Diversity study of Greengram [Vigna radiata (L.) Wilczek] with morphological and SSR markers
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Date
2023
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Abstract
Greengram [Vigna radiata (L.) Wilczek] belongs to the family ‘Fabaceae’ and subfamily ‘papilionaceae’ is an important grain legume crop in the world. It is the third important pulse crop after chickpea and pigeon pea in India. Although, India is the leading producer of green gram globally but its production and productivity levels are very low to meet the nutrient status of people due to many reasons including lack of superior varieties or hybrids. Evaluation and characterization for genetic variability and identification of diverse genotypes is the first and foremost step in any crop improvement programme. Genetic parameters like GV, PV, GCV, PCV, hbs and GA were estimated in 30 genotypes of greengram collected from NBPGR. A high extent of variability was found for quantitative characters like plant height, number of cluster per plant, pods per plant, seeds per pod & harvest index. Estimates of GCV & PCV were high for characters viz., seed yield per plant, pods per cluster, pods per plant and harvest index. High heritability coupled with high genetic advance as per cent of mean was observed for characters viz., harvest index, yield per plant, pods per plant, cluster per plant, pod per cluster, seed per pod, 100 seed weight, number of primary branches and plant height indicating the role of additive gene action and highlighting the importance of those traits as efficient selection criteria. High extent of variability was found also for qualitative traits like terminal leaf shape, seed colour, seed shape etc. among the genotypes studied. Diversity study using quantitative characters depicted 6 clusters out of which 3 are solitary. Among all the characters studied, 100 seed weight exhibited maximum contribution towards divergence. Cluster II and cluster VI exhibited maximum inter-cluster distance. Hence, it can be suggested that hybridization among the genotypes of these two clusters might give better heterotic combination. Again on the basis of qualitative traits studied, genotypes were grouped into 3 main clusters and 4 solitary clusters applying Jaccard’s similarity coefficient. Accordingly, maximum divergence was observed between the genotype IC-148403 and IC-282094 suggesting their utility in crossing to get better segregant. Out of 30 genotypes, 15 were subjected to SSR (already reported) based polymorphism analysis. Out of the total 22 SSR screened, 10 were polymorphic across fifteen genotypes. The maximum PIC was revealed by primer GMES4400, cp06039 and cp8304 (0.375 each) while minimum PIC among polymorphic markers was shown by primer DMBSSR038 (0.2772). The average value of PIC was found to 0.35744. Accordingly, the genetic diversity pattern of these 15 greengram germplasm under study was estimated by the Jaccard similarity
coefficient. The dendrogram using unweighted neighbour-joining (UPGMA) drawn from the analysis divided 15 genotypes into 3 clusters. Maximum divergence was observed between the genotype IC-76544 and IC-39548 indicating the usefulness of these genotypes in hybridization programme. More number of polymorphic SSR primers will be required for further investigation to get a clear picture of diversity pattern at molecular level. Genotypes viz., IC-76544 and IC-121232 were grouped in the same cluster for quantitative, qualitative as well as SSR studies. Although the diversity at both morphological and genomic level was studied, there is need of further statistical analysis to measure the degree of relationship between the dissimilarity matrixes generated from qualitative, quantitative and SSR marker data.