Study on pathogenicity variation of the different isolates of Verticillium dahliae Kleb. and evaluating the resistance of the several eggplant cultivars to them

Eggplant Solanumm elongena L. of fruit vegetables is grown in warm and tropical regions. This plant has mostly been attacked by different pathogen particularly the causal agent of Verticillium wilt (Verticillium dahliae). This is one of the most important diseases that damaged eggplant and reduced yield and fruit quality up to 50%. There has been little successful in control by the use of fungicides, therefore, the resistance of eggplant varieties studied in this research. For this purpose, first the fungal isolates from different areas under eggplant culture were isolated from vascular tissue in Tehran and Alborz province and then purification and pathogenicity test, 15 isolates obtained in pathogeny potential were evaluated by root dip method of the root of Varamini susceptible cultivar in spore suspension with concentrations of 106 spores per ml. Disease severity index calculated by seven numbered scale of Xiao and Lin 1995, after five weeks. The results showed that V-E-KM-2 isolate obtained from samples of infected plants in MohammadShahr in Karaj, with disease severity of 92 percent were identified most virulent as pathogeny. In evaluation stage of the root resistance of different varieties, 14 common cultured eggplant varieties and the present varieties as pathogenicity method, inoculated with spores of the fungus. Symptoms recording were assessed 35 days after inoculation. The results obtained from the analysis of variance showed that treatments are significantly different in probability level of 1%. The means and resistance evaluation of eggplant cultivars against Verticillium wilt showed seven cultivars of Pasargadae, Volentala, Hybrid Arro, Lady, Sohrab, Yek Beauty (1) and Minabella were tolerant (T) in the range of 31.5 to 49.7 of the percentage of disease index. In this following study, supplementary investigations are essential to introduce tolerant varieties for cultivation in Iran.