Dang Xiaojing, Thi Thu Giang Tran, Dong Guanshan, Wang Hui, Edzesi Wisdom Mawuli, Hong Delin
State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, 210095, China.
Planta. 2014 Jun;239(6):1309-19. doi: 10.1007/s00425-014-2060-z. Epub 2014 Mar 26.
Seed vigor is closely related to direct seeding in rice (Oryza sativa L.). Previous quantitative trait locus (QTL) studies for seed vigor were mainly derived from bi-parental segregating populations and no report from natural populations. In this study, association mapping for seed vigor was performed on a selected sample of 540 rice cultivars (419 from China and 121 from Vietnam). Population structure was estimated on the basis of 262 simple sequence repeat (SSR) markers. Seed vigor was evaluated by root length (RL), shoot length (SL) and shoot dry weight in 2011 and 2012. Abundant phenotypic and genetic diversities were found in the studied population. The population was divided into seven subpopulations, and the levels of linkage disequilibrium (LD) ranged from 10 to 80 cM. We identified 27 marker-trait associations involving 18 SSR markers for three traits. According to phenotypic effects for alleles of the detected QTLs, elite alleles were mined. These elite alleles could be used to design parental combinations and the expected results would be obtained by pyramiding or substituting the elite alleles per QTL (apart from possible epistatic effects). Our results demonstrate that association mapping can complement and enhance previous QTL information for marker-assisted selection and breeding by design.
种子活力与水稻直播密切相关。以往关于种子活力的数量性状位点（QTL）研究主要来自双亲分离群体，尚无来自自然群体的报道。本研究对540个水稻品种（419个来自中国，121个来自越南）的选定样本进行了种子活力关联分析。基于262个简单序列重复（SSR）标记估计群体结构。在2011年和2012年通过根长（RL）、苗长（SL）和地上部干重评估种子活力。在所研究的群体中发现了丰富的表型和遗传多样性。该群体被分为7个亚群，连锁不平衡（LD）水平范围为10至80 cM。我们鉴定出27个标记-性状关联，涉及18个SSR标记与三个性状。根据检测到的QTL等位基因的表型效应，挖掘出优异等位基因。这些优异等位基因可用于设计亲本组合，通过每个QTL的优异等位基因聚合或替换有望获得预期结果（除可能的上位性效应外）。我们的结果表明，关联分析可以补充和增强先前的QTL信息，用于标记辅助选择和设计育种。
