College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China.
Biology Department, Saint Mary's University, 923 Robie Street, Halifax, NS, B3H 3C3, Canada.
Sci Rep. 2019 Dec 11;9(1):18823. doi: 10.1038/s41598-019-53620-5.
Grain filling is an important growth process in formation of yield and quality for barley final yield determination. To explore the grain development behavior during grain filling period in barley, a high-density genetic map with 1962 markers deriving from a doubled haploid (DH) population of 122 lines was used to identify dynamic quantitative trait locus (QTL) for grain filling rate (GFR) and five grain size traits: grain area (GA), grain perimeter (GP), grain length (GL), grain width (GW) and grain diameter (GD). Unconditional QTL mapping is to detect the cumulative effect of genetic factors on a phenotype from development to a certain stage. Conditional QTL mapping is to detect a net effect of genetic factors on the phenotype at adjacent time intervals. Using unconditional, conditional and covariate QTL mapping methods, we successfully detected 34 major consensus QTLs. Moreover, certain candidate genes related to grain size, plant height, yield, and starch synthesis were identified in six QTL clusters, and individual gene was specifically expressed in different grain filling stages. These findings provide useful information for understanding the genetic basis of the grain filling dynamic process and will be useful for molecular marker-assisted selection in barley breeding.
籽粒灌浆是大麦产量和品质形成的重要生长过程，对最终产量起决定性作用。为了研究大麦灌浆期籽粒发育行为，利用来源于 122 个株系的双单倍体（DH）群体的 1962 个标记，构建了高密度遗传图谱，用于鉴定灌浆速率（GFR）和五个粒形性状的动态数量性状位点（QTL）：粒面积（GA）、粒周长（GP）、粒长（GL）、粒宽（GW）和粒直径（GD）。条件 QTL 作图是检测遗传因素对特定阶段表型的累积效应，而无条件 QTL 作图是检测相邻时间间隔遗传因素对表型的净效应。利用无条件、条件和协变量 QTL 作图方法，成功检测到 34 个主要共识 QTL。此外，在六个 QTL 簇中鉴定到与粒形、株高、产量和淀粉合成相关的某些候选基因，并且个别基因在不同的灌浆阶段特异性表达。这些发现为了解籽粒灌浆动态过程的遗传基础提供了有用信息，将有助于大麦分子标记辅助选择育种。
