Zhang Jinfa, Wu Man, Yu Jiwen, Li Xingli, Pei Wenfeng
Department of Plant and Environmental Sciences, New Mexico State University, Las Cruces, NM, United States of America.
State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, 455000, China.
PLoS One. 2016 Jan 5;11(1):e0143646. doi: 10.1371/journal.pone.0143646. eCollection 2016.
Upland cotton (Gossypium hirstum L.), which produces more than 95% of the world natural cotton fibers, has a narrow genetic base which hinders progress in cotton breeding. Introducing germplasm from exotic sources especially from another cultivated tetraploid G. barbadense L. can broaden the genetic base of Upland cotton. However, the breeding potential of introgression lines (ILs) in Upland cotton with G. barbadense germplasm integration has not been well addressed. This study involved six ILs developed from an interspecific crossing and backcrossing between Upland cotton and G. barbadense and represented one of the first studies to investigate breeding potentials of a set of ILs using a full diallel analysis. High mid-parent heterosis was detected in several hybrids between ILs and a commercial cultivar, which also out-yielded the high-yielding cultivar parent in F1, F2 and F3 generations. A further analysis indicated that general ability (GCA) variance was predominant for all the traits, while specific combining ability (SCA) variance was either non-existent or much lower than GCA. The estimated GCA effects and predicted additive effects for parents in each trait were positively correlated (at P<0.01). Furthermore, GCA and additive effects for each trait were also positively correlated among generations (at P<0.05), suggesting that F2 and F3 generations can be used as a proxy to F1 in analyzing combining abilities and estimating genetic parameters. In addition, differences between reciprocal crosses in F1 and F2 were not significant for yield, yield components and fiber quality traits. But maternal effects appeared to be present for seed oil and protein contents in F3. This study identified introgression lines as good general combiners for yield and fiber quality improvement and hybrids with high heterotic vigor in yield, and therefore provided useful information for further utilization of introgression lines in cotton breeding.
陆地棉（Gossypium hirstum L.）生产了全球95%以上的天然棉纤维，但其遗传基础狭窄，这阻碍了棉花育种的进展。引入外来种质，特别是来自另一种栽培四倍体海岛棉（G. barbadense L.）的种质，可以拓宽陆地棉的遗传基础。然而，陆地棉中整合了海岛棉种质的渐渗系（ILs）的育种潜力尚未得到充分研究。本研究涉及通过陆地棉与海岛棉的种间杂交和回交培育出的6个渐渗系，这是首批使用完全双列分析来研究一组渐渗系育种潜力的研究之一。在几个渐渗系与一个商业品种的杂交组合中检测到了较高的中亲杂种优势，这些杂交组合在F1、F2和F3代的产量也超过了高产品种亲本。进一步分析表明，所有性状的一般配合力（GCA）方差占主导地位，而特殊配合力（SCA）方差不存在或远低于GCA。各性状亲本的估计GCA效应和预测加性效应呈正相关（P<0.01）。此外，各性状的GCA和加性效应在各世代间也呈正相关（P<0.05），这表明在分析配合力和估计遗传参数时，F2和F3代可作为F1代的替代。此外，F1和F2代正反交在产量、产量构成因素和纤维品质性状上的差异不显著。但在F3代，种子油和蛋白质含量似乎存在母本效应。本研究确定渐渗系是提高产量和纤维品质的优良一般配合系，以及具有高产杂种优势的杂交种，因此为棉花育种中渐渗系的进一步利用提供了有用信息。
