Effect of purple seed stain disease on physical and biochemical traits of soybean

Abstract

Healthy (asymptomatic) and various categories of purple stained seeds of cultivar NRC 7 were utilized to study influence of purple stain disease caused by Cercospora kikuchii on physical and biochemical parameters of soybean seeds. Results indicated that C. kikuchii infected seeds exhibited marked reduction in germination and emergence when 25 per cent or more surface area of seed was stained. Post-emergence mortality was caused when more than 50 per cent of seed area was stained. Single to multiple cracks in seed coat were observed leading to prominent absence of hard seeds. Purple stain has significantly reduced test weight, seed and root vigour, normal seedlings, root and seedling length, speed of elongation and trifoliate leaves in seedlings, and increased dead seeds, abnormal seedlings and electrical conductivity. Loss in seed yield was in the range of 36-80 per cent. It also reduced stearic acid, palmitic acid, linoleic acid, linolenic acid, trypsin inhibitor and protein, and increased oleic acid as well as oil content in seeds of soybean.