甜瓜果实糖含量的主基因+多基因遗传分析

Genetic analysis of fruit sugar content in melon(Cucumis melo L.) based on a mixed model of major genes and polygenes

以‘花皮菜瓜’(低糖越瓜自交系)和‘XLH’(高糖厚皮甜瓜自交系)为亲本构建P1、P2、F1、F2、B1、B2 6个世代遗传群体,利用高效液相色谱法测定该6个世代遗传群体甜瓜果实糖含量,采用植物数量性状主基因+多基因混合遗传模型分析方法对甜瓜果实葡萄糖、果糖、蔗糖及总糖含量进行联合遗传分析。结果表明:甜瓜果实果糖含量受2对加性-显性-上位性主基因+加性-显性-上位性多基因控制(E-0模型),葡萄糖、蔗糖和总糖含量受2对加性-显性-上位性主基因+加性-显性多基因控制(E-1模型);果糖、葡萄糖、蔗糖和总糖含量均为2对主基因+多基因遗传模型,主基因以负向增效为主,遗传主基因间普遍存在互作效应,控制果糖、葡萄糖和总糖含量的2对主基因间显性×显性互作效应最强,而控制蔗糖含量的主基因间显性×加性互作效应最强,控制蔗糖和总糖含量的多基因负向加性效应较明显;控制果糖、葡萄糖、蔗糖和总糖含量的主基因在F2中的遗传率分别为85.7%、86.2%、92.7%和85.0%,且受环境影响较小。因此,在甜瓜育种过程中对糖组分含量性状的定向选择宜在早世代进行。

Sugar contents of six generation populations(P1,P2,F1,F2,B1 and B2)derived from the cross between low sugar content inbred line‘Huapicaigua’(Cucumis melo var.conmmon Makino)and high sugar content inbred line‘XLH’(Cucumis melo var.saccharinus Naud.)were determined by high performance liquid chromatography(HPLC)method.Fruit sugar related traits in melon were analyzed using the joint segregation analysis method of a mixed major gene plus polygene genetic model.The results showed that the genetic model E-0,incorporating two pairs of additive-dominance-epitasis major genes plus an additive-dominance-epitasis polygene,was the best-fitting genetic model for fruit fructose content;and the genetic model E-1,incorporating two pairs of additive-dominance-epistasis major genes plus an additive-dominant polygene,was the optimal genetic model for fruit glucose,sucrose and total sugar contents.The fructose,glucose,sucrose,and total sugar contents were all controlled by two pairs of major genes and polygenes;the additive effect of major genes was mainly negative,and the interaction between the major genes was in common.Among them,the dominant and dominant interaction effect of the major genes for fructose,glucose and total sugar contents were the strongest,while the dominant and additive interaction effect of the major genes for sucrose content was the strongest.The negative additive effect of polygenes for sucrose and total sugar contents was relatively obvious.The heritabilities of major genes in the F2 populations conferring the fructose,glucose,sucrose and total sugar contents were 85.7%,86.2%,92.7%and 85.0%,respectively;and the environment showed very little effect for fruit sugar content.Thus,in melon breeding,selection for high sugar content in early generation melon is desirable.