Sources of genetic resistance against newer epidemic groups of spot blotch pathogen B. sorokiniana of wheat.

摘要

Spot blotch caused by B. sorokiniana is the most severe disease of wheat in South-East Asia, after rusts. A study was undertaken with the view of finding out reliable sources for genetic resistance against the emerging isolates of the pathogen that may cause epidemic in future; if the current population is controlled though resistance breeding.Five varieties known for the resistance against spot blotch viz. Yangmai#6; Ning 8201; Chirya-3; HUW-234; HUW-468 and a susceptible variety; Sonalika were planted under controlled conditions. Five groups of B. sorokiniana were cultured and a bead ofmycelium was placed on the leaf of each variety at the anthesis complete stage. Disease symptoms were recorded in modified 1-5 scale. Yangmai#6 was found to show least susceptibility against the fungal variability and was identified as the potential resistant parent for future wheat breeding programs. Chirya-3 was rated as second most desirable parent. Among B. sorokiana isolates. Group in of pathogen was identified as the most potential group after Group I to overcome the resistance of wheat genotypes.