State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Sichuan Agricultural University, Chengdu, 611130, China.
Triticeae Research Institute, Sichuan Agricultural University, Chengdu, 611130, China.
Theor Appl Genet. 2019 Nov;132(11):3155-3167. doi: 10.1007/s00122-019-03415-z. Epub 2019 Aug 21.
A major and stably expressed QTL for spikelet number per spike identified in a 2-cM interval on chromosome arm 2DS was validated using two populations with different genetic backgrounds. Spikelet number per spike (SNS) plays a key role in wheat yield improvement. Numerous genetic and environmental factors influencing SNS have been documented, but the number of major, stably expressed and validated loci underlying SNS is still limited. In this study, a recombinant inbred line (RIL) population derived from a normal spikelet cultivar and a multiple-spikelet wheat line (with a longer spike with more canonically oriented apical spikelets) was genotyped using a Wheat55K single-nucleotide polymorphism (SNP) array and simple sequence repeat (SSR) markers. SNS was measured for this RIL population in eight environments. Five QTL were each identified in two or more environments. One of them, QSns.sau-2D (LOD = 3.47-38.24, PVE = 10.16-45.68%), was detected in all the eight environments. The QTL was located in a 2-cM interval on chromosome arm 2DS flanked by the markers AX-109836946 and AX-111956072. This QTL, QSns.sau-2D, significantly increased SNS by up to 14.72%. Several genes associated with plant growth and development were identified in the physical interval of QSns.sau-2D. This QTL was further validated by the tightly linked Kompetitive Allele Specific PCR (KASP) marker, KASP-AX-94721936, in two other populations with different genetic backgrounds. The significant correlation between SNS and anthesis date, plant height, spike length, grain number per spike and thousand-grain weight were detected and discussed. These results lay the foundation for fine mapping and cloning gene(s) underlying QSns.sau-2D.
在 2DS 染色体臂上一个 2cM 区间内鉴定到一个控制小穗数的主效且稳定表达的 QTL，利用遗传背景不同的两个群体对其进行了验证。小穗数在小麦产量改良中起着关键作用。已经记录了许多影响小穗数的遗传和环境因素，但控制小穗数的主效、稳定表达和已验证的基因座数量仍然有限。在这项研究中，利用小麦 55K 单核苷酸多态性（SNP）芯片和简单重复序列（SSR）标记对来自正常小穗品种和多小穗小麦品系（具有更长的穗和更多的顶端小穗）的重组自交系（RIL）群体进行了基因型分析。在 8 个环境中对这个 RIL 群体进行了小穗数的测量。在两个或更多环境中鉴定到 5 个 QTL。其中一个 QTL，QSns.sau-2D（LOD=3.47-38.24，PVE=10.16-45.68%），在所有 8 个环境中均被检测到。该 QTL位于染色体臂 2DS 上 AX-109836946 和 AX-111956072 标记之间的 2cM 区间内。该 QTL 显著增加小穗数，最多增加 14.72%。在 QSns.sau-2D 的物理区间内鉴定到了几个与植物生长发育相关的基因。在具有不同遗传背景的另外两个群体中，通过紧密连锁的 Kompetitive Allele Specific PCR（KASP）标记 KASP-AX-94721936 对该 QTL 进行了进一步验证。在两个具有不同遗传背景的群体中检测到并讨论了小穗数与开花期、株高、穗长、小穗粒数和千粒重之间的显著相关性。这些结果为 QSns.sau-2D 基因的精细定位和克隆奠定了基础。
