Halit Yetisir

Rootstock resistance to Fusarium wilt and effect on watermelon fruit yield and quality

The potential of grafted watermelon for resistance toFusarium oxysporum f.sp.niveum on some Curcurbitaceae,Lagenaria, Luffa, Benincasa and commercial rootstocks was evaluated. Effects of grafting on yield and quality of diseased plants were evaluated. All grafted plants and rootstocks were resistant to the three known races (0, 1, and 2) ofF. oxysporum f.sp.niveum except watermelon cv. ‘Crimson Tide’, which was susceptible to race 2. Fruit yield was positively (21–112%) affected byLagenaria rootstocks but negatively affected (200–267%) byCucurbita rootstocks when compared with the control. While only minor differences in fruit quality were determined in control and grafted plants onLagenaria rootstocks, the quality parameters for watermelon grafted ontoCucurbita rootstocks were lower than in the control. The reasons for low yield and quality might be due to an incompatibility betweenCucurbita rootstocks and watermelon. These results showed that rootstock influence on disease resistance as well as yield and quality of scion fruit is important in determining the potential use of grafting applications in watermelon.

A new method for haploid muskmelon (Cucumis melo L.) dihaploidization

Three methods for dihaploidization of haploid melon (Cucumis melo L.) plants were evaluated. Ploidy level was determined morphologically and cytologically for plants treated with colchicine. Immersion of in vitro plantlets or single node explants was compared to immersion of soot tips of greenhouse grown plants in a colchicine solution. In addition, application of single drops of colchicine was applied to lateral buds of greenhouse grown plants. Dihaploidization rate by immersion of apical growing point was about 89%, a rate three times greater than in vitro application by immersion of plantlets or their cuttings into colchicine solution. Colchicine treatment of lateral buds by medicine dropper was found to be ineffective in dihaploid production.

Genetic and pathogenic characterization of Verticillium dahliae isolates from eggplant in Turkey

During 2005 to 2007, eggplant fields in 19 provinces from three different regions (western, southern and southeastern Anatolia regions) of Turkey were surveyed for Verticillium wilt. Sixty-seven isolates of Verticillium dahliae from wilted eggplants were collected and used for vegetative compatibility analysis using nitrate non-utilizing mutants and reference tester strains of vegetative compatibility groups (VCGs) 1A, 2A, 2B, 3, 4A and 4B. Among all isolates, 33 (12 from western, 15 from southern and six from southeastern Anatolia) were assigned to VCG2B, 23 (four from western, eight from southern and 11 from southeastern Anatolia) to VCG2A, six (four from southern, one from western, and one from southeastern Anatolia) to VCG4B and five (one from western, one from southern and three from southeastern Anatolia) to VCG1A, whereas VCG3 and VCG4A were not defined among isolates. In order to test if there is a correlation between VCG and pathogenicity in V. dahliae, pathogenicity of 30 isolates, representing the four multimember VCGs, were tested on Solanum melongena cvs. ‘Kemer’ and ‘Aydın Siyahı’ in an unheated greenhouse. All isolates were found to be pathogenic on both cultivars and there was no difference in susceptibility between the two cultivars. VCG4B isolates collectively led to higher vascular discoloration index (VDI) on both cultivars and higher disease severity index (DSI) on ‘Kemer’ compared with other VCGs. Similarly, VCG1A caused lower VDI on both cultivars and lower DSI on ‘Kemer’. Isolates within each of VCGs 1A, 2A and 4B caused similar VDI on both cultivars. Isolates of VCG2B were found to vary in their VDI values on both cultivars. To the best of our knowledge, the present study is the first report of natural infections of eggplant by VCG1A.

Effect of mycorrhizae inoculation on plant growth, yield, and phosphorus uptake in garlic under field conditions

The effect of mycorrhizae species and phosphorus (P) fertilizer on garlic (Allium sativum L.) growth, yield–quality, and P uptake under high P accumulated non-sterile field conditions were studied. Experiments were conducted for two successive years under field conditions of Menzilat soil series (Typic xerofluvent) at the Research Farm of the University of Cukurova (Turkey). Glomus mosseae arbuscular mycorrhizae (AM) were tested on local Urfa genotype of garlic at 0, 40, 80, and 120 kg phosphorus (P2O5) ha−1. In the first year, garlic was inoculated with 1,000 spores per plant, but in the second year, garlic was inoculated with either 1,000 or 2,000 spores per plant. Emergence, plant growth, yield, bulb size, root mycorrhizal infection, and phosphorus uptake of plants were examined. Neither mycorrhizal inoculation nor P2O5 supply increased garlic growth and yield. However, at 0 level of P2O5 application, mycorrhizal inoculation slightly increased plant P uptake. In the second year of the experiment, mycorrhizae significantly increased clove yield. The results revealed that although garlic is mycorrhizal dependent, mycorrhizal inoculation did not contribute to the plant growth and nutrient uptake.

