黄瓜叶面积的主+多基因混合遗传模型分析

Genetic Analysis of Leaf Size Using Mixed Major-gene Plus Polygene Inheritance Model in Cucumis sativus

以叶面积差异极显著的黄瓜小叶自交系‘SJ57-h’和大叶自交‘系SJ11-1’配制成的P1、P2、F1、F2、B1、B2等6个世代为材料,应用主基因+多基因混合遗传模型,结合春秋两季的试验数据,研究了叶面积的遗传规律。结果表明:春季和秋季叶面积的最适遗传模型均为E-0模型,即叶面积由两对加性—显性—上位性主基因+加性—显性—上位性多基因控制,且均具有大叶亲本优势,即叶面积大小更趋近于大叶亲本。春季,B1、B2和F2分离世代的主基因遗传力分别为75.1%、26.59%和61.19%,多基因遗传力分别为0.36%、55.41%和21.39%,环境方差占表型方差的比例分别为25.03%、73.79%和39.01%;秋季B1、B2和F2分离世代的主基因遗传力分别为80.16%、34.82%和86.59%,多基因遗传力分别为0、49.18%和0,环境方差占表型方差的比例分别为20.43%、65.48%和13.51%,表明黄瓜叶面积主要受两对主基因控制,B2世代受环境影响较大,B1、F2世代主基因选择率较高,B2世代多基因选择率较高,应该在早期世代进行选择。

To investigate how cucumber leaf size is geneticially determined,two parents with signicantly different leaf size,namely‘SJ57-h'(small leaf,‘P1'hereinafter)and‘SJ11-1'(big leaf,‘P2'hereinafter),were used to generate F1,B1,B2 and F2 populations for joint analysis,using mixed major gene plus polygene inheritance model in different seasons. The results showed that the leaf size was controlled by two additive-dominant-epitasis major genes plus additive-dominant-epitasis polygenes(E-0 model). Leaf size was closer to P2(big size). In spring,the major gene heritability of B1,B2 and F2 were estimated to be 75.1%,26.59% and 61.19%,respectively,with the heritability of polygene as 0.36%,55.41% and 21.39%,respectively. The variance of the environment accounted for 25.03%,73.79%,39.01% of the phenotypic variation of three generations,respectively. In autumn,the major gene heritability of B1,B2 and F2 were estimated as 80.16%,34.82%,86.59%,with the heritability of polygene being 0,49.18% and 0,respectively,and the variance of the environment accounted for 20.43%,65.48%,13.51% of the phenotypic variation,respectively. It indicated that cucumber leaf size was dominated by major genes while environment factors also play a great role,espcially on the B2 generation. In practice,high hereditability of major genes is favorable to an efficient selection in early generation of F2 and B1 for suitable leaf size in cucumber breeding.