino lemon on different rootstocks. Lemon on Citrange is high N, P, K, Ca, Mg and trace elements efficient, with vigorous plant and greatest growth increment. Lemon on Citrus grandis is high N but low P, K and trace elements efficient, with vigorous plant and great growth increment. Lemon on Volkamer and Citrus junos are low N but high P, K and trace elements efficient, with dwarf plant and least growth incre-ment. Lemon on Poncirus trifoliate and tangerine with great N but low P, K and trace elements in leaves does not show draft character. As the result, rootstock can regulate growth type of plant by nutrition absorbing. N contents have significant positive correlation with growth increment, and dwarf plants high correlate the ratio of N and P, K and trace elements respectively.

T02.214Citrus Rootstocks Growth under Salt Stress Conditions

Ramin, A. A.1; Khoshbakht, D.1; Baninasab, B.1; Aghajan zadeh, C.21Isfahan University of Technology, Department of Horticulture, College of Agriculture, 8415683111, Isfahan, Islamic Republic of Iran2Citrus Research Station, Ramsar P.O. Box 46915-335, Iran, Islamic Republic of Iran

Greenhouse study was arranged to assess the salt tolerance of nine citrus root-stocks namely, Sour orange (Citrus aurantium), Bakraii (Citrus reticulata × Cit-rus limetta), Cleopatra mandarin (Citrus reshni), Rangpur lime (Citrus limonia), Rough lemon (Citrus jambhiri), Macrophylla (Citrus macrophylla), Swingle citru-melo (Poncirus trifoliata × Citrus paradisi), Citrange (Poncirus trifoliata × Citrus sinensis) and Trifoliate orange (Poncirus trifoliata). A factorial experiment through complete randomized design (CRD) with three replications and four levels of salt

including 0, 25, 50 and 75 mM NaCl were used. The results showed that un-der salt stress conditions relative chlorophyll content, gas exchange indexes (A), Stomata conductance (gs) and chlorophyll fluorescence yield (Fv/Fm) decreased. Being salty also increased electrolyte leakage. The least electrolyte leakage was seen in “Sour orange”. About the chlorophyll content, “Cleopatra mandarin” and “Sour orange” had the most. Among of genotypes “Sour orange” and “Cleopatra mandarin” had the least decrease in net photosynthetic rate (A). The most Sto-mata conductance (gs) was in the “Sour orange” and “Rangpur lime”. Based on the results it was found out that “Sour orange”, “Cleopatra mandarin”, “Rangpur lime” and “Bakraii” rootstocks were more resistant to changes in the level of salt. But “Trifoliate orange”, “Citrange” and “Swingle citrumelo” were the most sensi-tive ones to salt.

T02.215Quality Improvement in Lemon through Integrated Management of Fruit Cracking

Bal, J. S.; Sandhu, S.Khalsa College, Department of Horticulture, Faculty of Agriculture, 143002, Amritsar, Punjab, India

In the changing global scenario, success of citrus cultivation depends largely on the ideal quality attributes to ensure better marketability. Lemon, a leading acid citrus fruit in northern plains of India, is highly remunerative because of its freedom from citrus canker. Lemon cv. Baramasi bear fruit in many flushes, making it available throughout the year. However, the summer crop is prone to severe fruit cracking which is one of the most exasperating problems. Thus with this focus studies on management of fruit cracking were carried out in Punjab Govt. Orchard, Amritsar for three consecutive years (2007-09) using integrating approach. The investiga-tions were comprised of three sets of experiments during the fruiting year 2007 and 2008. The first experiment comprised of irrigation and mulching practices, second one consisted of graded doses of organic, inorganic and bio-fertilizers whereas in the third experiment folier spray NAA, Potassium Sulphate and Borax were ap-plied. The best treated accrued from three different sets of experiments of 2007 and 2008 were clubbed and tried in 2009. It was revealed that the optimum utilization of different orchard practices viz. proper water management, appropriate fertilizer programme and good preventive spray schedule of growth regulators brought about profound changes in fruit cracking intensity. Hence, the consortium of intelligent management practices like irrigation at 20% ASMD, mulching with black poly-thene, application of FYM (75 kg/tree), inorganic fertilizer (Nitrogen 350g/tree), Azotobacter (18g/tree) and foliar spray of NAA @ 40 ppm in Baramasi Lemon reduced the cracking losses by 94.5%, thereby resulting in impressive impact on fruit quality.

T02.216Analysis of Genetic Diversity of Acid Lime (Citrus aurantifolia) in Oman Using AFLP Fingerprinting

Al-Yahyai, R. A.; Al-Sadi, A. M.; Al-Said, F. A.; Al-Saadi, N. A.; Al-Moqbali, H. S.Sultan Qaboos University, Department of Crop Sciences, CAMS, P.O. Box 34, Al-khod 123, Muscat, Oman

A study was conducted to evaluate genetic diversity of acid lime (Citrus auranti-folia) in Oman using AFLP Fingerprinting. Over 150 lime samples were collected from 12 different districts in the country. Following DNA extraction, amplified fragment length polymorphism (AFLP) analysis was conducted on eight randomly selected lime samples using 18 different primer-pair combinations. The six primer-pair combinations which gave the highest number of bands and polymorphism were selected for further analysis. Most primer-pair combinations produced be-tween 100 and 180 bands, some of them having 100% polymorphism. AFLP anal-ysis showed over 90% genetic similarity among most of the lime samples. Analysis also showed a relatively high rate of gene flow between farms and geographically separated regions, implying frequent exchange of genetic materials within and among geographically separated areas. The results are discussed in terms of influ-ence of farmers’ practices on diversity of lime germplasm in Oman.

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T02.217Sensorial Analysis and Fruit Quality in Citrus sinensis (L.) Osbeck from Northern Italy (Piedmont)

Canterino, S.; Donno, D.; Mellano, M. G.Dipartimento di Colture Arboree, Facoltà di Agraria, Università degli Studi di Torino, Via Leonardo da Vinci 44, 10095, Grugliasco, Turin, Italy

The loss of genetic variability of fruit is a worldwide problem and the genetic ero-sion is recurrent. The identification, characterisation and valorisation of traditional genetic resources are becoming fundamental to avoid the loss of this precious germ-plasm. The citrus grown in particular environments represent an important genetic resource with traits (e.g. frost and diseases resistance) useful in breeding programs or for direct exploitation. The aim of the research was to assess the nutritional properties and consumer acceptability of some local Citrus sinensis (L.) Osbeck accessions from Northern Italy (Maggiore Lake, Verbano area). Physical (weight, size, juice percent-age, peel thickness) and chemical (pH, titratable acidity TA, total soluble solids TSS and vitamin C content) parameters were studied on 15 accessions (3 Pigmented, 4 Navel and 8 Common oranges). On six of these accessions, chosen for their good morpho-biological characteristics, samples of fruit were analysed by a trained panel to evaluate their sensorial quality. The sensorial attributes studied were: odour dur-ing peeling, hardness, juiciness, flavour, aroma, astringency and overall judgment. Significant differences were found among the groups for TA, TSS/TA and vitamin C content ranging from 36.89 to 67.67 mg/100 mL. Positive correlations between TA and sourness, aroma intensity and the overall judgment, astringency and bitterness were evidenced. Even if these accessions occupy the northern distribution range of the citrus in Italy oranges have good quality and good sensorial traits. These results were important to define the traits of the local germplasm and support the develop-ment of economic activities (trade, rural tourism, nursery, and educational activities).

