Biological characteristics and transmission rules of the slowly-growing Phytophthora sojae isolate HN-1
The culture characters and pathogenicity of slowly-growing isolate HN-1 of Phytophthora sojae and its single-zoospore progeny were observed and measured,and the transmission rules and culture characters,pathogenicity of the infected cultures from HN-1 were researched through dual culture with other 3 nor-mally-growing isolates.The results showed that the slowly-growing isolate HN-1 of Phytophthora sojae had sig-nificant difference on culture characters,growth rate and oospore production compared with normal-growing iso-lates.HN-1 was confirmed to be weak pathogenic isolate through inoculation in vivo.The characteristic of slowly-growing of HN-1 could be transferred to normal-growing isolates and the cultures through hyphal contact expressed slowly-growing characteristic and their pathogenicity were weakened.