Quantitative Genetic Analysis of Silk Cut in Maize (Zea mays L.)

chinois. 分析玉米丝裂病发生的遗传机制，为选育抗丝裂病品种和高效改良感病材料提供理论依据和技术支持。运用六世代平均值分析法和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的方法，对普通玉米自交系R08与975-12杂交组合的P1、P2、F1、F2:3、B1:2和B2:2 6个世代群体的种子丝裂病进行分析。玉米丝裂病的遗传符合1对加性主基因+加性-显性多基因模型。在F2:3、B1:2和B2:2 3个家系世代，主基因方差分别为201.45，31.99和31.99；多基因方差依次为11.04、81.14和0.00。主基因加性效应值为11.31；多基因加性效应值为-4.47，显性效应值为10.85。主基因遗传率在F2:3和B1:2两个分离家系群体中为81.31%和21.56%，多基因遗传率为4.46%与54.68%。B2:2家系中未检测出多基因的存在。玉米丝裂病主要由加性主基因控制，在抗病育种中可在早代高强度选择，对感病自交系可采取回交转育的方法进行改良。

anglais. This study was conducted to provide theoretical bases for breeding silk cut resistance in maize (Zea mays L.). Six populations (P1, P2, F1, F2:3, B1:2 and B2:2) derived from the same cross of R08×975-12 were used to investigate the inheritance of silk cut resistance by using the traditional generation mean analysis and the mixed major gene and poly-gene inheritance model. Results indicated that silk cut in the cross R08×975-12 was controlled by one major gene with additive major gene effects plus polygene with additive-dominance effects (the D-2 model). Genetic variances of the major gene in F2:3, B1:2 and B2:2 populations were estimated as 201.45, 31.99 and 31.99, and those of polygene were 11.04, 81.14 and 0.00, respectively. The additive effects of major gene and polygene were estimated as 11.31 and -4.47, respectively, and the dominance effects of polygene was 10.85. Heritabilities of the identified major gene in F2:3 and B1:2 populations were estimated as 81.31% and 21.56%, while those of polygene were 4.46% and 54.68%, respectively. Silk cut in maize in the studied cross was controlled by one additive major gene, so during the breeding for silk cut resistant maize inbred lines, strong selection pressure can be applied in early generations and backcross breeding.