Volatile compounds in the peel and flesh of cucumber (Cucumis sativus L.) grafted onto bottle gourd (Lagenaria siceraria) rootstocks

Summary The objective of this study was to investigate the distribution of volatile organic compounds (VOCs) in the peel and flesh of the cucumber (Cucumis sativus L.) cultivar ‘Çengelköy’ grafted onto different bottle gourd rootstocks, as VOCs play an essential role in fruit quality. Three genotypes of bottle gourd (Lagenaria siceraria; ‘33-35’, ‘33-41’ and ‘46-03’) were chosen as being representative of Turkish bottle gourd germplasm. The VOCs in each rootstock-scion combination were analysed using carboxen-divinylbenzene-polydimethylsiloxane fibres for solid-phase micro-extraction (SPME) and gas chromatography-mass spectrometry (GC-MS). The VOCs (Z)-6-nonenol (21.4 – 28.6%), (E,Z)-2,6-nonadienol (3.2 – 13.0%), (E,Z)-3,6-nonadienol (1.9 – 7.1%), 1-nonanol (4.9 – 7.2%), (E)-2-nonenal (3.9 – 6.6%), (E,Z)-2,4-heptadienal (5.7 – 6.9%), (Z)-6-nonenal (3.6 – 5.4%), (E)-2-hexenal (0.9 – 4.4%), (E,E)-3,5-octadien-2-one (3.2 – 3.5%), and hexanal (1.9 – 3.6%) were the most abundant compounds found in cucumber peel. Grafting had a significant (P ≤ 0.05) effect on the percentage composition of the major VOCs in peel. (E,Z)-2,6-Nonadienal (34.3 – 41.5%), (E)-2-nonenal (15.5 – 19.9%), (Z)-6-nonenal (5.9 - 8.0%), (Z,Z)-3,6-nonadienol (2.6 – 8.4%), (Z)-6-nonenol (2.7 – 7.9%), 3-decyne (2.1 – 3.4%), and (E,Z)-2,6-nonadienol (1.9 – 5.7%) were the most significant volatiles in cucumber flesh. Of these compounds, (E,Z)-2,4-heptadienal, (E,E)-3,5-octadien-2-one, and 3-decyne were identified as cucumber VOCs for the first time. The results showed that the percentage composition of VOCs in the peel and flesh of cucumbers grafted onto bottle gourd ‘33-41’ were closest to those in ungrafted control cucumber, ‘Çengelköy’. Therefore, Turkish bottle gourd genotype ‘33-41’ has high potential as a rootstock for cucumer grafting.

Volatile Compounds and Sensory Properties in Various Melons, Which were Chosen from Different Species and Different Locations, Grown in Turkey

Gas chromatography coupled to mass spectrometry using a static head space technique was applied to analyze the volatile aromatic compounds of various melons collected from different locations in Turkey. Some physicochemical and sensory analyses were also made. A total of 33 volatile compounds were identified. Differences in the physicochemical and sensory properties of various Turkish melon samples were observed. The multivariate analyses by the volatile compounds separated the three varieties into groups successfully. The most abundant volatile compounds as mean value in all melon varieties were ethyl acetate (22.10%), acetaldehyde (13.65%), and ethanol (23.25%). The results showed that Cantaloupe melons were more preferred by panelists, which had relatively high levels of esters being responsible for strong fruit flavor, like melon, as well as high total soluble solid content and low titratable acidity compared with Inodorus and Simama.

A study of genetic diversity in bottle gourd [Lagenaria siceraria (Molina) Standl.] population, and implication for the historical origins on bottle gourds in Turkey

Bottle gourd [Lagenaria siceraria (Molina) Standl.] is one of the oldest cultivated plants, native to Africa and it distributed to over the World. Its dispersal route from Africa to America and Asia is still subject of studies. Similarly, when and how bottle gourd entered into Turkey is not known. In previous studies, bottle gourd germplasm collecting activities were undertaken in the country and the germplasm were analyzed morphologically. Here we report molecular analysis of 60 Turkish bottle gourds along with 31 diverse exotic accessions. Eighth Simple Sequence Repeats and two chloroplast loci of 91 accessions were analyzed. Capillary electrophoresis was used for DNA size fragman separation. The number of alleles per locus ranged from 2 to 13, with a mean of 7. Mean values for expected heterozygosity, observed heterozgosity, and polymorphism information averaged 0.5, 0.13 and 0.50, respectively, thereby sugguesting very low (0.13) genetic diversity in a very diverse population. An unweighted pair group method with arithmetic mean dendrogram was constructed, Indian accessions clearly separated from the rest. Among the remaining samples, neither Turkish landraces grouped together based on their georgraphic origin, nor clear speration occurred according to origin continent. Interestingly, this co-dominant marker analysis shows close molecular allelic profile among bottle gourds originated from far different countries.

