源于陕A群、陕B群玉米自交系在不同密度条件下配合力分析

Combining Ability of Maize Inbred Lines from Shaan A Group and Shaan B Group under Different Density Conditions

采用NC-II遗传设计,以郑58、昌7-2为测验种,与17份高密度条件下筛选的玉米自交系组配成34份杂交组合,2014—2015年分别于陕西杨凌、长武、榆林进行3种密度(45 000、67 500和90 000株hm–2)配合力分析试验。采用PROC VARCOMP分析不同密度条件下产量及耐密性相关性状的遗传效应,采用频率直方分布图研究不同密度条件下产量及耐密性相关性状一般配合力(GCA)平均数的变化规律,利用AMMI评价玉米自交系与杂交组合的稳定性。结果表明,产量、倒伏率、茎秆强度主要受加性遗传效应控制,空秆率主要受非加性遗传效应控制。加性遗传效应对产量及耐密性相关性状的贡献率随种植密度的增加呈上升趋势。玉米自交系产量、空秆率、倒伏率、茎秆强度的一般配合力频率均属于正态分布,随着种植密度的增加,产量GCA的平均值提高了0.28,空秆率GCA平均值降低了0.21,倒伏率GCA平均值降低了0.03,茎秆强度GCA平均值增加了0.02。玉米杂交组合产量与玉米自交系产量GCA密切相关(r=0.877**,r=0.811**,r=0.672**)。随着种植密度的增加,表现稳定的玉米自交系及杂交组合的数量呈上升趋势。因此,强化逆境选择压力,实施高密度选择策略,是增强玉米自交系耐密性和抗倒性,提升一般配合力,实现产量增益的有效措施。

The objective of this study was to investigate the effectiveness of high-density breeding strategy through analyzing genetic components and general combining ability(GCA)effects under different planting densities.Seventeen maize inbred lines selected under high density were test-crossed with two testers(Zheng58,Chang7-2)in the North Carolina Design II.Thirty-four crosses were evaluated under different density conditions(45000,67500,and90000plants ha-1)in2014and2015at Yangling,Changwu and Yulin in Shaanxi province.The genetic variance components for grain yield and other traits were estimated using PROC VARCOMP method.Frequency distribution was used to analyze the response of GCA for grain yield and other traits under different densities.The stability of maize inbred lines and crosses was evaluated based on AMMI model.The grain yield,stalk lodging rate and rind penetration strength were mostly controlled by additive gene action,while the inheritance of sterile plant rate controlled by non-additive gene action.Also,the contribution of additive gene action to total variance increased with increasing planting density.The average of general combining ability for grain yield,sterile plant rate,stalk lodging rate and rind penetration strength increased by0.28,?0.21,?0.03,and0.02,respectively,from low density to high density.The correlations between GCA of the inbred lines and their crosses were significant(r=0.877**,r=0.811**,r=0.672**)under different density.As the density increased,the number of stable maize inbred lines and crosses increased.These results indicate that increasing plant density to improve GCA for grain yield and other traits of inbred lines is an effective strategy to enhance tolerance to high plant density and yield stability.