Screening for Resistance Sources to Phytophthora Root Rot in Soybean

Phytophthora root rot,incited by Phytophthora sojae,is a destructive disease of soybean.The disease has occurred in several soybean-producing regions in China,and caused heavy losses in some regions.Cultivar resistance has been the most effective way to control Phytophthora root rot.The aim of this study was to screen effective resistance sources to P.sojae for disease control and resistance breeding.One hundred and twenty soybean cultivars or lines from 11 provinces in china were evaluated for their responses to 10 strains of P.sojae using the hypocotyls inoculation technique.One hundred and ten cultivars or lines were identified having resistance to 1-10 strains of the pathogen.The most abundant resistance diversity was occurred in cultivars or lines from Henan province,followed by from Anhui,Hubei and Shanxi province.One hundred and twenty cultivars or lines elicited 57 different reaction types with the 10 strains of the pathogen.Among them 4 reaction types accorded to that of single gene,seven reaction types were consistent with two-gene combinations,and the others were new reaction types.Some cultivars or lines possibly carry new Phytophthora resistance genes that are effective to control Phytophthora root rot of soybean in China.