关键词: 花生, 巢式杂交群体, 巢式关联作图群体, 籽仁性状, 主基因+多基因遗传模型

Abstract:

【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.

Key words: peanut (Arachis hypogaea L.), nested-crossing population, nested association mapping (NAM), kernel traits, major gene plus polygene model