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Öğe Analysis of genetic diversity of Sclerotinia sclerotiorum from eggplant by mycelial compatibility, random amplification of polymorphic DNA (RAPD) and simple sequence repeat (SSR) analyses(Taylor & Francis Ltd, 2016) Tok, Fatih Mehmet; Dervis, Sibel; Arslan, MehmetThe genetic diversity and pathogenicity/virulence among 60 eggplant Sclerotinia sclerotiorum isolates collected from six different geographic regions of Turkey were analysed using mycelial compatibility groupings (MCGs), random amplified polymorphic DNA (RAPD) and simple sequence repeat (SSR) polymorphism. By MCG tests, the isolates were classified into 22 groups. Out of 22 MCGs, 36% were represented each by a single isolate. The isolates showed great variability for virulence regardless of MCG and geographic origin. Based on the results of RAPD and SSR analyses, 60 S. sclerotiorum isolates representing 22 MCGs were grouped in 2 and 3 distinct clusters, respectively. Analyses using RAPD and SSR markers illustrated that cluster groupings or genetic distance of S. sclerotiorum populations from eggplant were not distinctly relative to the MCG, geographical origin and virulence diversity. The patterns obtained revealed a high heterogeneity of genetic composition and suggested the occurrence of clonal and sexual reproduction of S. sclerotiorum on eggplant in the areas surveyed.Öğe Antifungal activity of essential oils against three vegetative-compatibility groups of Verticillium dahliae(Springer, 2010) Arslan, Mehmet; Dervis, SibelThe antifungal activities of volatile phase effects of essential oils from Origanum onites, O. syriacum, O. minutiflorum, O. vulgare, O, marjorana, Thymus vulgaris, T. serpyllum, Rosmarinus officinalis, Salvia officinalis and Micromeria fruticosa were evaluated for their ability to inhibit growth of three vegetative compatibility groups (VCGs) of Verticillium dahliae. Carvacrol was the main component of O. onites, O. minutiflorum and O. vulgare essential oils, while gamma-terpinene was the main component of O. syriacum. P-cymene and thymol were the dominant component of T. vulgaris and T. serpyllum. beta- thujone and l-camphor were the main component of S. officinalis. Polegone and isomenthone were the dominant components of M. fruticosa essential oil. Based on the in vitro test, the degree of fungistatical effects can be ranked in the following order of inhibition: O. syriacum = O. onites = O. minutiflorum = O. vulgare = T. vulgaris > T. serpyllum > M. fruticosa > S. officinalis = O. marjorana > R. officinalis. The essential oils of S. officinalis, O. marjorana and R. officinalis displayed moderate antifungal activity, that increased with increasing concentrations. Among the VCGs, VCG2A and VCG4B were found to be highly sensitive to the essential oils. The essential oils of O. syriacum, O. onites, O. minutiflorum, O. vulgare and T. vulgaris were the most efficacious, demonstrating strong antifungal activity against all of the tested VCGs of V. dahliae at relatively low concentrations and they could find practical application as natural fungicides in the prevention and protection of plants from V. dahliae infections.Öğe Corm and root rot of Colocasia esculenta caused by Ovatisporangium vexans and Rhizoctonia solani(Ars Docendi, 2014) Dervis, Sibel; Soylu, Soner; Serce, Cigdem UlubasOvatisporangium vexans (de Bary) Uzuhashi, Tojo & Kakis. and Rhizoctonia solani Kuhn were isolated from the decayed parts of roots and corms of wilted taro (Colocasia esculenta (L.) Schott.) plants. Although both pathogens were identified according to morphological and pathogenicity characteristics, O. vexans identification was further confirmed based on the internal transcribed spacer (ITS) sequences of 18S ribosomal RNA (rRNA) and 28S rRNA genes using the ITS6 and ITS4 primers. Early symptoms on leaves appeared as pale yellow color, partial rolling of leaf margins and withering of seedlings. Rotting or decay started at the collar region and it spread to roots and corms. In severe cases, the collar region broke off and the seedling collapsed. Inoculating these isolates separately into mature taro plants and corms resulted in symptoms similar to root and corm rots observed on naturally infected plants. Both disease agents were re-isolated from the inoculated tissues. Since symptoms caused by co-inoculation of O. vexans with R. solani together were more severe, combination of two pathogens induced the greatest plant mortality. This is the first report of corm and root rot disease caused by O. vexans and R. solani complex on taro plants in Turkey. This is also the first record of O. vexans in Turkey.