Genetic diversity analysis for agro-morphological traits and disease resistance under rainfed conditions in wheat (Triticum aestivum L.)
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Date
2022-12-17
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CSK HPKV, Palampur
Abstract
The present investigation entitled ‘Genetic diversity analysis for agro-morphological traits and disease
resistance under rainfed conditions in wheat (Triticum aestivum L.)’ was conducted at Rice and Wheat Research Centre,
Malan and the Molecular Cytogenetics & Tissue Culture Laboratory of the Department of Genetics and Plant Breeding,
CSK HPKV, Palampur.The objectives were to assess the diversity amongst wheat genotypes using various agro morphological traits and molecular markers, and screening of genotypes for disease resistance at seedling (yellow rust
and brown rust) and adult plant (yellow rust and powdery mildew) stage. The experimental material comprised of 36
wheat genotypes along with four checks viz., HPW 368 (Him Palam Gehun 2), HS 562, Agra Local and LWH (Local
Wheat Hango) were evaluated for different agro-morphological traits in α-Randomized Block Design with three
replications during rabi 2021-22. Sufficient genetic variability was observed for all the traits viz.,days to 50% flowering,
flag leaf area, peduncle length, plant height, tillers per plant, grains per spike, 1000-grain weight, biological yield per
plant, grain yield per plant and harvest index except days to 75% maturity, suggesting the scope of selection for these
traits. High phenotypic coefficient of variation (PCV) and genotypic coefficient of variation (GCV) along with high
heritability and high genetic advance were observed for grain yield per plant and peduncle length, indicating that
selection would be effective for these traits. Grain yield per plant showed significant and positive correlation with flag
leaf area, tillers per plant, grains per spike, 1000-grain weight, biological yield per plant and harvest index. Also,
biological yield per plant and harvest index were observed as the best selection indices for increasing grain yield owing
to high direct and indirect effects of these traits in path analysis. Based on 11 agro-morphological characters, first four
principal components revealed 73.96 % of total variability. D
2
analysis grouped genotypes into five clusters. The highest
inter cluster distance was found between cluster II and V whereas the maximum contribution towards genetic divergence
was made by 1000-grain weight. On the other hand, molecular markers analysis delineated the genotypes into three
clusters. STRUCTURE divided the experimental lines into two major gene pools. On the basis of mean performance,
five genotypes viz., HD 2967, TYRM 1, TYRM 2, SDN 37 and HPW 89 were found superior for grain yield per plant
and related traits. Based on seedling resistance studies against predominant pathotypes of yellow rust (4) and brown rust
(5), TYRM 2 and TYRM 3 expressed very high level of resistance, whereas PBW 677, Raj 4326, TAW 195, TYRM 1,
TYRM 2, TYRM 3 and TYRM 4 appeared to be highly resistant for yellow rust and powdery mildew at adult plant
stage. Conclusively, TYRM 2 and TYRM 3 were found to be highly resistant to yellow rust at both seedling and adult
plant stage, and powdery mildew. These genotypes need further multilocation evaluation over the years or can be utilized
in future hybridization programme.