Author : Suchat Vichitrananda

Summary : Studies were conducted to assess quantitatively and qualitatively yield losses due to bacteria pustule caused by Xanthomonas phaseoli var. sojensis (Hedges) Starr and Burkholder, of four soybean varieties, namely, TK-5, CES-434 and L-114, and Clark 63-bacterial pustule susceptible, intermediate, and resistant varieties, respectively. The study on the relationship of yield loss to different stages of infection (inoculation), namely, at 15 days before flowering, flowering, pod formation and mature pod stages showed that the seed weight, seed volume, protein content, fat content, and per cent germination were reduced at all stages of inoculation in all varieties. The highest reductions in these parameters were observed in plants inoculated at the flowering stage. However, no significant differences in these parameters were observed between inoculations at 15 days before flowering, flowering and pod formation stages, regardless of the variety.