Studies on determination of seed-borne fungi in pumpkin

In this study, the identification of the fungi species, which were present in the seed coat and embryo of pumpkin seeds and the determination of the pathogenicity of fungal species were aimed. In this context, seeds of 5 different summer pumpkin (Cucurbita pepo L.) cultivars (Çağlayan, Mert Bey, Sena Hanım, TG22 and TG38) and seeds collected from fruits belonging to 10 different provinces where winter pumpkin (Cucurbita moschata Duch.) were cultivated in Turkey, were used. Among the species, Allophoma labilis and Didymella americana were only detected in the seeds (seed coat and embryo) of the cultivars Mert Bey and Çağlayan, respectively. It was determined that the seeds of both summer pumpkin cultivars and winter pumpkins belonging to different provinces were contaminated with Alternaria alternata, Fusarium equiseti and Fusarium proliferatum although the rates of contaminated seeds differ according to the varieties, provinces and seed parts. The rates of contaminated seed coat with A. alternata were higher than those of embryos in the provinces and cultivars (except TG22) which this species was detected, by exhibiting the highest rate (19.23%) in the seed coats of the samples from Tekirdağ province. The highest rates of seed coat (78.85%) and embryo (63.46%) contaminated with F. equiseti were determined in seeds from Afyonkarahisar province. The highest contamination rate with F. proliferatum (13.46%) was detected in the embryo of TG38. In the pathogenicity tests by treating different isolates of each species to the seed, disease severities in seedling were caused at the rates of 37.14-49.64% by A. labilis, 31.78%-42.50% by A. alternata, 31.29% by D. americana, 14.17-50.00% by F. equiseti and 25.00-51.07% by F. proliferatum.