Nutrient combinations and genotypes for management of Bipolaris sorokiniana under rice-wheat system*

Field trials were conducted to arrive at dose combinations of nitrogen, phosphorus, potash, zinc sulphate and elemental sulphur favouring lowest intesity of spot blotch (Bipolaris sorokiniana) of wheat and highest grain yield, and to identify resistance donors against the disease. Lowest spot blotch intensities of 45.9% in 2001–2002 and 45.5% in 2002–2003 and highest yield of 46.36 and 42.77 q/ha, respectively, were observed under nitrogen, phosphorus, potash, zinc sulphate (21%) and elemental sulphur (32.0%) combinations of 120:60:40:25:25 kg/ha, respectively. It was followed by and was at par with 120:60:40:25:0 combination which gave spot blotch intensities of 46.2 and 49.9% and yields of 45.83 ad 41.24 q/ha. Application of only nitrogen and phosphorus resulted in highest disease intensities of 54.4 and 77.0% and lowest yields of 37.25 and 29.75 q/ha. Out of 354 genotypes, one, NIDW 354 proved resistant and 87 moderately resistant.