Öğe Determination of prevalence and incidence of fungal disease agents of pea (Pisum sativum L.) plants growing in Amik plain of Turkey(Gaurav Soc Agricultural Research Information Centre-Aric, 2011) Soylu, Soner; Dervis, SibelDuring spring 2008 growing season, quantitative disease surveys were conducted to identify the fungal disease agents causing root-foot rot and foliar diseases of pea (Pisum sativum L.) plants growing in different fields in Amik Plain of Hatay province of Turkey. Disease surveys were conducted at three major plant growing stages such as post-emergence (seedling stage), flowering and fruiting-harvesting stages. The disease survey was conducted in randomly selected pea fields in major pea-growing locations. The results of fungal isolations from diseased pea roots taken at regular intervals over the entire growth period have indicated that the most frequently encountered and widespread soil-borne fungal disease agents were Fusarium oxysporum, Rhizoctonia solani, Sclerotinia sclerotiorum, Thielaviopsis basicola and Pythium spp. causing foot, root and collar rots which were found at the seedling stages of pea plants growing especially in fields which have shallow groundwater problems. Observation in several pea fields showed that Ascochyta blight caused by Mycosphaerella pinodes, leaf and pod spot caused by Ascochyta pisi, and Alternaria leaf and stem spot caused by Altemaria alternata were the most frequently observed (55.0, 67.0 and 47.0% of the fields inspected, respectively) foliar fungal disease agents at both the flowering and fruiting stages. Phoma medicaginis var. pinodella was also observed and isolated from necrotic pods. Incidence and severity of the A. pisi were especially higher on local population of plant variety which produces small pods (spring type). Originates of pea cultivars seeds sown in the region were unknown by the local growers. Powdery mildew (Erysiphe pisi) and downy mildew (Peronospora viciae) were observed on local varieties with minor importance.Öğe Effect of entomopathogenic fungus, Lecanicillium lecanii (Sordariomycetes: Hypocreales) on some phytophagous Hemiptera species(Entomological Soc Turkey, Ege Univ, 2014) Telli, Selda; Dervis, Sibel; Yigit, AbdurrahmanThis study evaluates the entomopathogenic fungus, Lecanicillium lecanii (Sordariomycetes: Hypocreales) for prevalence in citrus orchards of Hatay and effectiveness in controlling some phytophagous Hemiptera species. Experiments were conducted under both field conditions and laboratory conditions at 25 +/- 3 degrees C and 80 +/- 5% relative humidity (RH) under 16: 8 hour L: D photoperiod using 1x10(7) conidia ml(-1) concentration of L. lecanii. Infected individuals were counted 5 to 10 days after inoculation. In laboratory conditions, the average mortality due to L. lecanii was 47.54% (23.03-74.55%) on Coccus hesperidum L. (Hemiptera: Coccidae), 61.42% (10.64-100%) on Aphisgossypii Glov., 84.02% (57.39-100%) on Macrosiphum rosae L. (Hemiptera: Aphididae) and 46.63% (22.35-77.36%) on Bemisia tabaci Genn. (Hemiptera: Aleyrodidae). The fungus did not colonize on Ceroplastes floridensis Comst. (Hemiptera: Coccoidae) and Planococcus citri Risso (Hemiptera: Pseudococcidae) at all. The findings revealed that entomopathogenic fungus under field conditions was found to be effective on C. hesperidum and M. rosae resulting in 78.05% (50.25-87.76%) and 78.82% (26.46-100%) mortality, respectively; there was no effect on C. floridensis. It can be suggested that the incorporation of this entomopathogenic fungus into the agricultural areas would be useful in terms of integrated pest management strategies.