Association Mapping of Seed Yield Related Traits in Mungbean (Vigna radiata (L.) Wilczek)
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Date
2021-07
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CCSHAU, Hisar
Abstract
The experimental material consisting of 80 released and advanced mungbean genotypes were evaluated for
30 morphological and yield traits during kharif and summer seasons of 2018-19 and 2019-20 to ascertain
genetic variability, correlations, genetic divergence and to detect loci controlling yield and yield attributes
by association analysis. Significant amount of variability was observed for all the traits except stem
pubescence, leaflet lobes, leaf shape, premature pod color, pod pubescence and seed color and the genotypes
were characterized and categorized as per DUS guidelines. The narrow differences between PCV and GCV
revealed that the existing variation was mainly due to the genetic factors indicating scope for selection. Most
of the characters exhibited high heritability and low genetic advance indicating control of non additive gene
action; therefore, intermating in early generations of the breeding programme will be helpful. Seed yield per
plant was found positively associated with pod length, number of branches per plant, number of pods per
plant and number of seeds per pod and negatively with yellow mosaic disease.The hierarchical cluster
analysis grouped the 80 mungbean genotypes in 10 clusters. The maximum inter cluster distance was
observed between cluster II and IV followed by IV and IX and I and VI and Cluster II was found best for
most of the traits. Stability analysis revealed differential response of genotypes to the environments. The
estimates of environmental additive effects revealed E-4 (Summer, 2020) as the best for all the seed yield
related traits and the genotypes MH 421, MH 1767, MH 318, MH 560, MH 1706 and MH 1452 were found
stable for seed yield per plant. Out of 164 SSRs, 139 markers amplified with allele size between 100-310 bp
and among these 89 were found polymorphic which generated 317 polymorphic alleles with an average of
3.562 alleles per SSR while the number of alleles at each locus varied from two to seven. Both the Weighted
Neighbour Joining and Population Genetic Structure analyses categorized genotypes in a similar manner
suggesting that all the advanced genotypes may have common ancestral history at some level. On the basis
of pure and admixture model, sub population 1, 2 and 3 were found pure and SP-4 contained admixture.
Polymorphic SSRs, used to estimate the average degree of Linkage Disequilibium (LD) present at the
genome level in 80 mungbean genotypes, disclosed significant LD blocks. Over the four seasons, 38 markertrait
associations were observed significant for seed yield related traits by GLM method and ten marker-trait
associations were found significant for five seed yield related traits viz., days to flowering, days to maturity,
plant height, yellow mosaic disease and number of pods per plant by MLM method which indicated low
phenotypic and genotypic variations in association mapping which may be due to low diversity among the
genotypes and exploitation of less number of markers and genotypes in investigation.