转基因抗虫棉品种间杂交F_1、F_2竞争优势分析

Analysis on Competitive Heterosis of Hybrid F_1 and F_2 between Transgenic Bt Varieties of Upland Cotton

【目的】分析评估多个转基因抗虫棉品种间杂交F_1、F_2产量与纤维品质性状,为强优势组合选育以及F_2利用的可行性提供依据。【方法】以10个综合性状优良的陆地棉新品种(系)作亲本,组配10个杂交组合,从中筛选出产量竞争优势突出的4个组合,进行F_1、F_2产量与纤维品质性状分析。【结果】棉花品种间杂交F_1表现出较强的产量竞争优势,但年际差异较大,越是在产量水平较低的年份,杂交种产量竞争优势越突出。除个别组合外,F_2产量竞争优势减退明显,铃重降低是其主要原因。F_2纤维品质指标总体上较F_1下降,极差和变异系数增大。各品质性状的变异系数远低于产量构成要素的变异系数,总的趋势是F_1<常规对照品种鲁棉研28号(CK)、F_2>F_1。不同组合F_1、F_2代产量和纤维品质性状的竞争优势差异较大,从中筛选出1个优势组合,其F_1、F_2产量均具竞争优势,且F_2产量竞争优势减退小、纤维品质优良、分离轻。【结论】转基因抗虫棉品种间杂交种抗逆性强、稳产性好。父母本纤维品质好、差异小的组合,F_2纤维品质优良、分离程度较小。选育生产上有利用价值的F_2优势组合是可行的。

[Objective] The purpose of this study is to supply basis for selecting strong heterosis hybrid and the feasibility of F_2 utilization, by evaluating yield heterosis and fiber quality traits of hybrid F_1 and F_2 generated by transgenic Bt varieties in upland cotton. [Method] Ten upland cotton varieties（lines） with good comprehensive characteristics were selected to produce 10 crosses, and four of them with better competitive heterosis（CH） in yield were screened out to analyze the lint yield and fiber traits of F_1 and F_2. [Result] The results indicated there was a strong CH in yield of F_1, but the yearly variation was large. Hybrids performed better in the poor production year. The CH in yield decreased obviously in most of the F_2 combinations. Further analysis showed that the decrease of boll weight was the main cause of drop of yield CH in F_2. The fiber quality index in F_2 showed a downward trend compared with F_1, and the coefficient of range and variation（CV） increased. The coefficient of variation of quality traits was much lower than that of yield components, with a trend of F_1 SCRC 28（CK） and F_2 F_1. The CH of lint yield and fiber traits changed between F_1 and F_2 in different combinations. We screened out a combination with higher CH of yield in both F_1 and F_2, and with less decreased yield CH, fine fiber quality and light separation in F_2. [Conclusion] The hybrids generated by transgenic Bt varieties in upland cotton characterized by strong adversity resistance and yield stability. Fine fiber quality and light separation in F_2 came from crosses with the parents of fine fiber quality and small differences. So, it is possible for breeders to select valuable F_2 combinations in production.