Öğe First report of Phytophthora crown and root rot of cherry caused by Phytophthora palmivora in eastern Turkey(Taylor & Francis Inc, 2015) Turkolmez, Sahimerdan; Ciftci, Osman; Serce, Cigdem Ulubas; Dervis, SibelCrown and root rot or decline is an increasing problem on sweet cherry in Mardin, Malatya, Elaz and Diyarbakr provinces in eastern Turkey. A survey was carried out during 2012-2014 in 120 commercial cherry orchards for disease symptoms, which included poor growth with sparse off-colour foliage, reddish-brown discolouration of the crown and roots, wilting and dieback of the canopy, and in many cases, tree death. Fifty-eight Phytophthora isolates obtained during the course of this 3-year survey were examined and identified as Phytophthora palmivora on the basis of morphological characteristics. BLAST analysis of ITS region sequences of rDNA of five isolates revealed 99-100% identity with reference isolates of P. palmivora from GenBank and Phytophthora database. Isolates of P. palmivora were pathogenic on 12-month-old potted Mahaleb' cherry (Prunus mahaleb L.) rootstock seedlings that were wound-inoculated on the roots and on the crown. Inoculated plants expressed similar symptoms to those observed in the field and almost all infected plants died within 3 months after transplanting. This study demonstrated that P. palmivora is the causal agent of cherry decline in eastern Turkey. To our knowledge, this is the first report of P. palmivora on this host plant. ResumeLa pourriture du collet et des racines, ou deperissement, constitue un probleme croissant chez le cerisier sauvage dans les provinces de Mardin, de Malatya, d'Elaz et de Diyarbakr de l'est de la Turquie. Une etude a ete menee de 2012 a 2014 dans 120 vergers commerciaux afin de deceler les symptomes de la maladie qui incluent la croissance mediocre accompagnee d'un feuillage clairseme de couleur atypique, la coloration brun-rougeatre du collet et des racines, le fletrissement et le deperissement de la cime et, dans plusieurs cas, la mort de l'arbre. Durant les trois annees qu'a dure cette etude, 58 isolats de Phytophthora ont ete examines et identifies, sur la base de leurs caracteres morphologiques, en tant que Phytophthora palmivora. L'analyse de type BLAST des sequences de l'espaceur transcrit interne de l'ADNr de cinq isolats a revele un taux d'identite de 99% a 100% par rapport aux isolats de reference de P. palmivora provenant de la GenBank et de la Phytophthora database. Les isolats de P. palmivora etaient virulents a l'egard de jeunes plants en pots de 12 mois sur porte-greffe de cerisier Mahaleb' (Prunus mahaleb L.) dont des blessures aux collets et aux racines avaient ete inoculees. Les plants inocules ont affiche des symptomes semblables a ceux observes sur le terrain, et presque tous les plants sont morts en moins de trois mois apres avoir ete transplantes. Cette etude a demontre que P. palmivora est l'agent causal du deperissement des cerisiers dans l'est de la Turquie. Pour autant que nous le sachions, il s'agit de la premiere mention de P. palmivora s'attaquant a cette plante hote.Öğe First report of Verticillium dahliae causing Verticillium wilt on avocado (Persea americana) in Turkey(Springer, 2022) Tok, Fatih Mehmet; Dervis, Sibel[Abstract Not Available]Öğe Gall production on hawthorns caused by Gymnosporangium spp. in Hatay province, Turkey(Springer, 2010) Dervis, Sibel; Dixon, Linley; Doganlar, Mikdat; Rossman, AmyThree hawthorn and related rust diseases caused by Gymnosporangium confusum on Crataegus monogyna, Gymnosporangium clavariiforme on Crataegus orientalis and Gymnosporangium sabinae on Pyrus communis were detected in Hatay province, Turkey. G. confusum was also found causing telial galls on Juniperus communis. G. confusum and G. clavariiforme produced aecial horns on overwintered galls on hawthorn twigs from May to June. The production of galls caused by Gymnosporangium on the secondary host is unusual. Portions of the nuclear ITS and LSU rDNA were sequenced for all three species of Gymnosporangium for use as a species barcode; sequences were deposited in GenBank. Sequence data from G. clavariiforme and G. sabinae matched those in GenBank; however, this is the first study to deposit sequence data from G. confusum to GenBank. The life cycles of G. confusum and G. clavariiforme are discussed along with implications for disease control.