Genetic analysis and association of spot blotch resistance caused by Bipolaris sorokiniana with morphological and yield attributes in bread wheat (Triticum aestivum)

Gyanendra Singh, B S Tyagi, G P Singh, Ravish Chatrath, D P Singh, Jag Shoran

Abstract


A study was conducted during 2005-07 to assess genetic variability in 375 diverse genotypes of wheat (Triticum aestivum L. emend. Fiori & Paol.) for estimates of heritability, genetic advance, direction and magnitude of association and contribution of important morphological and yield attributes with Helminthosporium Leaf Blight (HLB) disease resistance. Analysis of variance revealed significant differences among the genotypes for all 13 traits, thereby indicating presence of sufficient genetic variability in the germplasm tested. High estimates of co-efficient of variation for plant height (9.94 cm), tillers/plant (21.55), grains/spike (13.63), spike weight (20.52g), HLB-1 early stage (27.14). HLB-2 late milk stage (21.823, HLB-3 early dough (17.96) and grain yield [20.45 [unit)] were recorded. The high estimates of heritability were also recorded for days to heading, plant height, spike weight, seeds/plant and HLB-3. Heritability estimates were moderate for remaining attributes, thereby indicating that environment played important role in the expression of these traits. Significant and positive correlation was recorded between days to heading and spike weight. Five traits (days to maturity, tillers/plant. spike length, grains/spike and seeds/plant) showed significant and positive correlation with grain yield. As anticipated, HLB score at all 3 stages recorded negative and significant correlation with grain yield. Besides, negative and significant correlation among HLB, spike length, spike weight and seeds/plant indicated that direct selection for HLB resistance will improve these traits and grain yield in wheat. The significant and positive correlation between days to maturity with plant height; tillers/plant with seeds/plant; spike length with grains/spike; spike weight with seeds/plant; grains/spike with spike weight and seeds/plant; HLB-1 with HLB-2 and HLB-3 and HLB-2 with HLB-3 revealed good scope for indirect selection through these traits for overall improvement in wheat genotypes while targetting spot blotch resistance.

Keywords


Association; Bipolaris sorokiniana; Bread wheat; Correlation coefficient; Disease resistance; Genetic analysis; Heritability; Spot blotch; Triticum aestivum

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