investigating resistance of 3 pistachio stocks to rhizoctonia solani ag4

in this study, 99 isolates of rhizoctonia were recovered from root and crown samples of pistachio seedlings, and soil samples were collected from major pistachio orchards in kerman province. results revealed that 96 isolates were multinucleate and 3 binucleate. mnr belonged to ­ag-4. results of the pathogenicity tests carried out in the greenhouse, using pistachio isolates, revealed that all mnr isolates were pathogenic to pistachio. for evaluation of the stock resistance to the disease, 3 stocks including badamy reez (the most common stock in the province), sarakhs and baneh (wild stocks) were used in greenhouse study. for seedling inoculations, 3 isolates of the pathogen with the highest levels of pathogenicity were used. barley grains inoculated with the pathogens were used as inoculum in pathogenicity tests. two weeks after inoculation, disease severity was assessed and the results indicated that baneh and badamy reez were the most and the least resistant stocks respectively.