Effect of natural seed-borne inoculum of Bipolaris sorokiniana on the seedling emergence and vigour, and early establishment of foliar blight in spring wheat.

The study was conducted to assess the impact of natural seed-borne inoculum levels ofBipolaris sorokinianaon seedling emergence and growth, seedling blight and the early establishment of foliar blight in field. Three levels of seed-borne inoculum (11, 19 and 29%) of one cultivar (Sonalika) and four levels of seed-borne inoculum (5, 35, 65 and 95%) of two wheat cultivars (Sonalika and BL 1473) were evaluated in 2002 and 2003 field experiments, respectively. Seedling vigour study was conducted in the greenhouse in 2003. Seed-borne inoculum levels higher than 35% reduced seedling emergence and seedling vigour substantially, and also increased the seedling blight indicating that the seed-borne inoculum ofB.sorokinianaplayed a crucial role in seedling health and early establishment of the pathogen on wheat. The findings will help to reduce the inoculum pressure of spot blotch and common root rot on wheat. [ABSTRACT FROM AUTHOR]