桂综3号和桂苏综玉米群体相互轮回选择效果分析

【目的】对两个玉米群体桂综3号和桂苏综进行两轮相互轮回选择改良后的遗传效益进行评估，为其利用提供理论依据。【方法】以黄早4、掖478、丹340、M0174个测验种作母本，以两个玉米群体桂综3号和桂苏综不同改良群体作父本，按NCU遗传交配设计组配测交种，对各轮群体、群体间杂交组合和测交种进行田间鉴定，调查产量、株高、穗位高、穗长、穗粗、穗行数、行粒数、秃尖度、出籽率和千粒重并分析配合力等。【结果】桂综3号、桂苏综及其杂交组合产量平均每轮增益分别为83kg／ha（0．85％）、645kg／ha（12．45％）和390kg／ha（5．90％）；群体间杂交组合超亲优势从5．7％提高N13．5％。桂综3号的产量一般配合力效应从-5．32增加到-1．55，桂苏综的一般配合力效应从0．10增加到6．55。桂综3号、桂苏综均与掖478、丹340的特殊配合力都得到一定提高。出籽率和干粒重朝逐轮增加方向发展，秃尖度呈逐轮减少趋势，其他性状变化不明显。【结论】桂综3号和桂苏综经两轮相互轮回选择后，群体问杂交组合产量和杂种优势都逐轮增加，易与掖478、丹340等Reid、旅大红骨种质形成杂种优势模式，可继续进行相互轮回选择改良，利于在玉米育种上改良利用。

Analysis of reciprocal recurrent selection in composited populations of Guizong 3 and Guisuzong

[Objective ]The genetic gains of composited populations Guizong 3 and Guisuzong after genetic improvement using two cycles of reciprocal recurrent selection were evaluated in order to provide theoretical references for breeding application. [Method]A NC Ⅱ mating experimental trial was designed using testers Huangzao 4, Ye 478, Dan 340 and Mo 17 as female and the genetic improved population Guizong 3 and Guisuzong as male. A complete random block design with three repetitions was applied to evaluate the effects of the selection among all the cycles of populations, the inter- population crosses and the testcrosses. The traits were investigated in this experiment including yield, plant height, ear height, ear length, ear width, rows per ear, grains per row, bear tip, grain yield ratio and 1000-grain weight and combining ability. [Result ]The results showed that the yields of Guizong 3 and Guisuzong and their testcrosses averagely increased by 83 kg/ha（0.85%）, 645 kg/ha（12.45%）and 390 kg/ha （5.90% ）in per cycle selection, respectively. And the heterobeltiosis of inter-population crosses （MC0xSC0） increased from 5.7% to 13.5%. The yield general combining ability of Guizong 3 rose from -5.32 to -1.55, and that of Guisuzong increased from 0.10 to 6.55. The specific combining ability between Guizong 3, Guisuzong and Ye 478, Dan 340 improved in different extent. The genetic gains of grain yield ratio and 1000-grain weight increased with the improvement cycles, and that of bear tip decreased with the improvement cycles increase, while the other traits remained almost the same during the improvements. [ Conclusion ]After two cycles of reciprocal recurrent selection, the yield and heterosis of Guizong 3 and Guisuzong inter-population crosses increased and it is easy for these two populations to form the heterotic model with the Ye 478, Dan 340. Guizong 3 and Guisuzong could keep on reciprocal recurrent selection which will benefit the breeding in Guangxi.