Öğe 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, FatihDuring 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.Öğe HOST SELECTIVE VIRULENCE, TEMPERATURE RESPONSE AND GENETIC DIVERSITY IN MACROPHOMINA PHASEOLINA ISOLATES FROM SESAME AND PEANUT IN SOUTHERN TURKEY(Parlar Scientific Publications (P S P), 2018) Tok, Fatih Mehmet; Dervis, Sibel; Arslan, MehmetIn this work, host specificity (comparing virulence levels on diverse hosts), temperature response as a physico-morphological characteristic, and genetic diversity of 40 M. phaseolina isolates from sesame and peanut plants with different geographic origins were evaluated. Sesame and peanut isolates of M. phaseolina performed different levels of virulence on maize, watermelon, melon, peanut, and soybean. The temperatures between 25 and 30 degrees C were the optimum temperatures for colony size of isolates from sesame and peanut. A temperature of 25 degrees C was optimal for only 26 isolates (65%), but 30 degrees C was optimal for 39 isolates (97.5%). UPGMA clustering of data indicated that the Sesame and peanut isolates displayed various levels of genetic similarity within a range of 0.79 to 1.0 similarity coefficient index in three major cluster groups. With a few exceptions, isolates from the same or close locations tended to group together.Öğe Identification and incidence of seed-borne fungal disease agents on bottle gourd (Lageneria siceraria) seeds(Gaurav Soc Agricultural Research Information Centre-Aric, 2010) Dervis, Sibel; Soylu, Soner; Yetisir, HalitSeed-borne fungal diseases are major biotic constraints to seeds. This study was conducted to determine identification and incidence of seed-borne fungal disease agents on seeds of different bottle gourd [Lageneria siceraria (Mol.) Standl.] genotypes which were collected from different parts of Turkey bottle gourd seeds. Using agar plate and blotter method as recommended by ISTA, the seed-borne mycoflora of 21 different samples of bottle gourd seeds collected from infested plants growing in the different parts of Turkey was investigated. Agar plate method yielded greater number of fungi followed by blotter method. The occurrence and average per cent incidence of fungi in seed samples tested revealed that Macrophomina phaseolina, Fusarium oxysporum, Epicoccum purpurascens and Sordaria fimicola were the most frequently isolated seed-borne fungal agents from 70.0, 10.0, 9.5 and 4.6% seed lot samples of bottle gourd, respectively. The sources of primary inoculum in seeds are still not well documented but indications suggest that keeping bottle gourd fruits in fields for maturations play an important role in disease transmission from soils. Seed treatment may prove useful as a part of an integrated disease management approach based on improved resistance and good agronomy.Öğe Leaf blight caused by Didymella glomerata on blackberry in Turkey(Taylor & Francis Ltd, 2024) Dervis, Sibel; Serce, Cigdem Ulubas; Altunbas, Bilge Dagdelen; Unlu, Nida; Pamukcu, GozdemThe cultivation of blackberries has recently increased in Turkey, despite the fact that wild blackberry types have grown almost everywhere in the country. During the summer of 2011, leaf blight symptoms were observed in a blackberry vineyard in Karlisu, as well as on wild blackberry plants in Altinozu, Hatay province, Turkey. Based on morphology, fungal isolates obtained from these blighted leaf margins shared similar morphological characteristics and were tentatively identified as Didymella glomerata. To confirm the morphologic identification, the nucleotide sequences of a representative isolate's ITS, LSU, and tub2 regions of DNA were used. The sequences of three regions were 99-100% identical to D. glomerata isolate sequences in GenBank. Healthy blackberry suckers of the thornless blackberry cultivars 'Triple Crown' and 'Chester' grown in pots were inoculated with spore suspension on foliar parts under greenhouse conditions for pathogenicity testing. D. glomerata was extremely virulent, causing severe leaf blight in both blackberry cultivars. D. glomerata was constantly isolated from inoculated plants' leaf lesions. This is the first report of D. glomerata infection of blackberry, a novel host for this pathogen in Turkey and around the world. More research into the biology and management of the disease is required.