Reactions of selected eggplant cultivars and lines to verticillium wilt caused by Verticillium dahliae Kleb.

Abstract

Verticillium wilt caused by the fungus Verticillium dahliae Kleb. leads to decrease in the yield and quality of eggplant, an economically important vegetable in Turkey. To develop eggplant lines that are resistant to or tolerant to verticillium wilt, this study used cultivars K-1, K-2, K-3, K-4, K-5, K-6, K-7 and K-8 in the studies presented here. The wild species Solanum torvum and Solanum sodemeum; the resistant cultivated forms DK-1, DK-2, DK-3, DK-4 and DK-6; and the cultivar DK-5 were also included in the study. For the pathogenicity tests, an isolate of V. dahliae used was identified by PCR at the Plant Protection Department of the Faculty of Agriculture, A. Menderes University. All the plant materials were tested with this isolate in 2004 and again in 2005. Results from the two years were similar; the lowest disease ratio was obtained from the DK-5 line in both years. F₁ plants were obtained through hybridisation of cultivar K-1 and line DK-5, which were determined to be respectively susceptible and tolerant to V. dahliae. Next, F₂ plants were obtained by selfing F₁. In 2006, cultivar K-1, line DK-5, and F₁ and F₂ plants underwent pathogenicity tests. At the end of the pathogenity test, the disease  severity in cultivar K-1 and line DK-5 was similar to that seen in previous years, whereas the yellowing and wilting values of F₁ plant leaves, as well as stem isolation and reisolation results, were higher than those of F₂ plants. Using a 0 to 5 scale and considering the yellowing area on leaves, the disease severity in F₁ plants was determined to be 38%; the severity value ranged from 2 to 6% in 55% of 200 F₁ plants and from 36 to 44% in the remaining 45%.

Key words: Solanum melongena, Verticillium dahliae, resistance, hybridisation.