Evaluation of wheat (Triticum aestivum L.) genotypes for spot blotch (Bipolaris sorokiniana Sacc) resistance in terai condition of Nepal

Abstract

Spot blotch caused by Bipolaris sorokiniana is a major disease of wheat in warm and humid regions of Nepal. The fungus has a worldwide distribution but as a pathogen, it is the most aggressive under the conditions of high relative humidity and temperature associated with the low fertility of soils in Nepal. The yield loss due to the disease is very significant in Nepal. This experiment was conducted to identify the genotypes having a good level of resistance against spot blotch. The experiment set was received from CIMMYT comprises 52 genotypes and arranged in alpha lattice design with two replications in 2017/18 at National Wheat Research Program, Bhairahawa, Nepal, and Regional Agricultural Research Station, Parwanipur, Bara, Nepal. Each plot size was 8 rows of 2 meters long. Three times disease scoring was done in the double-digit method and calculated the Area under the disease progress curve (AUDPC). Other data were analyzed by using R software (4.2.2). Heading days, days to maturity, plant height, number of grains per spike (NGPS), number of tillers per meter square (NTPM), mean AUDPC, thousand-grain weight (TGW), and grain yield were found highly significant. The genotype 8HLBSN47 was found the highest yielder (4996kg/ha) with a 304 mean AUDPC value. Seventeen genotypes (15.3%) found the lowest mean AUDPC, Penultimate leaf AUDPC, Flag leaf AUDPC, and the highest number of tillers per square meter, number of grains per spike, thousand-grain weight, and grain yield.