Abstract
The effect of the infestation with the soybean cyst nematode (SCN) Heterodera glycines on the incidence of Brown Stem Rot (BSR) in adzuki bean (Vigna angularis) caused by Phialophora gregata f. sp. adzukicola was examined under greenhouse conditions. Two races (races 1 and 2) of P. gregata and two adzuki bean cultivars (Erimo-shozu susceptible to both races 1 and 2, and Kita-no-otome susceptible to race 2 but resistant to race 1) were used for these experiments. The enhancement of BSR severity by SCN was observed irrespective of adzuki bean cultivars or P. gregata races, although this phenomenon was not evident when the severity of BSR without SCN infestation was high. No breakdown of Kita-no-otome's resistance to race 1 by the infestation with SCN, however, was observed at all. In the susceptible cultivar Erimo-shozu, the number of propagules of the inoculated fungus in stems and roots increased by SCN infestation, whereas in the resistant cultivar Kita-no-otome the fungus was not detected even under SCN infestation.
