Department Of Crop and Soil Environmental Sciences, Virginia Tech, Blacksburg, Virginia, United States of America.
Eastern Regional Small Grains Genotyping Laboratory, USDA-ARS, Raleigh, North Carolina, United States of America.
PLoS One. 2019 Feb 22;14(2):e0208217. doi: 10.1371/journal.pone.0208217. eCollection 2019.
Grain yield is a trait of paramount importance in the breeding of all cereals. In wheat (Triticum aestivum L.), yield has steadily increased since the Green Revolution, though the current rate of increase is not forecasted to keep pace with demand due to growing world population and increasing affluence. While several genome-wide association studies (GWAS) on yield and related component traits have been performed in wheat, the previous lack of a reference genome has made comparisons between studies difficult. In this study, a GWAS for yield and yield-related traits was carried out on a population of 322 soft red winter wheat lines across a total of four rain-fed environments in the state of Virginia using single-nucleotide polymorphism (SNP) marker data generated by a genotyping-by-sequencing (GBS) protocol. Two separate mixed linear models were used to identify significant marker-trait associations (MTAs). The first was a single-locus model utilizing a leave-one-chromosome-out approach to estimating kinship. The second was a sub-setting kinship estimation multi-locus method (FarmCPU). The single-locus model identified nine significant MTAs for various yield-related traits, while the FarmCPU model identified 74 significant MTAs. The availability of the wheat reference genome allowed for the description of MTAs in terms of both genetic and physical positions, and enabled more extensive post-GWAS characterization of significant MTAs. The results indicate a number of promising candidate genes contributing to grain yield, including an ortholog of the rice aberrant panicle organization (APO1) protein and a gibberellin oxidase protein (GA2ox-A1) affecting the trait grains per square meter, an ortholog of the Arabidopsis thaliana mother of flowering time and terminal flowering 1 (MFT) gene affecting the trait seeds per square meter, and a B2 heat stress response protein affecting the trait seeds per head.
谷物产量是所有谷物品种选育中至关重要的一个性状。在小麦（Triticum aestivum L.）中，自绿色革命以来，产量稳步提高，但由于世界人口增长和生活水平提高，预计目前的增长率无法跟上需求。尽管已经在小麦中进行了几项与产量和相关组成性状相关的全基因组关联研究（GWAS），但由于缺乏参考基因组，使得研究之间的比较变得困难。在这项研究中，利用基因型测序（GBS）协议生成的单核苷酸多态性（SNP）标记数据，在弗吉尼亚州的四个雨养环境中对 322 个软红冬小麦品系进行了产量和产量相关性状的 GWAS。使用两种单独的混合线性模型来识别显著的标记-性状关联（MTA）。第一种是单基因座模型，利用单亲系外推法估计亲缘关系。第二种是子集合亲缘关系估计多基因座方法（FarmCPU）。单基因座模型确定了九个与各种产量相关性状相关的显著 MTA，而 FarmCPU 模型确定了 74 个显著 MTA。小麦参考基因组的可用性允许根据遗传和物理位置描述 MTA，并能够更广泛地对显著 MTA 进行 GWAS 后特征描述。研究结果表明，有许多有前途的候选基因与粒重有关，包括水稻异常穗组织（APO1）蛋白的同源物和一个影响每平方米粒数的赤霉素氧化酶蛋白（GA2ox-A1），一个影响每平方米粒数的拟南芥开花时间和终端开花 1（MFT）基因的同源物，以及一个影响每穗粒数的 B2 热应激反应蛋白。