T02.218Citrus Peel Structure and Its Relation to Pitting Fruit Rate

Li, J.1; Chen, J.21College of Horticulture and Landscape Architecture, Zhongkai University of Agriculture and Engineering, 510225, Guangzhou, China2College of Horticulture, South China Agricultural University, 510642 Guangzhou, China

Citrus pitting or cracking occurred in almost all of citrus orchards during fruit ripening and resulted in serious economic loss, especially in orchards having more valuable citrus varieties such as ‘Hong Jiang’ (grafting chimaera; of which flesh is mostly from Citrus reticulata Blanco and peel is from Citrus sinensis Osbeck) sweet orange, navel orange, Shatangju (Citrus reticulata Blanco cv. Shatangju) and so on. Obvious differences existed in flavedo, albedo and cell wall ultrastructure between healthy and pitting citrus peel among different pitting-fruit-rate cultivars. The cul-tivars of low pitting fruit rate had intact-structural flavedo, albedo, middle lamella (ML) and primary wall (PW), while the peel of high pitting fruit rate cultivars was disrupted with decomposed flavedo, albedo, middle lamella, primary wall and poor spongy layer network. In addition, there was few starch granules in the area of nearly cell wall of Navelina navel orange, Hongjiang sweet orange and Shatangju.

T02.219Plant Growth and Fruit Yield of ‘Valencia’ Sweet Orange Grafted on Thirteen Rootstocks

Mourão Filho, F. A. A.1; Stuchi, E. S.2; Mendes, B. M. J.3; Cantuarias-Avilés, T.1; Silva, S. R.11Universidade de São Paulo, Escola Superior de Agricultura ‘Luiz de Queiroz’, Av. Pádua Dias, 11, Departamento de Produção Vegetal, 13418-900, Piracicaba, SP, Brazil2Embrapa Mandioca e Fruticultura Tropical, Estação Experimental de Citricultura de Bebedouro, Rodovia Brigadeiro Faria Lima, Km 384, 14700-971, Bebedouro, SP, Brazil3Universidade de São Paulo, Centro de Energia Nuclear na Agricultura, 13400-970, Piracicaba, SP, Brazil

Vegetative growth and fruit yield of ‘Valencia’ sweet orange were evaluated on plants grafted on the rootstocks ‘Swingle’ citrumelo, ‘Rangpur’ lime, Poncirus trifoliata, ‘Volkamer’ lemon, ‘Cleopatra’ mandarin, ‘Sunki’ mandarin, ‘Caipira’ sweet orange, as well as on the somatic hybrid rootstocks ‘Caipira’ sweet orange + ‘Cleopatra’

mandarin, ‘Caipira’ sweet orange + ‘Rangpur’ lime, ‘Caipira’ sweet orange + ‘Volka-mer’ lemon, ‘Ruby Blood’ sweet orange + ‘Volkamer’ lemon, ‘Cleopatra’ mandarin + ‘Volkamer’ lemon, and ‘Rangpur’ lime + ‘Sunki’ mandarin. The experiment was installed in 2002 in the Southern region of Brazil, São Paulo State, with a Köeppen’s Cwa climate. A completely randomized block design was utilized, with five replica-tions and three plants per plot. Plant growth and yield data were collected from 2006 through 2009 (year 4 to 7 after planting). Larger tree sizes were recorded on ‘Volkamer’ lemon and ‘Cleopatra’ mandarin. In general, the somatic hybrid root-stocks induced smaller tree size and smaller cumulative yield to ‘Valencia’ sweet or-ange trees. Among these rootstocks, ‘Caipira’ sweet orange + ‘Cleopatra’ mandarin, ‘Caipira’ sweet orange + ‘Rangpur’ lime, and ‘Caipira’ sweet orange + ‘Volkamer’ lemon conferred higher yield efficiency to ‘Valencia’ sweet oranges. ‘Swingle’ citru-melo, ‘Rangpur’ lime, and ‘Volkamer’ lemon induced highest cumulative yields, good yield efficiency, and large tree size. ‘Cleopatra’ and ‘Sunki’ mandarins induced low yield efficiencies in ‘Valencia’ sweet orange trees.

T02.220Growth and Physiological Characterisation of in vitro Rooted Citrus macrophylla Explants as Affected by NaCl Stress and Different Concentrations of NO3

-, K+ and Ca2+

Perez-Tornero, O.; Tallon, C. I.; Andujar, S.; Cordoba, F.; Navarro, J. M.Departamento de Citricultura, IMIDA, C/ Mayor s/n, 30.150, La Alberca, Murcia, Spain

Complexity in the mineral nutrition of plants considerably increases with saline ions in the medium since salinity produces a nutritional imbalance in the plant. Additionally, saline ions interact with essential nutrients such as NO3-, K+ and Ca2+. In this study we analyzed the behaviour of in vitro rooted Citrus macrophylla ex-plants, in a control medium, in saline conditions (0 and 150 mM NaCl) and with three levels of NO3

-, K+ and Ca2+ (Low, Control and High - 50%, 100% and 150% of the concentration in the DKW medium). The salinity decreased the length of roots and shoots but it had no effect on the number of roots. In the non-saline media, damaged or fallen leaves were not observed. The Low level of Ca2+, in the saline medium, decreased the length of roots and shoots and produced the highest number of damaged leaves. In the non-saline medium the Ca2+ level had no effect on the growth parameters. The level of K+ only affected the length of shoots in the saline medium; the longest shoots were obtained with the High level. The lowest number of damaged leaves was observed with the Low K+ level. The Low NO3

- level produced the longest shoots in the non-saline media and the longest roots in the saline media. This NO3

- level produced the lowest number of damaged leaves.

T02.221Classic Methods and Biotechnical Tools in Lemon Breeding: Preliminary Results

Perez-Tornero, O.; Cordoba, F.; Moreno, M.; Yuste, L.; Porras, I.Departamento de Citricultura, IMIDA, C/Mayor s/n, 30.150, La Alberca, Murcia, Spain

Spain is the most important lemon-producing country of the Mediterranean basin. The aim of lemon improvement is the selection of lemon trees giving excellent quality and productivity and the production of seedless lemons having the fea-tures demanded by consumers. In the spring of 2008 and 2009 we carried out 600 crossings between different lemon cultivars. We obtained about 34% fructification. Four months after pollination the fruit harvest and the immature embryos rescue were carried out. About 280 plants were cultivated. The plants of 2008 were anal-ysed by flow cytometry and ten triploid and one tetraploid plant were selected. The plants of polyembryonic seeds will be analysed by molecular markers to select zy-gotic plants. Also, we have made several sowings of seeds and about 1800 seedlings of different lemon cultivars were analysed by flow cytometry: 24 triploid and 10 tetraploid plants were selected. The triploid and tetraploid plants will be cultivated in the field for their evaluation and the tetraploid plants selected could be used to obtained triploid plants through crossing with diploid plants.

