Mondal, Hossain AliTingnunniang2023-04-262023-04-262022-12https://krishikosh.egranth.ac.in/handle/1/5810196711Indian mustard (Brassica juncea L. Czern and Coss) is an important Rabi season oilseed crop belonging to the family Brassicaceae and is the most widely grown oilseed crop in Meghalaya. The performance of Indian mustard is drastically affected under acidic condition of north-eastern India while it perform better under neutral pH as well as at moderate saline soil. Mustard crop improvement specially Indian mustard is challenging because of the difficulty of the inheritance of yield and its characteristics. Since yield is a quantitative characteristic and the culmination of a series of contributing characters, its response to selection is weak. For a breeding effort intended to create stable varieties with high yields, it is important to determine the type and extent of genetic variation as well as genetic gain of the trait. Therefore, the present study was conducted with objectives to identify promising genotypes for yield attributing traits and to estimate several genetic variability parameters of yield. Ninety-five B. juncea accessions collected from different sources were evaluated in augmented block design along with four checks (Varuna, Kranti, Rohini and NRCHB- 101). It was observed that analysis of variance showed significant difference among genotypes for all the traits except for days to 80% flower bud formation. Among all the characters which were found to have high heritability (>60%), days to first flowering (DTFF) (94.01%), days to maturity (DTM) (92.53%) and plant height (PH) (88.74%) had the highest value. It was observed that number of siliquae per plant (NSQPP) showed highest genetic advance and heritability followed by plant height (PH), biological yield (BY), days to 100% flowering and dry weight (DW). From correlation study of agromorphological traits, NSQPP, BY, DW, Harvest Index (HI) and number of seeds per siliqua (NSPS) and number of secondary branches per plant (NSB) were found to be highly correlated with seed yield (SY). Based on the adjusted means obtained from augmented design analysis, the maximum yield per plant was recorded in the genotypes, Vardan (13.8g), followed by RH-0923 (13.33g), RW-46-3 (12.35g), RLJEB- 84 (11.78g), KMR-53-3 (11.69g) and DRMR-4001 (11.55g). Characters such as, BY, HI, and NSQPP had exhibited a high positive direct effect on seed yield per plant. The highest positive indirect effect on seed yield per plant was exhibited by DW through BY. The diversity analysis based on agglomerative clustering of Ward’s method grouped the current set of genotypes under study into 5 clusters. Cluster V was found to have highest mean values for seed yield and yield attributing traits as well as they are early maturing. All the clusters' inter-cluster distances were greater than their intra-cluster distances suggesting the presence of wider genetic diversity among genotypes in various groupings. Highest inter-cluster distance (D2) was found between cluster III and V (9.48). Days to 100% flowering, days to 50% flowering and days to first germination were the traits which contributed maximum in first principal component (PC1). Vardan, RL-JEB-84, DRMR-4001, CS-2009-332, RH-0923, Rohini (SC), RH-119, PBR-210, KMR-53-3, RW-46-3, RGN-229, CS-2009-347, CS-2004-114,CS-2013-10, Vaibhav were the genotypes present at extreme points of PCA individuals biplot indicating that these lines were expected to have more genetic diversity and genetic variability for the yield contributing traits. Genotypes such as, Vardan, RH-0923, RL-JEB-84, DRMR-4001, KMR-53-3 and RW-46-3 were high yielding among all the genotypes. Whereas from correlation and path coefficient analysis, revealed that biological yield, number of siliquae per plant, harvest index and number of secondary branches per plant were the traits showing high positive correlation as well as positive direct effect with seed yield. Therefore, these traits can be emphasized during selection for yield improvement of the crop.EnglishThesis