Genetic Diversity Analysis in Indian Mustard (Brassica juncea L. czern and coss) through D2 and SSR marker
Loading...
Date
2021-09
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
SARDAR VALLABHBHAI PATEL UNIVERSITY OF AGRICULTURE AND TECHNOLOGY, MEERUT- 250110 (U.P.),
Abstract
ABSTRACT
Name : Anjali Id. No. : 4844
Major : Genetics and Plant Breeding Degree : M.Sc (Ag.)
Minor : Ag. Biotechnology
Department : Genetics and Plant Breeding
Advisor : Dr. Mukesh Kumar
Thesis title : "Genetic Diversity Analysis in Indian mustard (Brassica juncea L. Czern and Coss) through D2 and SSR markers"
The present investigation was carried out to analyze the genetic variability, heritability, genetic advance, correlation, path analysis and genetic divergence for 12 quantitative traits. All the 45 genotypes were grown in Randomized Block Design (RBD) with three replications. The observations were recorded on three randomly selected plants from each genotype in each replication for the twelve characters viz. days to 50% flowering, seed filling period, days to maturity, length of main shoot, number of pods on main shoot, number of primary branches per plant, number of secondary branches per plant, plant height, number of seeds per pod, grain yield per plant, test weight and oil content. All the genotypes exhibited highly significant difference for all the traits under study. The high genotypic coefficient of variation (GCV) and phenotypic coefficient of variation (PCV) was observed for number of secondary branches per plant, grain yield per plant and number of primary branches per plant. High heritability coupled with high genetic advance observed for number of secondary branches per plant, grain yield per plant, number of primary branches per plant, length of main shoot, plant height, number of pods on main shoot, days to 50% flowering, test weight and number of seeds per pod. Hence direct selection of genotypes can be done through these characters for further improvement of genotypes of Indian mustard. In general, the genotypic correlation coefficient values were higher than the phenotypic values. Grain yield per plant had highly significant positive correlation with plant height, number of secondary branches per plant, length of main shoot, number of pods on main shoot, number of primary branches per plant and days to 50% flowering at both genotypic and phenotypic level, such association was noticed indicating less influence of environment on association. Hence, improvement of grain yield per plant can be achieved by improvement of these characters. Among the various traits studied, plant height, number of secondary branches per plant and number of seeds per pod had high positive direct effect at both genotypic and phenotypic levels. This indicated that these characters are most contributing towards grain yield per plant which can be easily improved by selection. Five clusters were formed by D2 analysis using 12 quantitative traits. The clustering pattern is suggestive of the fact that geographic diversity is not efficient index of genetic diversity. Out of the five clusters, cluster IV was found as a largest cluster with a total number of 14 genotypes under this cluster followed by cluster V with 11 genotypes, cluster III have eight genotypes, cluster II have 7 genotypes and 5 genotypes in cluster I. The maximum intra cluster distance was recorded in cluster III and lowest intra cluster distance was recorded for cluster IV. The maximum inter cluster distance was revealed between cluster II and III and minimum inter cluster distance was recorded between cluster IV and V. Nine primers amplified a total of 20 alleles, with an average of 2.2 alleles per primer. Each locus contained a maximum of four alleles and a minimum of one allele (BG50) (BG1). Primer BG109 had the greatest Polymorphic Information Content (PIC) value of 0.95, while primer BG12 had the lowest at 0.6. The average PIC value of all polymorphic primers was 0.66. The average resolving power (RP) is 1.856, with a minimum of 0.05 (BG109) and a maximum of 0.54 (BG50), followed by BG45 (0.53), BG92 (0.42), and BG1 (0.42). The range of similarity coefficients was found between 0.3 to 1. Based on Jaccard’s coefficient of similarity values, among all combinations, the smallest GS value of 0.3 was observed between RH749 and KMR-15-1 which appears to be most distantly related the maximum similarity (1) was reported between 18 genotypes. By conducting D² analysis as well as molecular profiling of genotypes using SSR markers, there was sufficient diversity among the genotypes that was used for study. The genotypes which exhibited low diversity at phenotypic level, also exhibited higher diversity at molecular level. For instance, the genotypes KMR-15-2, KMR-15-1 and KMR-17-4 were grouped together in cluster IV, indicating morphological similarity among themselves. Whereas, same genotypes were present in different clusters at molecular level. Many genotypes which were distributed in different clusters at morphological level were grouped into the same clusters at molecular level indicating higher degree of genetic similarity at molecular level.
(Dr. Mukesh Kumar) (Anjali)
Advisor Author