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T02.222Plant Growth, Yield and Citrus Variegated Chlorosis Incidence on Mediterranean Mid-Season Sweet Oranges (Citrus sinensis L. Osbeck)

Silva, S. R.1; Stuchi, E. S.2; Cantuarias-Avilés, T.1; Girardi, E. A.1; Reiff, E. T.21Universidade de São Paulo, Escola Superior de Agricultura ‘Luiz de Queiroz’, Departamento de Produção Vegetal, Avenida Pádua Dias, 11, P.O. Box 9, 13418-900, Piracicaba, SP, Brazil2Embrapa Mandioca e Fruticultura Tropical, Estação Experimental de Citricultura de Bebedouro Rodovia Brigadeiro Faria Lima, Km 384, 14700-971, Bebedouro, SP, Brazil

Mid-season sweet oranges ‘Sanguínea’, ‘Amares’, ‘Prata da Ponte’, ‘Prata Lima’, ‘Pala’, ‘Portela’, ‘Évora’, ‘Vale dos Besteiros/161’, ‘Biondo’, ‘Belladona’, ‘Vera’, ‘En-trefina’, ‘Pardilhó’, ‘Verde de Espanha’, ‘Vale dos Besteiros/175’, ‘RAH’ and ‘Maçã’ budded onto ‘Sunki’ mandarin were planted in 2001, in Bebedouro, SP, Brazil. A randomized block design, with 3 replications and 2 plants per plot was utilized. In the 2006-2008 period (year 5 to 7 after planting), mean values of plant height, plant diameter and canopy volume were 3.51 m, 3.11 m and 18.82 m3, respec-tively, while the mean increment of canopy volume was 3.83 m3·yr-1. Despite of its large vegetative vigour, the ‘Belladona’ variety showed a low cumulative yield in the 2005-2008 period of 28.98 kg/plant (12.55 t·ha-1). In the same period, the other varieties had similar mean yields, of 119.54 kg/plant (51.75 t·ha-1). In the first two commercial harvests (2005 and 2006), the ‘Biondo’ and ‘Portela’ variet-ies produced less than 5% of total cumulative yield, against an average of 23.23% in the other varieties. Yield efficiency of ‘Prata Lima’ (3.12 kg·m-3) and ‘Verde de Espanha’ (3.37 kg·m-3) significantly differed from that of ‘Belladona’ (0.59 kg·m-3), while the other varieties had a mean yield efficiency of 2.37 kg·m-3. The alternate bearing index was similar for all the varieties (0.82), indicating a pronounced yield alternation under dry conditions. In the 2005-2008 period, the citrus variegated chlorosis (CVC) affected all the varieties, with a lower incidence (< 33%) in the ‘Belladona’ and ‘Pardilhó’ scions. These two varieties also had lower CVC severity score (<0.33), while ‘Evora’, ‘Vale dos Besteiros/161’, ‘Entrefina’, ‘Vera’ and ‘Verde de Espanha’ sweet oranges had the highest CVC incidence (> 80%) and more se-vere disease symptoms.

T02.223Plant Growth, Yield and Fruit Quality of Ten Satsuma Mandarin Varieties (Citrus unshiu Marcow.)

Silva, S. R.1; Stuchi, E. S.2; Cantuarias-Avilés, T.1; Girardi, E. A.1; Reiff, E. T.21Universidade de São Paulo, Escola Superior de Agricultura ‘Luiz de Queiroz’, Departamento de Produção Vegetal, Avenida Pádua Dias, 11, P.O. Box 9, 13418-900, Piracicaba, SP, Brazil2Embrapa Mandioca e Fruticultura Tropical, Estação Experimental de Citricultura de Bebedouro Rodovia Brigadeiro Faria Lima, Km 384, 14700-971, Bebedouro, SP, Brazil

Satsuma mandarins ‘Clauselina’, ‘Okitsu’, ‘Unshiu’ SRA 529, ‘Saigon’ SRA 227, ‘Panaché’ SRA 579, ‘Salzara’ SRA 341, ‘Miyagawa’ SRA 444, ‘Kowano’ SRA 167, ‘FCAV-59’ and ‘A2 60.0’ grafted onto ‘Swingle’ citrumelo, were planted in 2001 using a randomized block design, with 3 replications and 2 plants per plot, in Bebedouro, at the northern region of São Paulo State, Brazil. The experimental plots were drip irrigated from 2006. In the 2004-2008 period, the ‘Okitsu’, ‘Un-shiu’, ‘Miyagawa’, ‘Kowano’ and ‘A2 60.0’ varieties had a cumulative yield of 132.20 to 206.11 kg/plant (86.20 to 134.12 t·ha-1). In the same period, the cumulative yields of ‘Clauselina’, ‘Saigon’, ‘Panaché’, ‘Salzara’ and ‘FCAV-59’ were significantly lower, from 17.54 to 99.76 kg/plant (11.70 to 66.37 t·ha-1). In the 2006-2008 period (year 5 to 7 after planting), mean yield efficiency was 3.70 kg∙m-3 for all but the ‘Panaché’ mandarin, which had the lowest yield efficiency, of only 0.48 kg·m-3. ‘Miyagawa’ and ‘A2 60.0’ mandarins had lowest alternate bearing index (0.38 and 0.40, respectively), while the other varieties showed indexes from 0.55 to 0.70. In 2008, higher canopy volume growth rate was recorded on ‘Unshiu’ Satsuma trees (11.90 m3·yr-1), while the lowest growth rate was observed on ‘Clauselina’ trees (3.26 m3·yr-1). In the 2006-2008 period, the ‘Panaché’ and ‘Unshiu’ mandarins had

the lowest ratio, of 10.68 and 11.41 respectively, indicating their earlier ripening behavior. On the other hand, the ‘Clauselina’, ‘Okitsu’, ‘Miyagawa’ and ‘A2 60.0’ mandarins showed the highest ratio values, from 14.04 to 15.07, and behaved as late-ripening varieties. An intermediate group, of mid-season ripening varieties, was formed by the ‘Saigon’, ‘Salzara’, ‘Kowano’ and ‘FCAV-59’ mandarins, with ratio values of 12.34 a 13.07.

T02.224Effects of Different Pruning Intensity Applications on Plant Shape and Yield Quality of ‘SRA 63’ Clementine

Zurru, R.1; Deidda, B.1; Mulas, M.21AGRIS - Sardegna, Department of Wood and Fruit Tree, Cagliari, Italy2Department of Economics and Tree Systems of The University of Sassari, Via de Nicola 9, I-07100 Sassari, Italy

Pruning of Clementine requires a lot of time: more than 50 days of work per hect-are in the traditional forms of orchard management. Because of the high cost and the lack of specialised workers, we observe a general tendency to delay the fre-quency of pruning in the citrus orchards. On the other hand regular pruning is of fundamental importance to have good fruit quality, to maintain health status of the orchard, and to store their regular productivity. In order to optimise the Clem-entine pruning technique, reduce the time of execution and maintain a good level of yield of better quality a field experiment was designed. In 1996 a commercial orchard of ‘SRA 63’ Clementine located in Southern East Sardinia was selected for the experiment. Plants were grafted on ‘Troyer’ Citrange, twenty-year-old, spaced 7 × 5 m, shaped to globe, over 4 m in height, and showed an excessive number of main branches (about 7-8 per tree) with a dense canopy. All the orchard was preliminarily submitted to a gradual shape pruning during the first four years. In 2000 two main plots of 72 plants each were designed: A) pruning every year; and B) pruning every two years. The orchard was observed for a further period of four years for the following characters: trunk section area; canopy size, working time for pruning; pruned wood weight; fruit yield; fruit size. In both pruning applications (A and B) the canopy was more open and green than in the past, with a improve-ment of the plant heath status, a reduction of the number of treatments, water for irrigation and fertilizers, less working time for harvest, and with a significant better fruit size and increase of the production value.

