玉米低钾耐性性状的主基因+多基因遗传分析

Genetic Analysis of Tolerance to Low-potassium Stress in Maize Using Mixed Model of Major Gene Plus Polygene

应用植物数量性状主基因+多基因混合遗传模型多世代联合分析方法,以玉米缺钾症状叶片数为指标,对1个耐低钾玉米自交系T和2个低钾敏感玉米自交系S1和S2配制成的2个组合的P1、P2、F1、B1、B2和F2世代进行遗传分析,研究明确玉米耐低钾性状的遗传机制。结果表明,玉米低钾耐性遗传在2个组合中都由1对加性+加性-显性多基因控制;主基因遗传率(F2)平均为60.43%,多基因遗传率(F2)平均为15.35%;T×S1组合的遗传变异占表型变异值为80.20%,T×S2组合的遗传变异占表型变异值为71.35%,表明耐低钾性状以主基因遗传为主。育种应用上可以在低世代进行这一目标性状的选择。

The present study was aimed to estimate the genetic model and genetic parameters of maize tolerance to low-potassium using the number of leaf with low potassium symptom in six generations （P1, P2, F1, B1, B2 and F2） derived from two crosses of T （tolerance to low-potassium stress） × S1 （sensitivity to low-potassium stress） and T× S2 in maize. The results showed that tolerance to low-potassium stress in maize was dominated by one major gene with additive effects plus poly-genes with additive-dominance effects （D-2 model） in two cross. The additive effects of two 2 major genes in two crosses were more powerful than poly-genes. On average, hereditability of major genes （hmg^2） was 2 60.43% in F2 population, and that of poly-genes （h g） in Fz population was 15.35%. It indicated that the tolerance to low-potassium stress in maize was dominated by major genes. In addition, the genetic variance accounted for 80.20% and 71.35% of the phenotypic variance in each population respectively, indicating higher hereditability of major genes can be favorable to an efficient selection in early generation of tolerance to low-potassium stress breeding.