Spot blotch disease resistance and heat stress tolerance in spring wheat (Triticum aestivum L.)

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. Canopy temperature measurements using infrared thermometry, to assess variation in foliar blight resistance along with heat tolerance as an integrative selection criterion. The experiment set was comprising 52 genotypes and arranged in alpha lattice design with two replications in 2017/-2018 Directorate of agricultural research center, Parwanipur, Bara, Nepal. Each plot size was 8 rows of 3 meters long. Three times disease scoring was done in Flag leaf, and Penultimate leaf method and calculated the Area under the disease progress curve (AUDPC). Other data were analyzed by using R software (4.2.2). Canopy temperature, heading days, days to maturity, plant height, number of grains per spike (NGPS), number of tillers per meter square (NTPM), thousand-grain weight (TGW), and grain yield were found highly significant. The genotype 32 was found the highest yielder (5141 kg/ha) and canopy temperature 16.50 C with a 279; 610 F; F-1AUDPC, respectively.