T02.225Production and Citrus Variegated Chlorosis (CVC) Tolerance of Portuguese Midseason Sweet Orange Selections (Citrus sinensis (L.) Osbeck)

Stuchi, E. S.1; Silva, S. R.2; Cantuarias-Avilés, T. E.2; Girardi, E. A.1; Reiff, E. T.11Embrapa Mandioca e Fruticultura Tropical, Estação Experimental de Citricultura de Bebedouro, Rodovia Brigadeiro Faria Lima, Km 384 ,14700-971, Bebedouro, São Paulo, Brazil2Universidade de São Paulo, Escola Superior de Agricultura ‘Luiz de Queiroz’, Departamento de Produção Vegetal, Avenida Pádua Dias, 11, P.O. Box 9, 13418-900, Piracicaba, SP, Brazil

Production and CVC tolerance of 14 Portuguese midseason sweet orange selections (‘Tua 145’, ‘Tua Graúda’, ‘Tua Ponte’, ‘Tua Sr. Mamede’, ‘Tua 149’, ‘Tua 160’, ‘Tua 176’, ‘Convento’, ‘Grada’, ‘Jaffa’, ‘Ovale’, ‘Setúbal 174’, ‘Setúbal 180’ and ‘Pera de Vidigueira Sr. Antunes’) were evaluated in the period 2005-2008. Trees were bud-ded onto Sunki mandarin and planted in 2001 at 7 × 5 m in Bebedouro, SP, Brazil. Experimental design was randomized blocks, with three replications and two trees in the unit. Data was submitted to ANOVA with means compared by the Scott-Knott Test (P < 0.05). ‘Tua 145’, ‘Tua Ponte’, ‘Jaffa’ and ‘Ovale’ were included in a low-production selections group (61.0-78.7 kg/tree or 17.4-22.5 t·ha-1). All other selections yielded 130.2 to 170.0 kg/tree or 37.2 to 48.5 t·ha-1 in 2005-2008. Production in the first two harvests ranged from 22% to 33% of the total yield. ‘Setúbal 174’ showed a more pronounced alternate bearing index (0.74) than ‘Tua 145’ (0.46). In all years, fruits were harvested in September, confirming the midsea-son maturing behavior. Juice content varied from 40 to 51%, and ‘Tua Ponte’ was not indicated as a suitable selection for juice extraction because of its low yield and

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juiciness. The Portuguese sweet orange selections were grouped in three classes of ratio: > 19 (‘Jaffa’); 15-18 (‘Ovale’ and ‘Tua Graúda’) and < 14 (all other varieties). Fruit ripening was directly influenced by the juice acid concentrations. Highest to-tal soluble solids (2.33-2.46 kg/box) were accumulated by ‘Tua Ponte’, ‘Convento’ and ‘Setúbal 180’. CVC did not affect ‘Jaffa’ sweet orange until 2008 and this may be a tolerant variety. Symptomatic plants were observed in all other selections, prominently in ‘Tua Sr. Mamede’, ‘Grada’ and ‘Pera Vidigueira Sr. Antunes’ (mean of 56.6% and 0.81 for CVC incidence and severity score, respectively).

T02.226‘Garbí’ and ‘Safor’ Mandarins, Two New Late Maturing Mandarin Triploid Hybrids Obtained by Embryo Rescue and Flow Cytometry

Navarro, L.; Aleza, P.; Cuenca, J.; Juárez, J.; Pina, J. A.Centro de Protección Vegetal y Biotecnología, Instituto Valenciano de Investigaciones Agrarias, Ctra. Moncada a Náquera, Km. 5, 46113, Moncada, Valencia, Spain

Citrus is the most extensively produced fruit tree crop in the world. There are two clearly differentiated markets: fresh fruit and processed juice. In the Mediterranean area, citrus fruits are primarily produced for the fresh fruit market and Spain is the principal producer. Seedlessness is one of the most important characteristics for mandarins on for fresh consumption, since consumers do not accept seedy fruits. Parthenocarpy is an essential trait for seedless fruit production, and this character-istic is present in citrus germplasm. Triploid plants have very low fertility, are gener-ally sterile and do not induce seeds in other cultivars by cross pollination. Citrus triploid plants can be obtained by 2x × 2x hybridisations exploiting natural events of polyploidization such as 2n gametes, using embryo rescue and flow cytometry to select triploid plants. A triploid breeding program has been carried out in Spain since 1995 with the objective to produce new high quality late-season and seedless triploid mandarin hybrids. In this work, we describe ‘Garbí’ and ‘Safor’ mandarins developed within this program, characterized by its high quality, late-season ripen-ing and seedless fruits. Protection of Plant Breeder´s Rights of these cultivars has been requested in the European Union, Morocco, Egypt, South Africa and Turkey and also a U.S. Plant Patent has been requested. Pathogen-free plants have been obtained by shoot-tip grafting in vitro and healthy budwood was released in 2008 to twenty-two Spanish nurseries that are already producing certified plants for the growers.

T02.227Horticultural Performance of ‘Tahiti’ Lime onto Twelve Rootstocks in Northern São Paulo State, Brazil

Cantuarias-Avilés, T.1; Stuchi, E. S.2; Mourão Filho, F. A. A.1; Silva, S. R.11Universidade de São Paulo, Departamento de Produção Vegetal, Escola Superior de Agricultura ‘Luiz de Queiroz’, Av. Pádua Dias 11, P.O. Box 9, 13418-900, Piracicaba, SP, Brazil2Embrapa Mandioca e Fruticultura Tropical, Estação Experimental de Bebedouro, 14700, Bebedouro, SP, Brazil

‘Tahiti’ lime canopy volume, drought tolerance, yield and fruit export quality were evaluated in Bebedouro, Northern São Paulo State, onto twelve rootstocks: the hy-brids ‘Changsha’ mandarin × Poncirus trifoliata ‘English Small’ and Rangpur lime × ‘Swingle’ citrumelo; the trifoliates ‘Rubidoux’, ‘FCAV’ and ‘Flying Dragon’; the mandarins ‘Sun Chu Sha Kat’ and ‘Sunki’; the Rangpur limes ‘Cravo Limeira’ and ‘Cravo FCAV’; ‘Carrizo’ citrange, ‘Swingle’ citrumelo and ‘Orlando’ tangelo. The plots were planted in 2001 without supplementary irrigation, at 8 × 5 m spacing, using a randomized block design. After 7 years from planting, the ‘Flying Dragon’ trifoliate conferred smallest canopy volume and lowest cumulative yield, while the ‘Orlando’ tangelo induced largest canopy volume, but low cumulative yield. Largest cumulative yields were recorded onto ‘Cravo FCAV’ and ‘Cravo Limeira’ Rangpur limes. In the 2006-2008 period, yield efficiency was significantly higher onto ‘Flying Dragon’. Reduced tree size and high yield efficiency conferred by this rootstock allow its recommendation for high-density plantings. Nevertheless, its low drought tolerance limits its use to irrigated conditions. On the other hand, both Rangpur lime scions and the ‘Sunki’ mandarin induced high tree tolerance

to drought. Based on the overall tree performance, a hierarchical cluster analysis identified two groups of rootstocks with similar effects on ‘Tahiti’ lime: (i) both Rangpur limes and (ii) the ‘Changsha’ × ‘English Small’ hybrid and ‘FCAV’ trifoli-ate. The ‘Flying Dragon’ rootstock had a unique effect over ‘Tahiti’ limes, different from all the other rootstocks, inducing higher yield efficiency, earlier bearing, larger percentage of fruit harvested in the second semester in the internal market, and a larger production of export fruits with larger size, adequate peel color and high soluble solid content.

