Incidence of pod and seed infection in two soybean lines differing in resistance to Phomopsis seed decay

Abstract

Two soybean (Glycine max) lines differing in resistance to Phomopsis seed decay were evaluated in field trials, over 3 yr, for time and incidence of pod and seed infection caused by Phomopsis longicolla, Diaporthe phaseolorum var. caulivora and D. p. var. sojae. Pod infection increased linearly with time but OX615 averaged 15% less than Coles at each sample date. Seed infection increased curvilinearly in conjunction with decreasing seed moisture with marked increases between the fifth and seventh weeks after flowering. At maturity, average seed infection was 69% in Coles and 28% in OX615. Key words:Glycine max, soybean, resistance to Phomopsis seed decay