National Key Laboratory of Crop Genetic Improvement and National Centre of Plant Gene Research (Wuhan), Huazhong Agricultural University, Wuhan, China.
Plant Biotechnol J. 2019 Nov;17(11):2211-2222. doi: 10.1111/pbi.13134. Epub 2019 Apr 29.
Combining ability is a measure for selecting elite parents and predicting hybrid performance in plant breeding. However, the genetic basis of combining ability remains unclear and a global view of combining ability from diverse mating designs is lacking. We developed a North Carolina II (NCII) population of 96 Oryza sativa and four male sterile lines to identify parents of greatest value for hybrid rice production. Statistical analyses indicated that general combining ability (GCA) and specific combining ability (SCA) contributed variously to different agronomic traits. In a genome-wide association study (GWAS) of agronomic traits, GCA and SCA, we identified 34 significant associations (P < 2.39 × 10 ). The superior alleles of GCA loci (Ghd8, GS3 and qSSR4) accumulated in parental lines with high GCA and explained 30.03% of GCA variance in grain yield, indicating that molecular breeding of high GCA parental lines is feasible. The distinct distributions of these QTLs contributed to the differentiation of parental GCA in subpopulations. GWAS of SCA identified 12 more loci that showed dominance on corresponding agronomic traits. We conclude that the accumulation of superior GCA and SCA alleles is an important contributor to heterosis and QTLs that greatly contributed to combining ability in our study would accelerate the identification of elite inbred lines and breeding of super hybrids.
杂种优势是植物育种中选择优良亲本和预测杂种表现的一种衡量标准。然而，杂种优势的遗传基础仍不清楚，缺乏来自不同交配设计的杂种优势的全局观点。我们开发了一个由 96 个水稻品种和四个雄性不育系组成的北卡罗来纳 II（NCII）群体，以鉴定最适合杂交水稻生产的亲本。统计分析表明，一般配合力（GCA）和特殊配合力（SCA）对不同的农艺性状有不同的贡献。在对农艺性状的全基因组关联研究（GWAS）中，我们鉴定了 34 个显著关联（P < 2.39 × 10-8），包括 GCA 和 SCA。GCA 位点的优良等位基因（Ghd8、GS3 和 qSSR4）在具有高 GCA 的亲本系中积累，并解释了产量的 30.03%的 GCA 变异，表明高 GCA 亲本系的分子育种是可行的。这些 QTL 的不同分布有助于亚群中亲本 GCA 的分化。SCA 的 GWAS 还鉴定了 12 个更多的位点，它们在相应的农艺性状上表现出显性。我们得出结论，优良 GCA 和 SCA 等位基因的积累是杂种优势的一个重要贡献因素，本研究中对配合力有很大贡献的 QTL 将加速优良自交系的鉴定和超级杂交种的培育。