T02.228Evaluation of Graduate A+ for Control of Post-Harvest Decay in Lemons

Wright, G. C.University of Arizona, Yuma Agriculture Center, 6425 W. 8th Street, 85364, Yuma, AZ, United States

We evaluated Graduate A+ (a mixture of Fludioxonil and Azoxystrobin) as well as a Pyrimethanil-Imazalil mix for control of Penicillium spp. We selected lemons with no apparent injuries from a local packinghouse. Treatments were untreated control, Graduate A+ at 150, 300, 600, and 1200 ppm, and the mix of Pyrimethanil (Pem-botec) 350 ppm + Imazalil 350 ppm. All fungicides were applied as a drench, then three days later, a Penicillium ‘slurry’ was applied through a spray bottle ‘to drip’. Fruit were analyzed on at 7, 14, 21, 32 and 39 days after treatment. Before day 21, the fungicides had no significant effect upon disease incidence; however, after day 21, all fungicides had significantly less infested fruit as compared to the untreated control. All fungicides were able to limit the spread of the disease from infested to non-infested fruit. There was no significant effect of the fungicides upon the num-bers of infested fruit until after day 32. By day 39, the Pembotec + Imazalil treat-ment and the Graduate A+ at 1200 ppm led to slightly less infested fruit than did the other treatments. Expansion of the lesions was generally significantly less with the Graduate A+ products as compared to the untreated control, or the Pembotec + Imazalil treatment. For the few fruit that had disease, the Graduate A+ treatments kept the spread of the disease across the peel and the sporulation in check. How-ever, for the few fruit that had the disease, the Pembotec + Imazalil treatments did not stop the spread of the disease across the peel, nor did it stop the sporulation.

T02.229Characterization of Self-Incompatibility Reaction of Some Clementine (Citrus clementina Hort. ex Tan.) Genotypes by Histological Analysis

Aka Kacar, Y.1; Aslan, F.2; Eti, S.1; Boncuk, M.2; Yildirim, B.1; Yalcin Mendi, Y.1; Yesiloglu, T.1; Distefano, G.3; La Malfa, S.31Cukurova University, Agriculture Faculty, Horticulture Department, 01330, Adana, Turkey2Cukurova University, Institute of Basic and Applied Science, Biotechnology Department 01330 Adana, Turkey3Catania University, Horticulture Department Catania, Italy

Seedlessness is one of the most important characteristic for fresh consumption, so fruits with seed may lead to a decrease of the fruits value. Several cultivars, char-acterized for high compatibility level with other varieties, often produce a several seeds in fruit (Soler et al.; 1999). Although seeds in mandarins-like represent a huge problem for citrus industry, the mechanisms related to citrus incompatibility have not been deeply investigated. In this study, pollen tube growth of forty Clementine mandarin genotypes from Citrus Genetic Collection Field of Agricultural Faculty of Cukurova University (Turkey) was investigated by histological assay in self pol-lination conditions. To characterize the self-incompatibility reaction, flowers were self pollinated. Five flowers from each self-pollinated genotype were collected se-quentially (3, 5, 7, 9, 11, 13, 15, 20th days after pollination). All samples fixed in FPA70 solution and stored at 4 °C. Pistil samples were stained with aniline blue for microscope observation. The preparations were observed by fluorescence mi-croscope after staining and squashing. The ratio of the length of the longest pollen tube to the style length was recorded as a percentage. Pollen tubes of thirty-nine of the genotypes arrested in the upper or middle part of style and none reached the

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base of the style. Only ‘SRA86’ coming from pollen tubes grew down the style and reached the ovary at fifteenth day. In the second year of the study the compatible genotype (SRA86) will be compared with self incompatible genotypes in order to investigate compatibility/incompatibility mechanism by molecular methods.

T02.230A New Line of Valencia: ‘Changshou No.1’

Changfeng, C.1; Jurong, Q.1; Chunqing, W.1; Zhaoxin, W.1; Lin, H.1; Dequan,Y.21Fruit Research Institute, Chongqing Academy of Agriculture Sciences, Jiangjin Chongqing, 402200, China2Agriculture Bureau of Changshou, Chongqing, China

The new line of valencia ‘changshou No.1’ (Citrus sinensis L.), with larger fruit and less seeds, selected from grafted-valencia in Changshou, Chongqing. The ovoid spring leaf of the new line is averaged 8.86 cm long and 4.68 wide, significantly larger than that of valencia, which is averaged 8.32 cm long and 3.70 cm wide. The major axis and minor axis of stomata in the new line is 8.95 μm and 7.41 μm, smaller than that of valencia 10.71 μm and 8.35 μm, and there are 6.6 and 4.0 chloroplasts in the stomata of the new line and Valencia, respectively. DNA polymorphism of the new line (C. sinensis cv.) and valencia were determined by inter simple sequence repeat (ISSR) molecular markers. The results also showed that there were genetic diversity with 3 primer pairs in genomic DNA between the new line and valencia. The new line has excellent characteristics such as: (1) Larger fruit. The fruit averaged 210 g is larger than valencia fruit averaged 160 g. (2) Less seeds. The average seed number is less than 1.0 per fruit, significantly less than that of valencia. (3) High quality. The total soluble solid content is 10.6 %. There are 9.4 g total sugar and 0.94 g acid contents per 100 ml juice. The total soluble solids to acidity ratio is 11.3. (4) Early maturing. It matures in the last ten days of March or the first ten days of April, 15 days earlier than valencia.

T02.231Research on the Effects of Foliar Urea Applications on Fruit Quality in ‘Washington Navel’ Oranges

Dal, B.1; Gubbuk, H.21Batı Akdeniz Agricultural Research Institute Antalya Turkey, Pk: 35, No:25, 07100, Antalya, Turkey2Akdeniz University Agricultural Faculty, Department of Horticulture Antalya Turkey

This research was conducted in 2005 on the ‘Washington Navel’ orange lot situated in the central premises of Batı Akdeniz Agricultural Research Institute in Anta-lya. Seventy healthy ‘Washington Navel’ trees on sour orange rootstock, planted in 1956 with a distance pattern of 8 × 7 m were used. Plant nutrient element analysis and carbohydrate analysis were conducted in Batı Akdeniz Agricultural Research Institute Çallı Central Laboratory and pomology analysis in the Pomology Labora-tory in the Kayaburnu premises of Batı Akdeniz Agricultural Research Institute. Low bi-uret urea application on ‘Washington Navel’ orange trees at six applica-tion times and a nontreated control was investigated for effects on fruit quality and pomological characteristics. Low bi-uret urea (1.75%) was applied at 0.16 kg pure N per tree with 10 trees per treatment. Pomology analyses were conducted on the fruit samples. Some pomology criteria such as titratable acid amount, fruit juice amount, total soluble solid amount, total soluble solids/titratable acidity ratio, change in rind thickness have been examined.

