Epistatic interactions for seed yield and component traits in Ethiopian mustard (Brassica carinata)

The present study was carried out to congregate information on nature of gene action for seed yield and other important characters in Ethiopian mustard (Brassica carinata A. Braun). The materials for the investigation comprised of 16 fixed mutant lines, three testers i.e. Jayanti, P_(4)2b and their F₁ (Jayanti × P_(4)2b) and resulting 48 TTC hybrids. These progenies and their parents were grown in randomized complete block design with three replications during rabi 2016–17 at the Experimental Farm of the Department of Genetics and Plant Breeding, CSK HPKV, Palampur (H.P.). Analysis of variance indicated the significance of mean squares due to genotypes for all the traits which revealed the presence of sufficient genetic variability in the existing material. Triple test cross analysis exhibited the presence of significant epistasis for all the traits except for plant height and harvest index. Further, partitioning of epistasis revealed the importance of ‘j + l’ (additive × dominance + dominance × dominance) type of epistasis for almost all the traits except for plant height and harvest index whereas, ‘i’ (additive × additive) type interactions were non-significant for all the traits except for days to 50 per cent flowering, number of secondary branches per plant, seeds per siliqua and oil content. The average degree of dominance (H/D)^1/2 was in the range of partial dominance for most of the traits except for seeds per siliquae, biological yield per plant and oil content indicating the relative importance of fixable type of gene action in their inheritance.