Öğe OCCURRENCE OF ISARIOPSIS LEAF SPOT OR BLIGHT OF VITIS RUPESTRIS CAUSED BY PSEUDOCERCOSPORA VITIS IN TURKEY(Univ Agronomic Sciences & Veterinary Medicine Bucharest - Usamv, 2017) Tok, Fatih Mehmet; Dervis, SibelIn mid-autumn 2013, a disease of Vitis rupestris affecting 30 to 50% of the plants was observed in an orchard of the Kirikhan district of Hatay province in the east Mediterranean region of Turkey. Symptoms included presence of initially tiny and angular chlorotic halos but latterly large black spots. On the spots, cercosporoid structures were present. Based on cultural and morphological characteristics of the consistently isolated fungus and pathogenicity tests, the causal agent of this leaf spot or blight was identified as Pseudocercospora vitis. This appears to be the first report of P. vitis on V. rupestris in Turkey. Since Isariopsis leaf spot caused by P. vitis can also affect grapevines (V. vinifera), it might negatively impact orchards and vineyards in the future and might be considered a potential threat to Turkish grapevine production.Öğe Pathogenic races and inoculum density of fusarium oxysporum f.sp niveum in commercial watermelon fields in southern Turkey(Priel Publ, 2008) Kurt, Sener; Dervis, Sibel; Soylu, E. Mine; Tok, F. Mehmet; Yetisir, Halit; Soylu, SonerSystematic surveys for Fusarium oxysporum f.sp. niveum (Fon) were conducted in a total of 141 fields in the watermelon-growing areas of the Mediterranean and southeastern Anatolia regions of Turkey in 2004 and 2005. The mean incidence and prevalence of the disease were higher in the southeastern Anatolia region than in the Mediterranean region. Maximum disease incidence during the 2-year survey was 46.3%. However, mean disease prevalence ranged from 27.3% to 63.6% in southern Turkey. Of the 33 isolates of Fon recovered, 19 were recovered from Adana, two from Mersin, one from Gaziantep, four from Sanhurfa, five from Adiyaman, one from Batman, one from Diyarbalur. The physiological race of each isolate was determined by the disease reaction in five differential watermelon cultivars (Citrullus lanatus (Thunb.) Matsum. & Nakai). Of the isolates recovered from the Mediterranean region, 47.6% were identified as race 0, 38.1% as race 1, and 14.3% as race 2. Among the 12 isolates recovered from the southeastern Anatolia region, four isolates were identified as race 0, and eight isolates as race 1. Race 2 was not detected in this region. This is the first report of Fon races 0 and 1 in southeastern Anatolia. The population density of Fon in both the Mediterranean and southeastern Anatolia regions ranged from 116.1 to 4444.7 CFU g(-1) of soil. The mean inoculum density was much higher in watermelon-growing areas in the southeastern Anatolia region in comparison with the Mediterranean region, with a mean inoculum density of 1547.2 CFU g(-1). Race 0 and race 1 were the most prevalent races in the fields with the mean highest and lowest inoculum density, respectively.Öğe Phytophthora Crown and Root Rot of Apricot Caused by Phytophthora palmivora in Turkey(Wiley, 2015) Turkolmez, Sahimerdan; Ciftci, Osman; Canihos, Ercan; Serce, Cigdem U.; Dervis, SibelForty-nine Phytophthora isolates were obtained from roots and crown of apricot trees with symptoms of decline grown in commercial orchards in Malatya, Elaz and Diyarbakr provinces, Turkey, in 2011 and 2013. All of the recovered isolates were identified as Phytophthora palmivora on the basis of morphological characteristics. Blast analysis of ITS region sequences of rDNA of 5 isolates revealed 100% identity with a reference isolates of P.palmivora from GenBank. Isolates of P.palmivora were pathogenic on 12-month-old wild apricot rootstock Zerdali' plants that were wound inoculated on the roots and on the crown. This study demonstrated that P.palmivora is the cause of the crown and root rot found on apricot in Turkey. To our knowledge, this is the first report of P.palmivora on this host plant.