T02.232Evaluation of Citrus Rootstocks for Lemons and Valencia’s in the Eastern Cape Citrus Production Region of South Africa

Sippel, A. D.1; Bijzet, Z.1; Combrink, N. K.2; Maritz, J. G. J.21Agricultural Research Council, Institute for Tropical and Subtropical Crops, Private Bag X11208, 1200, Nelspruit, South Africa2Agricultural Research Council, Institute for Tropical and Subtropical Crops, Addo Research Station, P.O. Box 25, 6105, Addo, South Africa

The Eastern Cape is one of the most important citrus production areas in South Africa with roughly 34% of the total citrus plantings. In order to stay competitive old citrus orchards have to be replaced regularly as new cultivars become avail-able. The citrus rootstocks that are currently used commercially show very poor performance in replant soils. This problem necessitated a research project to find rootstocks that will perform in replant soils. Subsequently two trials have been established during 1997 and 1998, the main objective thereof being to evaluate newly bred Agricultural Research Council - Institute for Tropical and Subtropical Crops’ (ARC-ITSC) hybrid rootstocks, imported rootstocks and commercially used rootstocks against each other in replant soils. Preliminary results indicate that a number of newly-bred hybrid rootstocks and imported rootstocks outper-form the commercial rootstocks.

T02.233Fruit Yield and Quality Assessment of Citrus Grown under Arid-Subtropical Conditions of Oman

Al-Yahyai, R. A.1; Al-Said, F. A.1; Khan, I. A.2; Al-Kalbani, Z. H.1; Al-Mamari, Y.1; Al-Kharusi, L. M.11Sultan Qaboos University, Department of Crop Sciences, CAMS, P.O. Box 34, Al-Khod 123, Muscat, Oman2University of Agriculture, Faisalabad, Pakistan

Fruit yield and quality of several citrus species grown in the subtropical arid region of northern Oman were evaluated. The purpose of this evaluation was to determine the physical and chemical quality of native and exotic citrus species and clones introduced to Oman for the purpose of commercial production such as orange, grapefruit, calamondin, acid lime and sweet lime. Furthermore, this evaluation included several species for use as rootstocks such as rangpur lime, macrophylla, palestine sweet lime, rough lemon, and volkameriana. Fruit yield, fruit dimensions, TA, pH, TSS, fresh and dry weight, fruit color, and fruit size were determined for all species and clones studied. The results indicated significant variations in the parameters measured; nevertheless, initial assessment indicated the suitability of all tested citrus for commercial production and as rootstocks under the arid-subtropical climate of Oman.

T02.234A Rapid Molecular Method for Detection of Spoilage Yeasts in Orange Juice

Guo, D. Q.1; Yang, X. H.2; Hu, Q.3; Liu, C. Y.4; Zhou, Z. Q.4; Jiao, B. N.51College of Horticulture and Landscape Architecture, Southwest University, 400715, Chongqing P. R. China2Institute of Pomology of Chongqing Academy of Agricultural Sciences, Chongqing 400712, P. R. China

Yeasts are common spoilage microorganism in commercial orange juice. The rou-tine detection method for yeasts, plate counting technique, is labor intensive and time-consuming. To meet the needs of custom quarantine and market detection, a rapid molecular method was developed to detect spoilage yeasts in orange juice in the present study. 1.5ml orange juice samples artificially inoculated with serial dilu-tions of Saccharomyces cerevisiae in the range of 106-101cfu/ml were centrifuged at 13000 rpm for 3 min. 80 μl improved yeast extraction buffer and 60 mg quartz sand were add to grind the pellet for 3 min by hands with a plastic pestle exactly fitting to 1.5 ml conical tube. Added 270 μl extraction buffer to wash disrupted cells on the pestle into the tube, the samples were incubated at 65 °C for 10 min, then mixed with 2/5 volume of 6M NaCl and equal volume of chloroform-iso-amyl alcohol (24:1). Centrifuged at 13000 rpm for 5 min, DNA was precipitated by absolute ethanol for 10 min, and then centrifuged at 13000 rpm for 5 min again. DNA preparation was washed by 70% ethanol and dissolved in 30 μl sterile ddH2O after being dried. The DAN templates were tested by amplifying the D1/D2 region of 26S rRNA gene by PCR using universal primers NL1 and NL4. The detection limit of yeast cells was 102 cfu/ml juice. The whole detection procedure was finished within 5h.

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T02.235Effect of Potassium Nitrate in Physiological Parameters of Sour Orange (Citrus aurantium L.) Seedlings Exposed to Salinity

Kostopoulou, Z.; Therios, I.; Molassiotis, A.; Tsirakoglou, V.Laboratory of Pomology, Faculty of Agriculture, Aristotle University of Thessaloniki, 54 124, Thessaloniki, Greece

A hydroponic experiment was carried out under controled growth conditions for 30 days with sour orange (Citrus aurantium L.) seedlings to investigate the effects of external potassium nitrate applications to salinity-treated plants with respect to some physiological parameters. Treatments were: (i) Control, plants receiving 50% Hoagland nutrient solution, (ii) Salinity treatment, as for control plus 50 mM NaCl. Salinity treatment was combined with KNO3 supplementary at three con-centrations (5, 10 and 20 mM KNO3). Data indicate that the salt treatment (50 mM NaCl) led to significant decreases in photosynthetic rate, stomatal density, chlorophyll a and b contents, accompanied by significant increases in leaf K+/Na+ ratio. However, content of carbohydrates and proline did not change in the leaves of NaCl-treated plants. The addition of 20 mM KNO3 ameliorated the adverse effects of salinity on chlorophyll content. However, the exogenously applied KNO3 does not affect photosynthetic rate, stomatal density, carbohydrates content and K+/Na+ ratio compared to NaCl exposure. Total phenols content was reduced by external KNO3 applications whereas proline content was suppressed by high (10 and 20 mM) KNO3 application.

T02.236The Distinction Induction Times in Citrus mohammadi M., Mohammadi, M.H.

Mohammadi, S. M. H.; MohammadiJahromi, M. S.1Islamic Azad University Jahrom Branch, No 1Azadi Street Cod, 7418863959, Fars Jahrom, Islamic Republic of Iran

Flower induction is on the base of hormones and toward the condition which they get their requirement factors and some of vegetative buds transfer to sexual buds. If in the time of flower forming and its basic growth and development, a plant use all of its required nutrimental element, that plant can have a rule in the quality and amplitude of flowers and also in the preventions of flower down falling cones quietly the numbers of complete flowers are more and fruit production with good quality can be done much more better. For knowing the exact time of flower in-duction, about 216 citrus trees which were citrus limetta, Citrus reticulata sp. and Citrus sinensis have been examined in maghsood abad garden of Jahrom (of each cultivar 72 trees in 4 different parts of garden and each parts 18 trees). From each trees 4 mature limbs was chose as control treatment and 3 other limbs was gird lied on them in different times (1, 7, 14, 21, 28 Nov, Dec and Jan) the girdling action was done in the 1/5 meters distance from the limbs tips and then eticket action was done after leaves omission. Then after flower existence in the noted cultivars in Feb and March. All of examined and studied trees were observed and with the analyzes of results and observation, it can be said that the flower induction times in the examined cultivars are in 15 Feb till 15 March. Which citrus plants should be in good mood of nutrients.

