Genetic analysis of a specially long pod character in artificially resythesized Brassica napus L

Two hybrid combinations were made with a resynthesized specially-long pod line in H218 Brassica napus L.,namely H218×Zhongyou 821, H218×MSP334 and their six generations F1, F2, backcrosses B1 and B2 and their parents P1 and P2 were used to study the inheritance of 3 pod related traits, namely the full pod length, the pod body length and the pod beak length. The results were the followings: the three traits in the F2 population of the two combinations had a continuous normal distribution, indicating that these traits were quantitative in nature and controlled by polygenes. The broad-sense heritabilities of the full pod length, pod body length and pod beak length of the two combinations were 65.89% — 70.77%, 60.14% — 63.38% and 26.36% — 46.44%, respectively. The narrow-sense heritabilities were 44.01%—46.78%, 46.89%—47.38% and 18.08%—37.87%, respectively. The results from the two combinations consistently showed that full pod length, pod body length and pod beak length were controlled by 5, 6 and 2 genes respectively. The preliminary study on the gene effect demonstrated that the three traits in the two combinations all fit the additive-dominant model and the epistatic effect was significant. The additive effects and the dominant effects of the three traits in the two combinations were both significant. Of the full pod length and the pod body length, the dominant effect was more significant than the additive effect; and it is the same case for the pod beak length.