Genetic analysis of erucic acid in brassica napus l. using mixed major gene and polygene inheritance model

Chinese. 【目的】芥酸含量是油菜非常重要的品质性状，研究芥酸含量的遗传模式为低芥酸和高芥酸育种提供指导。【方法】应用多世代联合分析数量性状主基因和多基因混合遗传的统计方法,分析了甘蓝型油菜组合1141B×垦C1的5个世代――亲本P1,P2,F1,F2和F2：3家系材料芥酸含量的遗传效应。【结果】分离世代F2及F2：3家系芥酸含量次数分布均呈混合的正态分布，符合主基因＋多基因的遗传特征；E-1模型为芥酸含量的最适合性模型，即芥酸含量遗传是由2对加-显-上位性主基因＋加-显多基因控制的。2对主基因加性效应值da、db分别为-16.26和-2.83，表明亲本1141B中主基因位点上的等位基因降低芥酸含量，而亲本垦C1中的等位基因增加芥酸含量。显性效应值ha、hb分别为10.93和-4.71，第一对主基因加性效应值和显性效应绝对值均高于第二对主基因显性效应值。因此，2对主基因控制芥酸含量，第一对主基因控制的芥酸含量高于第二对主基因。该组合2对主基因间互作效应明显，加性与加性效应互作值（i）为-1.21，显性与显性互作值（l）为-3.27。第一对主基因的加性效应与第二对主基因的显性效应互作值（jab）为5.70，第二对主基因的加性效应与第一对主基因的显性效应互作值（jba）为-7.25。其芥酸含量还受多基因控制，多基因加性效应（[a]）值为-0.08，多基因显性效应（[d]）值为2.32；F2的主基因遗传力和多基因遗传力分别为50.00%和16.62%；F2：3的主基因遗传力和多基因遗传力分别为89.70%和6.01%。【结论】芥酸含量是由2对加-显-上位性主基因＋加-显多基因控制的，第一对主基因控制的芥酸含量高于第二对主基因。低芥酸和高芥酸育种中在F2：3家系进行选择效率较高。

English. [ Objective ] Erucic acid is an important quantitative trait of rapeseed. Genetic analysis of erucic acid will provide a very important guidance for breeding of low and high erucic acid rapeseed. [Method] The joint segregation analysis method of mixed major gene plus polygene genetic model was used to study the inheritance of erucic acid in Brassica napus L. Five populations from each of the crosses （1141B × Ken C1） were investigated. The five populations were the parents P1, P2, F1, F2 and F2：3 （derived from F2） families. [Result] The frequency distributions of erucic acid in F2 and F2：3 family populations showed the characteristics of mixture normal distribution, which indicated that inheritance of erucic acid followed the major gene plus polygene model. Results showed that genetic model E-1 was the most fitted genetic model for the trait. In another word, erucic acid in oilseed rape was controlled by two major genes with additive-dominance-epistatic effects plus polygenes with additive-dominance effects. The estimated additive effects of the two major genes, da and db were - 16.26 and -2.83, respectively. It indicates that loci of the allele in parent 1141B decrease the erucic acid content, in parent Ken C1 increase it. The dominant effects of the two major genes, ha and hb were 10.93 and -4.71, respectively. The additive and dominance effects of the two major genes were much higher than that of the second one. Therefore, the contribution to erucic acid of the first major gene is much higher than the second one. There is a significant interaction between the two major genes. The interaction effect of the first major gene＇s additive effect and the second major gene additive effect （i） was -1.21. The interaction effect of the first major gene＇s dominant effect and the second major gene dominant effect （1） was -3.27. The interaction effect of the first major gene＇s additive effect and the second major gene dominant effect （jab） was -5.70. The interaction effect of the second major gene＇s additive effect and the first major gene dominant effect （jba） was -7.25. Erucic acid content was also controlled by polygene. The additive and dominant effect of the polygene were -0.08 and 2.32, respectively. The major gene and polygene heritabilities in F2 were 50.00% and 16.62%, respectively, and in F2：3 were 89.70% and 6.01%, respectively. [Conclusion] Inheritance of erucic acid followed by two major genes with additive- dominance-epistatic effects plus polygenes with additive-dominance effects. And the contribution to erucic acid of the first major gene is much higher than the second one. It would have a high efficiency when selecting in F2：3 families for high and low erotic acid in breeding.