两个玉米群体的构建及其改良效果

【目的】通过群体的创建和改良，扩大玉米种质基础，为广西玉米杂交育种提供新的优良种质。【方法】根据配合力测定和自交系的系谱分析结果和育种目标要求，分别应用37、26个优良自交系创建两个玉米基础群体GZPA和GZPB，应用经简化后的改良HS相互轮回选择法对两个群体进行遗传改良，并对其农艺性状进行测定和遗传增益分析。【结果】经改良后，两群体杂交组合4个试点的平均产量增益为7.70%，其吐丝天数、开花间隙天数、穗长、穗粗、穗行数、行粒数、出籽率、千粒重均获得一定程度的有利增益。GZPA和GZPB平均产量增益分别为5.37%和4.85%；群体GZPA的吐丝天数、开花间隙天数、出籽率为负增益，其他性状为正增益，且株高、穗粗、穗行数的增益达显著水平；群体GZPB的吐丝天数、开花间隙天数、穗长、穗粗、穗行数、行粒数为正增益，其他性状为负增益。两个群体改良前后性状变异系数变化较小。【结论】简化后的改良HS相互轮回选择法对两个群体的改良效果明显，两个群体内仍有较大的遗传变异，可作进一步改良。

Creation and enhancement effect of two maize populations using selfing lines

【Objective】Through creating and modifying the maize populations， the maize germplasm base was amplified in order to provide new germplasm to Guangxi corn breeding programs. 【Method】According to the combining ability test， inbred lines’ pedigree analysis， and relevant breeding requirements， the 37 and 26 inbred lines were used to respectively create two maize based populations GZPA and GZPB， and the simplified and modified HS reciprocal recurrent selection methods were applied on the two genetically improved populaions to analyze their agronomic traits and genetic gain. 【Result】After improvement， the average yield increase of two hybrid populations in four experimental sites was 7.70%， in which the silking days， ASI days， ear length， ear diameter， rows per ear， kernels per row， seed setting rate， and 1000-grain weight all displayed advantageous gain to some extent. The average yield of GZPA and GZPB was 5.37 and 4.85%， respectively. The population GZPA’s silking days， ASI days， and seed setting rate showed negative gain； other traits， on the other hand， exhibited positive gain， and that of the plant height， ear diameter， and rows per ear showed significant difference. The population GZPB’s silking days， ASI days， ear length， ear diameter， rows per ear， and kernels per row all displayed positive gain， while all other traits displayed negative gain. The variance coefficients of the two populations before and after improvements exhibited little changes. 【Conclusion】After the improvements were obviously observed from the two groups applied with the modified HS reciprocal recurrent selection method， the two groups still showed large genetic variations， which could be enhanced further.