In this study, the population structure of the chestnut blight fungus Cryphonectria parasitica in the Aydın Mountains was investigated to make inferences about fungal reproduction and population diversity. A total of 213 C. parasitica isolates from eight subpopulations were used to determine vegetative compatibility (vc) and mating types of the population. Furthermore geostatistical analysis was performed to define the spatial structure of the population. The results showed that the isolates were vegetatively compatible with the European vc types of either EU-1 or EU-12. Both vc types were found in almost all subpopulations, but their frequencies varied depending on location. The results of a PCR assay showed that both mating types of C. parasitica (MAT-1 and MAT-2) exist in the population. MAT-1 comprised 65% of the total isolates, and the ratio of mating types was significantly skewed from 1:1. Genotyping based on combined vc and mating type data revealed four genotypes: EU-1/MAT-1 (28.6%), EU-1/MAT-2 (34.7%), EU-12/MAT-1 (36.2%) and EU-12/MAT-2 (0.5%). Geostatistatical analysis indicated that vc types, mating types and vc/mating genotypes were spatially autocorrelated and clustered in their distributions. Results suggested that C. parasitica could have a clonal population structure that is generated by asexual reproduction. Low vc-type diversity suggests that the C. parasitica population in the Aydın Mountains may be highly suitable to hypovirus invasion, thereby providing a high potential for successful biological control. However, co-occurrence of sexually compatible strains of EU-1 and EU-12 at the same locations in close proximity creates a high risk of increase in vc-type diversity.

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Özet: Bu çalışma, Urla Yarımadasında Çeşme kavununda kurumalara neden olan patojenlerin, yaygınlıklarının ve bulunma oranlarının belirlenmesi amacıyla yapılmıştır. Çalışma kapsamında Çeşme, Urla ve Karaburun ilçelerinde 63 tarlada kavun bitkileri, kurumalarla ilişkilendirilmiş belirtiler olan şiddetli sararma, solgunluk, kök ve kökboğazı çürüklüğü, zamklanma, vasküler doku kararması ve kömür çürüklüğü yönünden incelenmiştir. Hastalık belirtisi gösteren 278 kavun bitkisinden örnekler alınmış ve laboratuvarda izolasyon işlemleri yapılmıştır. Çalışma sonucunda sörvey yapılan tarlaların tümünde kavun kurumalarına rastlanmıştır. Toplam 17 tarlada, hastalık bulunma oranı %50 ve üzerinde bulunmuştur. İzolasyon işlemlerinden 165 adet Fusarium oxysporum (%52), 77 adet Macrophomina phaseolina (%24) ve 77 adet Fusarium spp. (%24) izolatı elde edilmiştir. Patojenisite testlerinde, M. phaseolina izolatlarının tamamı, F. oxysporum izolatlarının %68'i kavunda patojen bulunurken diğer Fusarium spp. izolatları arasında patojen olana rastlanmamıştır.