标准切花菊分枝性状的杂种优势和混合遗传分析

为明确标准切花菊分枝性状的杂种优势及主基因效应,以标准切花菊QD3-71× 精之一世(组合Ⅰ)的97个杂交后代和秦淮春雪×神马(组合Ⅱ)的147个杂交后代作为遗传群体,对其总侧芽数、上部一级分枝数、一级分枝粗、一级分枝角度、一级分枝长度、总侧芽数/叶节数6个相关分枝性状进行杂种优势分析和主基因+多基因混合遗传分析。结果表明,两组合F₁群体各分枝性状呈连续分布,变异系数为10.23%~39.92%;两组合各分枝性状存在不同程度的中亲优势,超亲分离现象广泛存在,总侧芽数、上部一级分枝数在两组合中均存在偏母性遗传效应,一级分枝长度在组合Ⅰ中存在正向超亲优势。混合遗传分析表明,在组合Ⅰ中,总侧芽数/叶节数符合表现为由两对加性效应主基因控制的B-3模型,主基因遗传率为98.84%;在组合Ⅱ中,上部一级分枝数符合表现为由两对加-显-上效应主基因控制的B-1模型,一级分枝长度和总侧芽数/叶节数符合表现为由一对加-显效应主基因控制的A-1模型,主基因遗传率分别为93.04%、36.84%和52.11%;总侧芽数在两个组合中均符合表现为由一对加-显效应主基因控制的A-1模型,主基因遗传率分别为57.39%和46.73%;一级分枝粗、一级分枝角度在两个组合中均符合A-0模型,无主基因控制。本研究表明标准切花菊分枝性状的主基因效应在不同遗传背景中差异较大,这些主基因效应的发现为QTL定位研究提供了参考,对标准切花菊的株型育种具有重要价值。

Heterosis and Mixed Inheritance Analysis of Branching Traits in Standard Cut-Chrysanthemum

To understand heterosis and major gene effect, inheritance and major gene plus polygene mixed genetic model analysis were carried out for six branching traits of standard cut-chrysanthemum based on 97 F₁ population of cross combination Ⅰ derived from QD3-71 (female parent) and Sei No Issei (male parent), and 147 F₁ population of cross combination Ⅱ derived from Qinhuaichunxue (female parent) and Jinba (male parent). i.e. total number of lateral buds, number of upper primary branches, primary branch diameter, primary branch angle, primary branch length and total number of lateral buds/number of leaf nodes. The results indicated that the six branching traits were continuously distributed, with coefficient of variation (CV) ranging from 10.23% to 39.92%. Branching traits of the two combinations had varying degrees of mid-parent heterosis, and the phenomenon of over-parent individuals widely existed. Partial maternal inheritance was observed for total number of lateral buds and number of upper primary branches in the two combinations. In addition, primary branch length of cross combination Ⅰ showed over-parent heterosis. The mixed inheritance analysis indicated that total number of lateral buds/number of leaf nodes in cross combination Ⅰ was fitting B-3 model with additive effect of two pairs of major gene, and the heritability of major gene was 98.84%. In cross combination Ⅱ, number of upper primary branches was fitting B-1 model with additive-dominant-epistatic effect of two pairs of major gene, and the heritability of major gene was 93.04%. Meanwhile, primary branch length and total number of lateral buds/number of leaf nodes in cross combination Ⅱ were fitting A-1 model with additive-dominant effect of one pair of major gene, and the heritability of major gene was 36.84% and 52.11%, respectively. However, total number of lateral buds was fitting A-1 model with additive-dominant effect of one pair of major gene in two combinations, and the heritability of major gene was 57.39% and 46.73%, respectively. Primary branch diameter and primary branch angle were fitting A-0 model in two combinations with no major gene detected. The results indicated that the major gene effects of standard cut-chrysanthemum branching traits were different in different genetic backgrounds, but the discovery of these major gene effects provided references for QTL mapping research and was of great value in standard cut-chrysanthemum breeding of plant architecture.