黄瓜白粉病抗性遗传模型分析

Analysis of inheritance model of cucumber powdery mildew resistance

该研究以高感白粉病黄瓜品种D8和高抗白粉病黄瓜品种JIN5-508杂交后自交及回交所获得的6个群体(P1、P2、F1、BC1、BC2和F2)为材料,运用数量性状遗传模型分析方法(主基因+多基因混合遗传模型)对黄瓜白粉病抗性进行遗传分析。结果表明:黄瓜白粉病抗性遗传适合E-1模型,即2对加性-显性-上位性主基因+加性-显性多基因混合遗传模型,其中第1对基因呈负向部分显性,第2对基因呈负向超显性,且第2对基因显性程度显著高于第1对基因;抗白粉病主基因的遗传率在BC1、BC2和F23个世代分别为84.36%、80.08%和90.87%,其中以F2的主基因遗传率最高,BC2的主基因遗传率最低;多基因的遗传率BC2最低,其次为F2,BC1最高,分别为5.04%、6.25%、10.06%;BC1、BC2和F2世代的主基因遗传率都大于相应世代的多基因遗传率,黄瓜白粉病性状由主基因和多基因的共同作用决定,其中以主基因遗传为主。

Six generations of P1,P2,F1,BC1,BC2,and F2 derived from the cross of D8（susceptible to powdery mildew） and JIN5-508（resistant） of cucumber were employed to analyze the inheritance of powdery mildew resistance in cucumber by the model of major gene plus polygenic inheritance.Results indicated that the heredity of powdery mildew resistance in cucumber could be explained by two additive-dominance-epistasis major genes and additive-dominance polygene model（E-1 model）.The first pair of genes showed negative partial dominance,and the second,negative superdominance.The major genes＇ heritabilities of powdery mildew resistances in BC1,BC2 and F2 generations were 84.36%,80.08% and 90.87%,respectively.The heritability of polygenes was the lowest in BC2,and the highest in BC1.The inheritance of cucumber powdery mildew resistance was determined by both major genes and polygenes,among which,major genes exhibited the dominant effects.