T02.237Changes in Fruit Quality of ‘Fairchild’ Mandarin Grafted onto Eight Rootstocks and Grown in Desert Climate

Al-Hammam, Y.1; Al-Jalil, A.1; Belhareth, M.1; El-Otmani, M.21National Center for Horticultural Research and Development, Najran, Saudi Arabia2Institut Agronomique et Vétérinaire Hassan II, Complexe Horticole d’Agadir, Morocco

Environmental conditions, pests and diseases, and cultural practices have a great influence on citrus tree growth and production. The Najran region located in the Southern part of Saudi Arabia is unique in its climate (hot and dry), soil (generally sandy) and overall plant growing conditions. In an effort to develop its self suffi-

ciency in agricultural production, the Kingdom of Saudi Arabia has several projects on various crops including citrus. In this perspective, a long term research project was carried out to investigate performance of two mandarin cultivars (‘Kinnow’ and ‘Fairchild’) grafted onto 8 rootstocks [‘Carrizo’ citrange, US-812, Citrus macrophyl-la (CM), ‘Volkamer’ lemon, , Smooth Flat Seville, Gou Tou, Sun Chu Sha (SCS) and ‘Cleopatra’ mandarin] to the desert conditions of this region. The trees were planted in 2004 and cultural practices that are optimal for the region were used. Fruit size, peel thickness, fruit juice content, and juice sugar and acid levels were measured over the maturation period. US-812 gave the smallest fruit size whereas CM and SCS gave the largest fruit. Fruit from CM had the lowest juice content, the lowest sugar level and the lowest acidity. Fruit from US-812 had the greatest sugar content. SCS had the highest acidity. As a result, CM had the highest fruit maturity index (sugar/acid ratio); on the opposite, SCS had the lowest index. Early in De-cember, all combinations had an acidity lower than 1.5%, sugar content greater than 11°Brix and a maturity index greater than 10. Data will be discussed in relation to the agroclimatic conditions of the region and to the consumer preferences.

T02.238An Abscission Agent for Facilitating Mechanical Harvesting of Sweet Oranges in Florida

Ebel, R. C.Southwest Florida Research and Education Center, 2685 Hwy 29 N., Immokalee, FL 34142, Florida, United States

The Florida citrus industry has 193,000 ha of sweet oranges (Citrus sinensis [L.] Osbeck) with about 7% mechanically harvested and the rest harvested by hand labor. Mechanical harvesters currently remove 70-80% of the fruit with the rest being hand harvested. The Florida citrus industry has sought an abscission agent to aid mechanical harvesting and has focused its attention on 5-chloro-3-methyl-4-nitro-1H-pyrazole (CMNP), which has been shown to be effective in loosening fruit and increasing recover rates. However, research has shown that loosening of fruit by CMNP is affected by several factors including method and rates of appli-cation factors and environmental factors, especially rain and air temperature. We have conducted research to develop tools that will improve commercial scheduling of CMNP and maximize its efficacy under a variety of temperature conditions. CMNP requires direct contact on fruit and thus must be applied using spray tech-nology that delivers spray directly to all fruit throughout the canopy. To further define the effect of air temperature on fruit loosening by CMNP, CMNP was ap-plied at 0, 200, or 300 mg·L-1 and 2806 L·ha-1 on various dates during the harvest season on ‘Hamlin’ and ‘Valencia’ sweet oranges. Air temperature had a clear effect on the rate of loosening, with very low loosening when air temperatures were < 15.6 °C. We have also evaluated the rate of drop, which tends to be higher for CMNP-treated fruit. The rate of drop is important for scheduling self-propelled canopy shakers that are equipped to capture fruit on decks and convey the fruit to trucks. We are in the process of developing mathematical models to predict the rate of fruit loosening, as measured by fruit detachment force, and the rate of drop. The models incorporate CMNP concentration and air temperature, and assume complete cov-erage and no rain the first 24 hrs after application.

T02.239Effect of Methyl Jasmonate and Salicylic Acid on Chilling Injury of ‘Eureka’ Lemons

Siboza, X. I.; Bower, J. P.; Bertling, I.Horticultural Science, University of KwaZulu-Natal, Pietermaritzburg, South Africa

Lemons are susceptible to chilling injury when exposed to temperatures below -0.5 °C. South Africa produces and exports lemons to countries around the world. The industry continues to lose large amounts of fruit during postharvest storage due to chilling injury. Exposing lemons to low temperature (-0.5 °C) for a certain period is an obligatory quarantine treatment for disinfestations of Mediterranean fruit fly. However, fruit do not tolerate such temperatures and develop chilling injury, an unsolved problem in the citrus industry. Postharvest application of methyl jasmo-nate and salicylic acid in reducing chilling injury symptoms have been previously

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used in mangoes, guava and peaches. ‘Eureka’ lemons were sterilized, air-dried and dipped in 1, 10 or 50μM of methyl jasmonate or 1, 2 or 2.5 mM of salicylic acid for 30 s and waxed with Avoshine ® and stored at -0.5 ºC for 0, 7, 14, 21, 28, 35, or 42 days, before being transferred to ambient temperature for 7 days. Measurements of fruit weight, ethylene and CO2 production, electrolyte leakage of the rind and total antioxidant capacity/activity, total phenolics and soluble sugars were taken. Fruit did not develop visual symptoms of chilling injury despite the extended cold storage time. No significant differences were found between treatments and cold storage time with respect to electrolyte leakage, ethylene evolution and respiration. Treat-ment with 10 μM methyl jasmonate or 2 mM salicylic acid significantly (P<0.05) reduced fruit mass loss and slowed reduction of total antioxidants during cold stor-age. Therefore, methyl jasmonate and salicylic acid dips can enhance the resistance of fruit to chilling injury probably through an increase in antioxidant levels.

T02.240Effect of Water Stress on Citrus Photosynthesis Characteristic

Xie, S.1,2; Liu, Q.2; Xiong, X.2; Lovatt, C. J.31National Center of Citrus Improvement, Changsha Subcenter, Changsha, 410128, Hunan, China2Collage of Horticulture, Hunan Agricultural University, Changsha, Hunan, China3Department of Botany and Plant Science, University of California, Riverside

Effect of water stress on citrus photosynthesis characteristic was systematically studied by using Yamasitaka, Newhall orange, Sha-tian pomelo as materials The results showed: Chlorophyll content of citrus is significantly decreased by water stress, There are positive relationship between relative water content of soil and the volume of chlorophyll-a/ chlorophyll-b, compare with chlorophyll-b, chlorophyll-a is easy damaged by water stress. Under 20%PC treatment, the net photosyn-thetic rate (Pn) of Sha-tian pomelo, Newhall orange, Yamasitaka were 3.44μmol/m2.s, 1.21μmol/m2.s, 1.47μmol/m2.s respectively, it decreased over 90% compared with control. There are positive relationship between relative water content of soil and net photosynthetic rate (Pn) and Transpiration rate (Tr), when has a negative relationship with stoma resistance (Gs). Under well water condition, the diurnal variation of net photosynthetic rate (Pn) of Sha-tian pomelo, Yamasitaka, Newhall orange present bimodal carve, but the value and appeared time of peak are different among three varieties, and there is a obvious “noon break” phenomenon. Under water stress, the diurnal variation of net photosynthetic rate (Pn) of Sha-tian pom-elo show one peak while Yamasitaka, Newhall orange present two peak. The diurnal variation of net photosynthetic rate (Pn) of Yamasitaka is bimodal carve, under well water, 60% PC and 40% PC treatments. However under 20% PC treatment, Yamasitaka show single carve.

