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    Genetic and pathogenic characterization of Verticillium dahliae isolates from eggplant in Turkey
    (Springer, 2009) Dervis, Sibel; Yetisir, Halit; Yildirim, Hatice; Tok, Fatih M.; Kurt, Sener; Karaca, Fatih
    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 'AydA +/- n SiyahA +/-' 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.
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    Inactivation of Penicillum expansum in sour cherry juice, peach and apricot nectars by pulsed electric fields
    (Academic Press Ltd Elsevier Science Ltd, 2008) Evrendilek, Gulsun Akdemir; Tok, Fatih M.; Soylu, E. Mine; Soylu, Soner
    Inhibitory effects of pulsed electric fields (PEF) on Penicillum expansum inoculated into sour cherry juice, apricot and peach nectars were determined based on germination tube elongation, spore germination and light and scanning electron microscopy (SEM) observations in this study. After inoculation of rate, juice/nectar samples with P. expansum spores at the level of 10(5)-10(6) cfu/mL, the samples were processed by bench scale PEF pulse generator as a function of differing electric field strengths (0, 13, 17, 20, 23, 27, 30 and 34 kV/cm) and processing times (0, 62, 94, 123, 163, 198 and 218 mu s). Results revealed that with an increase in electric field strength and processing time, germination tube elongation and spore germination rate were completely inhibited. Light and SEM observations revealed considerable morphological alterations in fungal conidia such as cytoplasmic coagulation, vacuolations, shrinkage and protoplast leakage. PEF processing of juice/nectars was demonstrated to be effective in inactivating P. expansurn. To our knowledge, this is the first study confirming the inhibitory effects of PEF on germination tube elongation and spore germination rate of P. expansum in fruit juice/nectars. (C) 2008 Elsevier Ltd. All rights reserved.
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    Rootstock potential of Turkish Lagenaria siceraria germplasm for watermelon: Plant growth, graft compatibility, and resistance to Fusarium
    (Tubitak Scientific & Technological Research Council Turkey, 2007) Yetisir, Halit; Kurt, Sener; Sari, Nebahat; Tok, Fatih M.
    The rootstock potential of Turkish Lagenaria siceraria germplasm for watermelon was evaluated. Among 210 accessions, 72 genotypes were selected based on morphological characteristics. Two commercial hybrid rootstocks were also used for comparison. Crimson Tide watermelon cultivar was used as a scion. Emergence rate, hypocotyl morphology, survival rate, and resistance to Fusarium oxvsporurn f. sp. niveum (FON) were investigated. Grafted plants were grown for 3 weeks in order to investigate the effect of rootstocks on plant growth. Leaf number, shoot dry weight, and root dry weight were determined. Emergence rate was ranked between 72% and 100% in collected genotypes. The highest graft compatibility was 99% while the lowest graft compatibility was 70%. All the grafted plants showed better performance than control plants regarding plant growth. All bottle gourd genotypes were tested against known 3 races of FON and all of them showed resistance against it. However, 9 genotypes showed yellowing but reisolation from those plants showed that yellowing was not due to FON. Crimson Sweet watermelon cv. susceptible to 3 races of FON was grafted onto 10 Lagenaria siceraria genotypes with the highest graft compatibility with watermelon. While all grafted plants showed resistance to FON, ungrafted Crimson Sweet watermelon cv. was found susceptible to 3 races of FON. The results showed that Turkish L. siceraria germplasm has powerful rootstock potential for watermelon against Fusarium wilt and it is a good resource for rootstock breeding programs.