Öğe Production of antioxidant and oxidant metabolites in tomato plants infected with verticillium dahliae under saline conditions(Springer Singapore, 2017) Dikilitas, Murat; Yucel, Nurcan; Dervis, SibelThe objective of this research was to study the levels of antioxidant and oxidant metabolites such as total protein, total soluble sugars, proline, peroxidase, catalase, malondialdehyde, anthocyanin and phenol contents in tomato plants (Lycopersicon esculentum Mill. cv. Ailsa Craig) inoculated with Verticillium dahliae under various NaCl concentrations (50, 100, 200 and 250 mmol l-1). V. dahliae alone resulted in increases in oxidant (malondialdehyde and phenol) and antioxidant metabolites (proline, anthocyanin and sugar) as well as in antioxidant enzymes (catalase and peroxidase). However, the pathogenic effect of V. dahliae increased with the increase of NaCl stress and resulted in depletion of antioxidant metabolites and enzymes after 150 mmol l-1 NaCl level, while oxidant levels showed an increased trend. Results suggest that V. dahliae could be able to survive under high salt stress conditions and cause combined stress that affect the resistance of the resistant cultivars and reduce crop yield. © Springer Nature Singapore Pte Ltd. 2017. All rights reserved.Öğe Survey of Turkish Strawberry Production Areas for Soil-borne Fungal Diseases(Amer Soc Horticultural Science, 2015) Bildik, Mehmet Naci; Serce, Cigdem Ulubas; Dervis, Sibel; Turkolmez, Sahimerdan; Ciftci, Osman; Serce, Sedat[Abstract Not Available]Öğe 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, HalitForty-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.Öğe Vegetative compatibility groups and pathogenicity of Verticillium dahliae isolates from watermelon in Turkey(Academic Journals, 2009) Dervis, Sibel; Yetisir, Halit; Tok, Fatih Mehmet; Kurt, Sener; Karaca, FatihIn this study, surveys were carried out for Verticillium wilt in watermelon fields (262 fields) in 13 provinces from five regions of Turkey. The proportion of fields having wilted plants was 40%. Verticillium dahliae was isolated from 15.2% of the fields showing wilted plants. At the end of surveys, 16 V. dahliae isolates (each from a different wilted field, collected from eight provinces of the Aegean, Central Anatolia, Marmara, Mediterranean and Southeastern Anatolia Regions) were obtained and used for vegetative compatibility analysis using nitrate non-utilizing mutants and reference isolates belonging to vegetative compatibility groups (VCGs) 1A, 2A, 2B, 3, 4A and 4B. Eleven V. dahliae isolates from Adana, Adiyaman, Balikesir, Diyarbakir, Konya and Mersin provinces were assigned to VCG2B, two from Mersin province to VCG2A, one from Balikesir province to VCG4B and two from Manisa and Aydin provinces to VCG1A whereas VCG3 and VCG4A were not defined among the isolates. To reveal a possible correlation between VCG and pathogenic group in V. dahliae, pathogenicity of all isolates representing the four VCGs were tested on three watermelon cultivars (Citrullus lanatus cultivars 'Crimson Sweet', 'Crimson Tide' and 'Crisby') and a susceptible cotton cultivar (Gossypium hirsutum cultivar Cukurova 1518') in a greenhouse. In watermelon cultivars, most VCG2B isolates caused significantly more severe symptoms than VCG4B, VCG2A and VCG1A. VCG4B isolate was more virulent on all watermelon cultivars than both VCG1A isolates. The isolates within VCG2A and VCG1A caused similar virulence patterns on 'Crimson Sweet' and 'Crimson Tide' cultivars but for 'Crisby' VCG1A did not cause any leaf symptom. Virulence to watermelon cultivars varied only among the isolates within VCG2B. Significant differences in virulence to cotton were observed between isolates from different VCGs except the similarity between VCG2A and VCG4B. The results expose that the population of V. dahliae from watermelon in Turkey is heterogeneous (four different VCGs among 16 isolates) but VCG2B seems to be a more specialized form for this host in Turkey.Öğe 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. MineVerticillium 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.