T02.241Contribution of Portugal for the Brazilian Citriculture

Passos, O. S.; dos Santos Filho, W. S.Embrapa Cassava And Fruit Crops, C.P. 007, 44380-000 Cruz das Almas, Bahia, Brazil

This paper reviews the dispersion of the citrus species from the Asian to American continent with emphasis on the contribution of the portuguese for the citriculture in Brazil. The citrus species were originated in the subtropical and tropical areas of Asia and Malay Archipelago. From there it were dispersed, in a slow and gradual way, to other parts of the world. During this dispersion, from their centers of origin, a remarkable agribusiness was developed in a area superior to 7,0 million hectares in more than 100 countries distributed among the latitudes 40th in Northern Hemi-sphere and South, in all the continents.. From China to India, the sweet orange was probably transported by the Malay archipelago, principal route between those countries. With the barbaric invasions, among 350 to 400 A.D.; by the end of the Roman Empire, the diffusion of the citrus species was carried out by the Arabs. Af-ter the Arab domain, the distribution of the citrus species, throughout the European continent, was aided by the action of the Crusades, which began in the beginning of the century XI and to the Portuguese have been credited with introducing the best sweet orange varieties from China, in 1520. This was the first step of what became

the most important way to spread fruit species all over the world. In the Americas, the citrus were not known until Columbus’ arrival. On his second trip to the New World, in 1493, he introduced seeds of sweet orange, lemon and citron into Haiti from the Island of Gomera, one of the Canary Islands. Subsequent introductions were accomplished by Portuguese and Spanish in beginnings of the XVI century. They probably reached the American continent first in Panama, in 1509, and later Mexico, in 1518 and in South America the Portuguese introduced the sweet orange specifically in Brazil, the Island of Cananeia, São Paulo, and in State of Bahia, in 1549. Nowadays, the citrus trees are cultivated widely in all brazilian states. The ´Bahia` orange or Navel orange, originated from a mutation somatic of ‘Seleta’ orange, introduced by the Portuguese, is one of the historic facts more important of the brazilian citriculture. This was the only sweet orange variety cultivated when the citrus industry starts to be an economic activity after the 30´s of the past century. The date of the occurrence is not known but its asexuated propagation was made by a Portuguese gardener who lived in the Cabula neighborhood in Salvador, capital of State of Bahia. From Salvador the Bahia orange was introduced in California and then as Washington Navel orange spread all over the world being considered responsible for the development of the citrus industry in the five continents.

T02.242The Citrus Industry and Its Germplasm Banks in Brazil

Passos, O. S.; Souza, A. D. S.; Soares Filho, W. D. S.; Gesteira, A. D. S.Embrapa Cassava and Fruit Crops, C.P. 007, 44380-000 Cruz das Almas, Ba, Brazil

The citrus industry in Brazil represents a large component of the economic and social sectors of the country. The cultivated area almost 1 million hectares and the production of fruit surpassing 20 million tons are responsibles for the brazilian leadership in the world citrus production and frozen concentrated orange juice.The purpose of this paper is to analyse the status of the citriculture in the produc-ing states, the utilization of scion and rootstocks and the available germplasm. Al-though this leadership some threats to the sustainability of the citrus industry must be considered: the high concentration (around 80% of the national production) in one State (São Paulo) where more than 90% is destined to orange juice processing; the predominance of the combination of `Pera’ orange on `Rangpur` lime and, above of all, the prevalence of diseases, mainly the virotic and the bacterial ones, specially those transmitted by insects. Taking these aspects into consideration, one can appreciate the importance of germplasm banks established in the country for support and contribution to the diversification of the citrus industry. According to the Embrapa Genetic Resources Centre there are three Citrus Active Germplasm Banks (CAGB) in Brazil: first at the Sylvio Moreira Center, Cordeiropolis, São Paulo (2,000 accessions); second at Cassava and Tropical Fruit Crops, Cruz das Al-mas, Bahia (800 accessions) and third at Fruit Crops Research Centre, Taquari, Rio Grande do Sul) (400 accessions). Given to the occurrence of HLB (ex-greening) in São Paulo and citrus canker in Rio Grande do Sul, the only CAGB free of these and other harmful diseases, up to date is that located in Bahia. Due to this comparative advantage efforts are being made to index this germplasm, clean it if necessary and mantain it under screen house. The goal is to mantain up to 1200 plant accessions in 45.0 l containers spaced 2.00 × 2.00 m under cover, which will demand one hectare of land area.

T02.243First Record of Citrus Gummy Bark Viroid (CGBVd) Infecting Sweet Orange (Citrus sinensis) in Egypt

Sofy, A. R.1; Soliman, A. M.2; Mousa, A. A.1; El-Dougdoug, K. A.31Botany and Microbiology Department, Faculty of Science, Al-Azhar University, Nasr City, Cairo, Egypt, 2Phytoplasma Research Section, Plant Pathology Institute, Agriculture Research Center, Giza, Egypt, 3Virology Lab., Agric. Microbiology Department, Faculty of Agriculture, Ain Shams University, Cairo, Egypt

Citrus fruit is one of the major traditional agricultural products of Egypt. Con-straints to fruit production are mainly related to tree decline caused by infection

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with viroids. A total 300 samples of sweet orange varieties (Navelina, Balady and Valencia) with gummy bark symptoms (a line of reddish-brown appeared when the bark of diseased trees was scraped, and gum impregnated tissue can be seen around the circumference and especially near the bud union) as well as non-symptomatic trees of the same cultivars growing in close proximity. Total RNA was extracted from these samples and subjected to dot blot hybridization using HSVd DIG-labeled probe. Sixty five samples out of 300 gave clear positive with HSVd DIG-labeled probe as well as some samples gave doubtful results. Also, 65 samples were tested against CEVd using CEVd DIG-labeled probe. Only 10 from 65 samples selected according to different geographical locations and gave negative results with CEVd DIG-labeled probe were indexed for viroids by inoculation of Etrog citron grafted on sour orange. Ten samples involved 8 trees displaying gummy bark disease and two trees symptomless. Within three months, typical viroid leaf symptoms (petiole wrinkle and mid vein browning) were observed on Etrog citron inoculated with samples from three governorates kalyobiya, Al-Fayom and South Sinai. Electrophoresis under denaturing condi-tions of total RNA extracted from the grafted Etrog citron plants with symptoms, indicated the presence of viroid-like circular low molecular weight (LMW) RNA in all the samples. These circular LMW-RNAs were used in RT-PCR using a set of HSVd specific primers. Amplicons of ~300 bp were obtained in 8 samples with primers specific to Hop stunt viroid (HSVd), while non-symptomatic trees were observed no amplification. So, in order to study the degree of structural variation among Hop stunt viroid, gel-purified RT-PCR product of the viroid was cloned in the EcoRI site of pGEM®-T vector (Promega), then sequenced (Accession No. FJ984562). The viroid Egyptian isolate from diseased sweet orange trees is 299 nucleotides in length and is 100% homology with CVdIIb or Ca902 (Accession No. AF131249). The viroid Egyptian isolate was namely Citrus gummy bark viroid cachexia strain.