利用主基因+多基因混合遗传分析解析陆地棉铃重与铃壳率杂种优势的遗传基础

Genetic Foundation of Heterosis for Boll Weight and Shell Ratio in Upland Cotton(Gossypium hirsutum L.) Using Mixed Major-Genes Plus Polygenes Inheritance Analysis

为明确棉花杂种F1铃重超亲优势的遗传基础,利用数量性状主基因+多基因混合遗传P1、P2、F1和F2群体联合分析方法,分析了铃重有超亲优势的3个组合L178×L029(Ⅰ)、L178×L057(Ⅱ)与L029×GP72(Ⅲ)的铃重与铃壳率。结果表明:3个组合F1铃重的超亲优势和铃壳率的负向中亲优势表现稳定。组合Ⅰ和ⅡF2群体的铃重与铃壳率呈极显著负相关。铃重和铃壳率均呈2对主基因+多基因遗传,但主基因作用方式在组合间有所不同。铃重超亲优势主要来自多基因显性效应,而组合Ⅲ的主基因显性×显性互作对铃重的超亲优势也有很大作用。组合Ⅰ和Ⅲ铃壳率的负向中亲优势主要来自于主基因显性效应,组合Ⅱ铃壳率的负向优势主要来自于多基因显性效应。因此,改良铃重和铃壳率时可通过轮回选择或修饰回交聚集增效基因来实现。

To understand the genetic foundation of over-parent heterosis for boll weight in upland cotton（Gossypium hirsutum L.）, we used mixed major-genes plus polygenes inheritance analysis of P1, F1, P2, and F2 populations to investigate inheritance of boll weight and boll shell ratio in three over-parent heterosis crosses L178 × L029（Ⅰ）, L178 × L057（Ⅱ）, and L029 × GP72（Ⅲ） in 2013. The results showed that over-parent heterosis for boll weight and negative mid-parent heterosis for boll shell ratio were stable in the three crosses. Boll weight was significantly and negatively correlated with boll shell ratio in the F2 populations of crosses Ⅰ and Ⅱ. The two traits were controlled by two major genes plus polygenes, although the action modes for the major genes varied across crosses. The over-parent heterosis of boll weight was mainly controlled by the dominance effect of polygenes, although significant dominance-by-dominance interactions for major genes was observed in cross Ⅲ. The negative mid-parent heterosis of boll shell ratio was found to be associated with the dominance effect of major genes in crosses Ⅰ and Ⅲ,and with the dominance effect of polygenes in cross Ⅱ. Therefore, recurrent selection and modified backcrossing can be used to pyramid cotton novel alleles to improve boll weight and boll shell ratio.