Speed approach for genetic analysis of quantitative traits in linseed (Linum usitatissimum L.) genotypes under sub temperate conditions of Western Himalayas using shuttle breeding

Gene action studies are important component to formalize the breeding programmes. In the present study, genetic components of variation for different traits were determined in one and half year using triple test cross approach along with shuttle breeding in linseed. Epistasis was observed significant for all studied traits. The [i] type epistasis was significant for days to 50%flowering, days to 75% maturity, secondary branches per plant, capsules per plant, 1000-seed weight and aerial biomass per plant. [j +1] type epistatic interactions were significant for all the traits except seed yield per plant. The additive (D) and dominance (H) component were significant for all the studied traits. This illustrated that both additive and dominance gene actions controlling all the traits but in higher order as epistasis is also present. The average degree of dominance indicated the preponderance of additive type of gene action for aerial biomass per plant, primary branches per plant, seed yield per plant, secondary branches per plant, capsules per plant, days to 50% flowering, harvest index, seeds per capsule, days to 75% maturity and technical height,whereas non-additive type of gene action was preponderant for plant height and 1000-seed weight. The additive gene effects were predominant as compared to dominance effects for almost all of the traits along with seed yield per plant. Under such genetic control in the expression of traits, early generation selection might be beneficial for the improvement of these traits. However, where both additive and dominance gene actions prevail, genetic disassortative mating followed by recurrent selection methodmight be suitable approach towards the genetic improvement of the traits.