Gene Action and Combining Ability of Important Agronomic Traits in Rapeseed (Brassica napus L.)

Inheritance of yield and its contributing characters in rapeseed (Brassica napus L.) was studied in a 8×8 diallel cross through Griffing and Jinks-Hayman analyses. Both general combining ability (GCA) and specific combining ability (SCA) were highly significant for seed yield, seed weight and branches per plant, while only GCA for seeds per pod and oil content and only SCA for pods per plant and days to maturity were significant. Both Griffing and Jinks-Hayman analyses showed that seed yield, seed weight and branches per plant were genetically controlled by both additive and non-additive gene actions. Overdominance gene action was observed for seed yield and its increasing was controlled by dominant alleles. Additive gene action was important for seeds per pod and oil content, while pods per plant and days to maturity were governed by non-additive gene action. Relatively high narrow-sense heritabilities were estimated for seeds per pod and seed weight indicating that a considerable selection response is expected for these characters in breeding programs. The results suggested that RGS003 with the highest GCA for seed yield could be used as a tester in topcross trials and 19H×Option500 with the highest SCA and heterobeltiosis could be applied in hybrid breeding.