The current study was carried out by performing half diallel analysis on 28 treatments [7 genotypes (KMR(E)18-2, TM188, KMR(E)18-1, KMR(E)16-1, KMR(E)17-2, KMR(E)16-2 (Surekha), KMR(E)17-1] and their 21 crosses in order to conduct a study on Components of Genetic variance of metric traits contributing to seed yield in Indian Mustard [Brassica juncea (L.) Czern. and Coss.]. Twelve quantitative characters were used to record the observations. With the exception of seed yield per plant (g), genetic analysis showed that both the additive and dominance components were significant for all the traits. However, for all the traits with the exception of days to maturity and length of main raceme (cm), the dominance component values were found to be higher than the additive component values. The estimates of the average degree of dominance showed the presence of over-dominance for all features except days to maturity and the length of the main raceme (in cm) which showed presence of partial dominance. The estimates of H2/4H1 showed a symmetrical distribution of positive and negative genes in the parents for days to maturity, plant height, and length of main raceme, whereas the distribution of other characters was asymmetrical. For nearly every attribute, the values of component KD/KR showed an unequal frequency of dominant and recessive genes, with a larger frequency of recessive genes, and the values of h2/H2 showed that more than one gene groups were in charge of governing all characters under investigation

Brassica juncea, Indian Mustard, Quantitative traits, Genetic Variance, Diallel Mating

For all the characters under study except for days to maturity and length of main raceme the magnitude of dominance components (H1&H2) was higher than the additive component (D) indicating the predominance of dominant gene action for all the traits except for the two aforesaid traits and that there is predominance of non- additive gene action for all traits except for days to maturity & length of main raceme. The predominance of non-additive gene action for plant height and number of branches per plant was also supported by Shrimali et al. (2017). The F component was found to be negative for four of the characters days to maturity, plant height, length of main raceme, total siliquae per plant indicating higher proportion of recessive genes than dominant in the parents. The values of ratio (H1/D)1/2 were found to be more than unity for all the traits indicating over dominance except for days to maturity and length of main raceme where it was less than unity. Over dominance for yield contributing traits were also reported by Thakral et al. (2000); Arifullah et al. (2012). The values of H2/4H1 revealed that there was symmetrical distribution of positive and negative genes in the parents for the traits days to maturity, plant height and length of main raceme, while other characters showed asymmetrical distribution. The equal distribution of positive and negative genes in the parents enables the breeder in selecting specific desirable traits without sacrificing any other desirable trait. The values of component KD/KR indicated unequal frequency of dominant and recessive genes with higher frequency of recessive genes for all the traits except for number of secondary branches per plant and number of siliquae in main raceme. The knowledge of number of genes/group of genes responsible for particular traits is important for the genetic progress through selection in the present study, the values of h2/H2 indicated that more than one gene group were responsible for governance of all the characters under study

Shivangi Gupta, Mahak Singh, Utkarsh Tiwari, G. Shiva Kumar and Saloni Singh (2024). Studies on Genetic Components for Seed Yield in Indian Mustard [Brassica juncea (L.) Czern. and Coss.]. Biological Forum – An International Journal, 16(6): 169-172.