巢式杂交分离群体的花生籽仁性状的主基因+多基因混合遗传模型分析

【目的】花生籽仁性状是花生产量的重要构成因素。通过对花生巢式杂交群体的籽仁性状开展遗传模式研究,为进一步利用其衍生巢式关联作图群体开展花生籽仁性状QTL定位及开发分子标记辅助花生高产育种提供材料基础及理论依据。【方法】以豫花15为共同亲本,远杂9102、中花6号、粤油20、伏花生和NC94022为基础亲本,组配远杂9102×豫花15、中花6号×豫花15、豫花15×粤油20、豫花15×伏花生和豫花15×NC94022共5个组合的巢式杂交群体,通过F₂单株收获共获得1 812个F_2:3家系,将籽仁性状分解为籽仁长、宽、长宽比、表面积、表面周长及单仁重等6个性状,分析各个性状之间的拟合度、相关性,利用数量性状的主基因加多基因混合遗传模型分别对其进行遗传模型分析与遗传参数估计,确定控制各个性状的基因数目、遗传效应值及遗传力。【结果】花生巢式杂交分离群体中,籽仁性状变异类型丰富,籽仁6个性状在不同组合中均表现为超出双亲的正态分布;籽仁不同性状间存在一定相关性,籽仁长、籽仁表面积和表面周长三者之间呈显著相关,籽仁宽与籽仁长宽比呈负相关性,但相关性低;籽仁6个性状之间的相关性越大,拟合度也越高;不同组合的不同籽仁性状的遗传模型存在差异,在籽仁的6个性状中,籽仁表面积、表面周长在5个组合中均符合1MG-AM模型,籽仁宽、长宽比、单仁重均有4个组合符合1MG-AD模型,籽仁长有3个组合符合1MG-NCD模型,籽仁长、长宽比均有1个组合符合2MG-EAD模型,主基因遗传力3.80%—77.06%,不同群体中的基因效应值不同,表明多等位基因或非等位基因的不同遗传效应以及遗传背景的差异。【结论】花生巢式杂交群体的籽仁性状以多基因遗传效应为主,其遗传表现出不同的模式,表明该巢式杂交群体中不同组合籽仁性状的调控基因差异,为全面解析复杂籽仁性状的遗传机制提供了群体材料。

Genetic Analysis of Peanut Kernel Traits in a Nested-crossing Population by Major Gene Plus Polygenes Mixed Model

【Objective】Peanut kernel traits are important components of peanut yield. The genetic models of peanut kernel traits were analyzed in a peanut nested-crossing population to provide material and theoretical basis for further QTL mapping in the derived nested association mapping (NAM) population and for marker developing to assist breeding for high yield peanut varieties.【Method】The nested-crossing population containing five combinations of Yuanza 9102×Yuhua 15, Zhonghua 6×Yuhua 15, Yuhua 15×Yueyou 20, Yuhua 15×Fuhuasheng and Yuhua 15×NC94022 was constructed using Yuhua 15 as common parent and other five varieties as founder parents. A total of 1812 F_2:3 families were obtained by single plant harvesting in F₂, and the six kernel traits including kernel length, width, ratio of length to width, surface area, surface perimeter and average-kernel weight were measured for each family. The fitness and correlation between each pair of the traits were analyzed. The major gene plus polygene mixed genetic model of quantitative traits was tested and the genetic parameters, the number of control genes, the genetic effects and the heritability were estimated.【Result】 In the segregated populations of nested- crossing, the variation of kernel traits were extensive, and all the six traits showed normal distribution exceeding both parents in each of the combinations. There were significant correlations between each pair of the three traits including the kernel length surface area and surface perimeter. However, the correlation between kernel width and the ratio of length to width was low. The greater the correlations between each pair of the six traits, the higher the fitness. The genetic models of the kernel traits differed among the combinations. The genetic pattern of kernel surface area and kernel surface perimeter in all of the five combinations belonged to one major gene of additive-dominant model (1MG-AD), while that of the width, ratio of length to width and average kernel weight in four combinations also followed 1MG-AD pattern. The kernel length conformed to one major gene and negative completely dominant (1MG-NCD) model in three combinations, and the kernel length and ratio of length to width in one combination conformed to two major genes of equally dominant (2MG-EAD) model. The heritability of major genes was 3.80%-77.06% and the various implied the exist of multiple alleles or non-alleles in major genes as well as the minor genes in the backgrounds of different combinations.【Conclusion】Most of the kernel traits in the peanut nested-crossing population had polygenic genetic effects, and followed different genetic models. These results indicated that the genetic background of kernel traits differed in this nested-crossing population and the genetic materials will further benefit the comprehensive dissection of the genetic mechanism of complex kernel traits.