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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。
Using NC-II genetic design, Zheng58 and Chang7-2 as test species, 34 hybrid combinations were obtained from 17 high-density maize inbred lines. Wuhan, Yulin three kinds of density (45 000, 67 500 and 90 000 hm-2) Combining ability test. PROC VARCOMP was used to analyze the genetic effects of yield and density-related traits under different densities. The frequency histogram was used to study the changes of the average GCA of yield and density-related traits under different densities. AMC Evaluation of the stability of maize inbred lines and cross combinations. The results showed that yield, lodging rate and stalk strength were mainly controlled by additive genetic effect. The empty stalk rate was mainly controlled by non-additive genetic effect. The contribution rate of additive genetic effects to the traits related to yield and density increased with the increase of planting density. The yield of maize inbred lines, empty stalk rate, lodging rate, and stalk strength were all normally distributed. With the increase of planting density, the average value of yield GCA increased by 0.28, and the average value of empty stalk rate GCA decreased 0.21, the lodging rate GCA average decreased by 0.03, and the stem GCA average increased by 0.02. The yield of maize hybrids was closely related to the GCA of corn inbred lines (r = 0.877 **, r = 0.811 **, r = 0.672 **). With the increase of planting density, the number of stable maize inbred lines and hybrid combinations is on the rise. Therefore, to strengthen the pressure of adversity selection and implement the strategy of high density selection is an effective measure to enhance the density and lodging resistance of maize inbred lines, enhance the general combining ability and realize the yield gain.