甘蓝型油菜分枝角度主基因+多基因混合遗传模型及遗传效应

分枝角度是油菜株型重要性状，是油菜品种高产及适合机械化收获理想株型的基本组成之一。为明确油菜分枝角度的遗传，本研究选用油菜分枝角度大的松散型材料6098B和分枝角度小的紧凑型材料Purler配制杂交组合，采用主基因+多基因混合遗传模型方法对该组合6世代(P₁、P₂、F₁、F₂、BCP₁和BCP₂)的分枝角度进行了遗传分析。结果表明，上部第一分枝(顶枝)和基部第一分枝(基枝)角度的最适合遗传模型均为D-0 (1对加性-显性主基因+加性-显性-上位性多基因)。顶枝角的主基因加性效应值为4.939º，显性效应值为–4.156º，主基因遗传率在BCP₁、BCP₂和F₂中分别是34.08%、1.40%和14.99%，多基因遗传率分别为24.43%、61.72%和63.98%；而基枝角的主基因加性效应值为2.217º，显性效应值为–1.941º，主基因遗传率在BCP₁、BCP₂和F₂中分别是7.86%、1.24%和4.84%，多基因遗传率分别为66.46%、58.49%和73.96%。结果发现油菜分枝角度明显存在主效基因，为油菜分枝角度的遗传改良奠定了基础。

Genetic Effects of Branch Angle Using Mixture Model of Major Gene Plus Polygene in Brassica napus L.

Branch angle is one of important plant architectural traits in rapeseed (Brassica napus), which is the basic requirement for high-density cultivation and mechanical harvesting. To reveal the genetic mechanism of branch angle in rapeseed, we produced six generations (P₁, P₂, F₁, F₂, BCP₁, and BCP₂) from a cross between loose-type 6098B and compact-type Purler to analyze genetic effects of branch angle in rapeseed by the mixed major gene plus polygene inheritance model. The branch angle showed a continuous normal distribution, where both the basal branch angle and the top branch angle were dominated by a pair of major gene with additive-dominant effects plus polygenes with additive-dominance-epistasis effects (D-0 model). The additive effect and dominant effect of major gene of the top branch angle were 4.939 and –4.156, the heritability in BCP₁, BCP₂ and F₂ was 34.08%, 1.40%, and 14.99%, respectively for the major gene, and 24.43%, 61.72%, and 63.98%, respectively for the polygenes. The additive effect and dominant effect of major gene of the basal branch angle were 2.217 and –1.941, the heritability in BCP₁, BCP₂ and F₂ was 7.86%, 1.24%, and 4.84%, respectively for the major gene, and 66.46%, 58.49%, and 73.96%, respectively for the polygenes. Results of this study found that the branch angle traits of 6098B×Purler is controlled by polygenes, but there is a major gene among them. The research may be useful for further understanding and genetic improvement of plant architecture in rapeseed.