Table_2_Genomic Regions From an Iranian Landrace Increase Kernel Size in Durum Wheat.xlsx

Kernel size and shape are important parameters determining the wheat profitability, being main determinants of yield and its technological quality. In this study, a segregating population of 118 recombinant inbred lines, derived from a cross between the Iranian durum landrace accession “Iran_249” and the Iranian durum cultivar “Zardak”, was used to investigate durum wheat kernel morphology factors and their relationships with kernel weight, and to map the corresponding QTLs. A high density genetic map, based on wheat 90k iSelect Infinium SNP assay, comprising 6,195 markers, was developed and used to perform the QTL analysis for kernel length and width, traits related to kernel shape and weight, and heading date, using phenotypic data from three environments. Overall, a total of 31 different QTLs and 9 QTL interactions for kernel size, and 21 different QTLs and 5 QTL interactions for kernel shape were identified. The landrace Iran_249 contributed the allele with positive effect for most of the QTLs related to kernel length and kernel weight suggesting that the landrace might have considerable potential toward enhancing the existing gene pool for grain shape and size traits and for further yield improvement in wheat. The correlation among traits and co-localization of corresponding QTLs permitted to define 11 clusters suggesting causal relationships between simplest kernel size trait, like kernel length and width, and more complex secondary trait, like kernel shape and weight related traits. Lastly, the recent release of the T. durum reference genome sequence allowed to define the physical interval of our QTL/clusters and to hypothesize novel candidate genes inspecting the gene content of the genomic regions associated to target traits.

籽粒大小与形状是决定小麦种植效益的关键参数，亦是产量及其加工品质的核心决定因素。本研究以伊朗硬粒小麦地方品种"Iran_249"与伊朗硬粒小麦栽培品种"Zardak"杂交衍生的118份重组自交系（recombinant inbred lines）分离群体为材料，探究硬粒小麦籽粒形态相关性状及其与粒重的关联，并对相应的数量性状位点（Quantitative Trait Locus, QTL）进行定位。基于小麦90k iSelect Infinium单核苷酸多态性（SNP）分型芯片，构建了包含6195个标记的高密度遗传连锁图谱，并利用3个环境下的表型鉴定数据，针对籽粒长度、宽度，籽粒形状与粒重相关性状以及抽穗期开展QTL分析。最终共鉴定出31个与籽粒大小相关的独立QTL及9个QTL互作位点，以及21个与籽粒形状相关的独立QTL及5个QTL互作位点。地方品种Iran_249为多数与籽粒长度、粒重相关的QTL贡献了增效等位基因，提示该地方品种在丰富小麦籽粒形状与大小相关基因库、进一步提升小麦产量方面具备可观潜力。性状间的相关性及对应QTL的共定位分析，共定义了11个QTL簇，表明籽粒长宽这类基础籽粒大小性状与籽粒形状、粒重相关这类复杂次级性状之间存在因果关联。此外，随着硬粒小麦参考基因组序列的最新发布，本研究得以明确各QTL/簇的物理区间，并通过解析靶标性状关联基因组区域的基因组成，推测出潜在的新型候选基因。