陆地棉铃-叶系统干物质重发育的杂种优势分析

Heterosis of Dry Matter of Boll-Leaf System in Different Development Stages of Upland Cotton(Gossypium hirsutum L.)

利用6个棉铃性状具有较大差异的陆地棉品种(系),按照完全双列杂交方式配制杂交群体,应用加-显遗传模型估算该群体铃-叶系统各组分(子棉、铃壳、对位果枝叶)干物质重不同发育时期的杂种优势表现,并对不同组分杂种优势的相关性进行了研究。结果表明,多数铃期铃重具有极显著的正向平均优势,但随着生育进程的推进趋于减弱;铃龄10 d时铃重具有极显著的正向超亲优势,此后下降,到成熟吐絮时达到显著的负向超亲优势。铃壳重的超亲优势以负向为主,除铃龄17 d外,其余时期的平均优势表现为极显著的正值。铃龄45 d对位果枝叶重的平均优势和超亲优势达到最大,平均值分别为8.64%、6.54%,优势组合率分别为100%、86.67%,而其他时期趋于0或为负值。铃龄17 d的铃壳重与铃龄45 d、52 d的铃重超亲优势呈显著或极显著正相关。铃龄17 d对位果枝叶重与铃龄17 d、24 d和31 d的铃重超亲优势呈显著或极显著正相关。表明铃龄17 d对位果枝叶、铃壳的发育状况对后期铃重的提高影响较大。

Thirsty F1 combinations were made from 6 varieties(lines) varying in boll characters according to complete diallel crossing design.The heterosis of dry matter weight of components of boll-leaf system(seed cotton,boll shell,subtending leaf of boll) in different boll development stages was evaluated using additive-dominance genetic model.The correlations among them were investigated.The results showed that boll weight expressed very significant and positive F1 heterosis over mid-parent based on population mean(HMP) in most boll-development stages,which decreased along with the developmental course of cotton boll.Boll weight exhibited very significant and positive F1 heterosis over better parent based on population mean(HBP) at 10 d after flowering(DAF),hereafter decreased to the minimum at cotton boll opening.Boll shell weight mainly gave negative F1 HBP throughout the boll development,and statistically very significant and positive F1 HMP heterosis except 17 DAF.There existed the maximum HMP and HBP for the dry weight of the subtending leaf of cotton boll at 45 DAF with the average value of 8.64%,6.54% respectively,and the ratios of the crosses showing positive F1 HMP and HBP to total crosses were 100% and 86.67% respectively.Vary low or negative F1 heterosis was found for the dry weight of the subtending leaf of cotton boll at the other boll-development stages.The F1 HBP of boll shell weight at 17 DAF was positively correlated with that of boll weight at 45,52 DAF at 0.05/0.01 level.The F1 HBP of the dry weight of subtending leaf at 17 DAF showed positive and significant associations with that of boll weight at 17,24,31 DAF at 0.05/0.01 level.These results suggested that the boll weight at boll opening were influenced by the development condition of the subtending leaf of cotton boll and boll shell at 17 DAF.