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    Vegetative Compatibility and Virulence Diversity of Verticillium dahliae from Okra (Abelmoschus esculentus) Plantations in Turkey and Evaluation of Okra Landraces for Resistance to V. dahliae
    (Tech Science Press, 2020) Tok, Fatih M.; Dervis, Sibel; Yetisir, Halit
    Forty-four V. dahliae isolates were collected from symptomatic vascular tissues of okra plants each from a different field in eight provinces located in the eastern Mediterranean and western Anatolia regions of Turkey during 20062009. Nitrate-nonutilizing (nit) mutants of V. dahliae from okra were used to determine heterokaryosis and genetic relatedness among isolates. All isolates from okra plants were grouped into two vegetative compatibility groups (VCGs) (1 and 2) and three subgroups as 1A (13.6%, 6/44), 2A (20.5%, 9/44) and 2B (65.9%, 29/44) according to international criteria. Pathogenicity tests were performed on a susceptible local okra (A. esculentus) landrace in greenhouse conditions. All isolates from VCG1A and VCG2B induced defoliation (D) and partial defoliation (PD) symptoms, respectively. Other isolates from VCG2A gave rise to typical leaf chlorosis symptoms without defoliation. The obtained data showed that the virulence level of V. dahliae isolates from okra was related to their VCG belongings. Eighteen okra landraces from diverse geographical origins were screened for resistance to VCG2B and VCG1A of V. dahliae. The results indicated that all landraces were more susceptible to highly virulent VCG1A-D pathotype displaying D or PD symptoms depending on their susceptibility levels with a mean disease severity index of 3.52 than to less virulent VCG2B-PD pathotype of V dahliae displaying PD and ND symptoms with a mean disease severity index of 2.52. Significant differences were observed among the landraces; however, none of them exhibited a level of resistance. Okra landraces; corum, Hatay Has and Sanhurfa displayed the lowest level of susceptibility or little tolerance to both D and PD pathotypes. VCG2B of PD was prevailing in the surveyed areas and VCG1A of D was the most virulent of the VCGs identified. Introduction of resistant genotypes to Turkish okra germplasm from different sources and breeding new resistant okra cultivars are critical for the sustainability of okra production.
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    Vegetative compatibility groups in Verticillium dahliae isolates from olive in western Turkey
    (Springer, 2007) Dervis, Sibel; Erten, Latife; Soylu, Soner; Tok, Fatih M.; Kurt, Sener; Yildiz, Mehmet; Soylu, E. Mine
    Verticillium wilt, caused by Verticillium dahliae, is the most serious disease in olive cultivation areas in western Turkey. Two hundred and eight isolates of V. dahliae from olive (Olea europea var. sativa) trees were taken for vegetative compatibility analysis using nitrate non-utilizing (nit) mutants. One isolate did not produce a nit mutant. Nit mutants of 207 isolates were tested against tester strains of internationally known vegetative compatibility groups (VCGs) 1A, 2A, 2B, 3, 4A and 4B, and also paired in many combinations among themselves. One hundred and eighty nine of the isolates (90.9%) were strongly compatible with T9, the tester strain of VCG1A, and thus were assigned to VCG1A. Eight isolates were assigned to VCG2A and four isolates to VCG4B. One isolate was heterokaryon self-incompatible (HSI) and five isolates could not be grouped to any of the VCGs tested. Pathogenicity assays were conducted on a susceptible olive cultivar (O. europea cv. Manzanilla) and a susceptible local cotton cultivar (Gossypium hirsutum cv. Cukurova 1518). Both cotton and olive inoculated with all VCG1A isolates showed defoliating symptoms in greenhouse tests. This is the first report on VCGs in V. dahliae from olive trees in Turkey which demonstrates that VCG1A of the cotton-defoliating type is the most commonly detected form from olive plants in the western part of Turkey.
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    Vegetative compatibility groups of Verticillium dahliae from cotton in the southeastern Anatolia region of Turkey
    (Springer, 2008) Dervis, Sibel; Kurt, Sener; Soylu, Soner; Erten, Latife; Soylu, E. Mine; Yildiz, Mehmet; Tok, Fatih M.
    Eighty isolates of Verticillium dahliae from the southeastern Anatolia region and 20 isolates from the east Mediterranean region from wilted cotton plants were used for vegetative compatibility analysis employing nitrate non-utilizing mutants and reference tester strains of vegetative compatibility groups (VCGs) 1A, 2A, 2B, 3, 4A and 4B. Of the 100 V dahliae isolates, 49 were assigned to VCG1A, 39 to VCG2B, nine to VCG2A and three to VCG4B. Pathogenicity assays were conducted on susceptible cotton cv. Cukurova 1518 in the greenhouse. All VCG1A isolates induced defoliation and all VCG2B isolates caused partial defoliation symptoms. Isolates of VCG2A and VCG4B caused typical symptoms of leaf chlorosis without defoliation. This is the first report on VCGs of V. dahliae in the southeastern Anatolia region of Turkey, which demonstrates that VCG1A of the cotton-defoliating type and VCG2B of the partially defoliating type are prevalent in this region.