Effects of rootstocks on storage and shelf life of grafted watermelons

Watermelon fruits from non-grafted or grafted ‘Crimson Tide’ (CT) and ‘Crisby’ (CR) onto Ferro, RS841, Argentario and Macis rootstocks were compared for their postharvest quality during storage at 7 °C for 21 days and additional 7 days at 21 °C. Non-grafted and grafted CT and CR fruits did not exhibit chilling injury (CI) symptoms, but the 1-2% of fungal decay occurred after shelf life period following storage. Watermelons grafted on Ferro and RS841 rootstocks had higher flesh firmness thicker rind, lower ripening rating, more intense (higher C*) brighter red (lower h° value) color and higher lycopene content after shelf life period following storage, compared to non-grafted fruits. All of the fruit tested by the panelists received high taste scores of >7.9 out of 8.5 at the beginning, but the scores decreased to >6.8 out of 7.7 at the end of shelf life period. Watermelons could successfully be kept for 21 days at 7 °C and additional 7 days at 21 °C. Watermelons grafted on Ferro and RS841 rootstocks had higher postharvest quality, compared to the non-grafted fruits for both cultivars.

Volatile organic compounds in watermelon (Citrullus lanatus) grafted onto 21 local and two commercial bottle gourd (Lagenaria siceraria) rootstocks

Summary Volatile organic compounds (VOCs) are responsible for flavour development in watermelon (Citrullus lanatus). The objective of this study was to investigate the rootstock effects of 21 local bottle gourd [Lagenaria siceraria (Molina) Standl.] accessions collected from the Mediterranean region (Turkey) on the concentrations of VOCs in watermelon over 2 years. The watermelon cultivar ‘Crimson Tide’ was used as the scion and two commercial bottle gourd rootstocks were also used for comparison. The VOCs in each rootstock-scion combination were analysed using static headspace (SHS) and gas chromatography-mass spectrometry (GC-MS). A total of 24 VOCs were identified in watermelon fruit, including 11 aldehydes, seven alcohols, four ketones, one heterocyclic compound, and one acid. Acetaldehyde (25.9 – 39.5% of the total peak areas), propanal (5.0 – 8.3%), 2-propanone (2.5 – 4.9%), pentanal (2.1 – 3.6%), hexenal (14.5 – 22.6%), (E)-2-hexenal (0.4 – 2.3%), 6-methyl-5-hepten-2-one (10.0 – 19.05%), nonanal (1.6 – 4.4%), (Z)-6-nonenal (4.0 – 9.8%), (E)-2-nonenal (0.6 – 2.0%), (E,Z)-2,6-nonadienal (2.1 – 3.7%), (Z)-6-nonenol (1.0 – 3.2%), and (E,Z)-3,6-nonadienol (1.0 – 3.7%) were the most abundant VOCs found in all watermelon scions. There was no significant effect (P ≥ 0.05) of rootstock on the concentrations of acetaldehyde, propanal, pentanal, heptanal, ethanol, 1-pentanol, 2-propanone, 2-pentyl furan, or acetic acid. Propanal, 2-propanone, and acetic acid were identified as VOCs in watermelon for the first time. Hexanal, (Z)-6-nonanal, and 6-methyl-5-hepten-2-one concentrations were strongly affected by rootstock. The results showed that the local bottle gourd accessions 07-06 and 31-09, in particular, were the most promising genotypes in terms of producing favourable VOCs. Except for the local bottle gourd accessions 33-35, 01-17, and 07-04, the other 18 gourds accessions had high potential as rootstocks for breeding programmes in watermelon with regard to desirable VOC concentrations. Rootstock 31-09 should be considered for commercial production in terms of improved disease resistance, fruit yield, and fruit quality.

Gourds: Bitter, Bottle, Wax, Snake, Sponge and Ridge

Bitter gourd, bottle gourd, wax gourd, snake gourd, sponge gourd, and ridge gourd are cultivated and marketed by smallholder farmers, and are important crops in home gardens throughout southern and southeastern Asia. These vegetables provide significant dietary nutrients such as vitamin A and C, iron and calcium. Public sector breeders and germplasm curators release open-pollinated varieties of these cucurbits developed through selection from landraces. Private sector breeders develop F1 hybrid cultivars of these gourds that are popular with growers because of their uniformity, early and total marketable yield, and, in some cases, disease resistance. This chapter reviews the status of germplasm resources for sustained genetic improvement of these cucurbit species. Susceptibility to viruses is currently the major production constraint for these gourds, and systematic evaluation of their germplasm against viruses will be helpful for breeding improved cucurbit lines. The germplasm resources of these gourd species are held in an array of genebanks in several countries and may not be readily available for scientific research or to commercial breeders outside of their respective country. Many accessions of these gourd species listed by the World Vegetable Center and the U.S. Germplasm Resources Information Network are either not available or inactive. More accessions of these gourd species and their relatives need, therefore, to be collected from various regions of the tropics, conserved, and evaluated to ensure continuous genetic gains in breeding programs.