DataSheet_1_QTL mapping of yield components and kernel traits in wheat cultivars TAM 112 and Duster.pdf

In the Southern Great Plains, wheat cultivars have been selected for a combination of outstanding yield and drought tolerance as a long-term breeding goal. To understand the underlying genetic mechanisms, this study aimed to dissect the quantitative trait loci (QTL) associated with yield components and kernel traits in two wheat cultivars `TAM 112' and `Duster' under both irrigated and dryland environments. A set of 182 recombined inbred lines (RIL) derived from the cross of TAM 112/Duster were planted in 13 diverse environments for evaluation of 18 yield and kernel related traits. High-density genetic linkage map was constructed using 5,081 single nucleotide polymorphisms (SNPs) from genotyping-by-sequencing (GBS). QTL mapping analysis detected 134 QTL regions on all 21 wheat chromosomes, including 30 pleiotropic QTL regions and 21 consistent QTL regions, with 10 QTL regions in common. Three major pleiotropic QTL on the short arms of chromosomes 2B (57.5 - 61.6 Mbps), 2D (37.1 - 38.7 Mbps), and 7D (66.0 - 69.2 Mbps) colocalized with genes Ppd-B1, Ppd-D1, and FT-D1, respectively. And four consistent QTL associated with kernel length (KLEN), thousand kernel weight (TKW), plot grain yield (YLD), and kernel spike-1 (KPS) (Qklen.tamu.1A.325, Qtkw.tamu.2B.137, Qyld.tamu.2D.3, and Qkps.tamu.6A.113) explained more than 5% of the phenotypic variation. QTL Qklen.tamu.1A.325 is a novel QTL with consistent effects under all tested environments. Marker haplotype analysis indicated the QTL combinations significantly increased yield and kernel traits. QTL and the linked markers identified in this study will facilitate future marker-assisted selection (MAS) for pyramiding the favorable alleles and QTL map-based cloning.

在美国南部大平原（Southern Great Plains）区域，小麦品种选育长期以来将兼顾优异产量与抗旱性作为核心育种目标。为解析其内在遗传机制，本研究旨在剖析灌溉与旱地两种栽培环境下，两个小麦品种‘TAM 112’与‘Duster’的产量构成性状及籽粒相关性状所关联的数量性状位点（quantitative trait loci, QTL）。本研究以TAM 112与Duster杂交衍生的182个重组自交系（recombined inbred lines, RIL）群体为材料，在13个多样化的试验环境中开展种植试验，对18个产量及籽粒相关性状进行表型鉴定。利用基于基因型分型测序（genotyping-by-sequencing, GBS）获得的5081个单核苷酸多态性（single nucleotide polymorphisms, SNPs）标记，构建了高密度遗传连锁图谱。QTL定位分析在小麦全部21条染色体上共检测到134个QTL区域，其中包含30个多效性QTL（pleiotropic QTL）区域与21个稳定性QTL（consistent QTL）区域，且有10个QTL区域为两类位点所共有。位于染色体2B短臂（57.5~61.6 Mb）、2D短臂（37.1~38.7 Mb）及7D短臂（66.0~69.2 Mb）上的3个主要多效性QTL，分别与Ppd-B1、Ppd-D1及FT-D1基因共定位。另有4个与籽粒长度（kernel length, KLEN）、千粒重（thousand kernel weight, TKW）、小区籽粒产量（plot grain yield, YLD）及单穗籽粒数（kernel spike-1, KPS）相关的稳定性QTL，其表型变异解释率均超过5%，对应的QTL分别为Qklen.tamu.1A.325、Qtkw.tamu.2B.137、Qyld.tamu.2D.3及Qkps.tamu.6A.113。QTL Qklen.tamu.1A.325为新鉴定的QTL，在所有供试环境中均表现出稳定的遗传效应。标记单倍型分析表明，这些QTL的组合可显著提升产量及籽粒相关性状的表现。本研究鉴定得到的QTL及其连锁标记，将为后续通过标记辅助选择（marker-assisted selection, MAS）聚合优良等位基因以及QTL图位克隆提供重要支撑。