Department of Agronomy, Horticulture & Plant Science, South Dakota State University, Brookings, SD, 57007, USA.
USDA-ARS, Hard Winter Wheat Genetics Research Unit, Manhattan, KS, 66506, USA.
Theor Appl Genet. 2022 Sep;135(9):2953-2967. doi: 10.1007/s00122-022-04160-6. Epub 2022 Aug 8.
Genetic dissection of yield component traits including spike and kernel characteristics is essential for the continuous improvement in wheat yield. Genome-wide association studies (GWAS) have been frequently used to identify genetic determinants for spike and kernel-related traits in wheat, though none have been employed in hard winter wheat (HWW) which represents a major class in US wheat acreage. Further, most of these studies relied on assembled diversity panels instead of adapted breeding lines, limiting the transferability of results to practical wheat breeding. Here we assembled a population of advanced/elite breeding lines and well-adapted cultivars and evaluated over four environments for phenotypic analysis of spike and kernel traits. GWAS identified 17 significant multi-environment marker-trait associations (MTAs) for various traits, representing 12 putative quantitative trait loci (QTLs), with five QTLs affecting multiple traits. Four of these QTLs mapped on three chromosomes 1A, 5B, and 7A for spike length, number of spikelets per spike (NSPS), and kernel length are likely novel. Further, a highly significant QTL was detected on chromosome 7AS that has not been previously associated with NSPS and putative candidate genes were identified in this region. The allelic frequencies of important quantitative trait nucleotides (QTNs) were deduced in a larger set of 1,124 accessions which revealed the importance of identified MTAs in the US HWW breeding programs. The results from this study could be directly used by the breeders to select the lines with favorable alleles for making crosses, and reported markers will facilitate marker-assisted selection of stable QTLs for yield components in wheat breeding.
对包括穗部和籽粒特征在内的产量构成性状进行遗传剖析，对于持续提高小麦产量至关重要。全基因组关联研究（GWAS）已被频繁用于鉴定小麦穗部和籽粒相关性状的遗传决定因素，但尚未应用于硬粒冬小麦（HWW），而 HWW 在美国小麦种植面积中占主要地位。此外，这些研究大多依赖于已组装的多样性面板，而不是适应性育种系，限制了研究结果在实际小麦育种中的可转移性。在这里，我们组装了一个先进/精英育种系和适应性良好的品种群体，并在四个环境中对穗部和籽粒性状进行了表型分析。GWAS 鉴定出了 17 个对各种性状有显著影响的多环境标记-性状关联（MTAs），代表了 12 个可能的数量性状位点（QTL），其中 5 个 QTL 影响多个性状。其中四个 QTL 位于 1A、5B 和 7A 三个染色体上，分别影响穗长、穗上小穗数（NSPS）和籽粒长度，可能是新的。此外，在 7AS 染色体上检测到一个高度显著的 QTL，该 QTL 以前与 NSPS 无关，并在该区域鉴定出了假定的候选基因。在一个包含 1124 个品系的更大数据集上推断出了重要数量性状核苷酸（QTN）的等位基因频率，这表明了所鉴定的 MTAs 在 HWW 美国小麦育种计划中的重要性。这项研究的结果可以直接被育种家用来选择有利等位基因的系进行杂交，报道的标记将有助于在小麦育种中对产量构成的稳定 QTL 进行标记辅助选择。
