Varietal Screening of Wheat Genotypes/Varieties against Helminthosporium Leaf Blight (Bipolaris sorokiniana) at Rampur, Chitwan, Nepal
Authors: Aman Bhatta, Dinesh Marasini , Bishal Khadka, Yogendra Raj Upadhya, Sarita Lamichhane, Dipa Shrestha, Anuma Dangol
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Screening of 20 wheat varieties/genotypes obtained From National Wheat Research Program, Bhiarahawa, Nepal, against spot blotch, caused by Bipolaris sorokiniana, was conducted in a RCBD during December 2014 to April 2015 in field of agronomy research block at Institute of Agriculture and Animal Science (IAAS), Rampur, Chitwan, Nepal. Each variety/genotype has 3 plots of 1.25m2 as replication. Disease incidence was recorded and intensity measured by calculation mean area under disease progress curve (AUDPC) from single digit disease scores taken at 78, 83, 88, 93 and 98 days after sowing (DAS) respectively. Yield and yield attributing characters were recorded. Genotypes with AUDPC values from 101-200, 201-400 and 401-600 were categorized as resistant, moderately resistant and susceptible respectively. Spot blotch started to appear after 63 DAS only on RR 21, in many varieties/genotypes it started to appear on an average of 68-69 DAS and in NL 1094 lastly on 82 DAS. The highest AUDPC values of wheat varieties/genotypes 419.26 and TGW 41.10g. Maximum disease was found during last week of March to first week of April as maximum and minimum temperature, rainfall and relative humidity were 340C, 190C, 25.5 mm and 78% respectively. The BL 3623 Gautam varieties/genotypes were resistant. These varieties/genotypes had lower disease and higher yield and yield attributing characters. Therefore they can be used as source or resistance to spot blotch in breeding programs. The variety RR 21 appears most susceptible to spot blotch, which can be used as a susceptible check.