School of Life Sciences and Basic Medicine, Xinxiang University, Xinxiang, 453003, China.
School of Life Science and Technology, Collaborative Innovation Center of Modern Biological Breeding, Henan Province, Henan Institute of Science and Technology, Xinxiang, 453003, China.
BMC Plant Biol. 2022 Mar 26;22(1):146. doi: 10.1186/s12870-022-03544-6.
Kernel number per spike (KNS) and spike length (SL) are important spike-related traits in wheat variety improvement. Discovering genetic loci controlling these traits is necessary to elucidate the genetic basis of wheat yield traits and is very important for marker-assisted selection breeding.
In the present study, we used a recombinant inbred line population with 248 lines derived from the two founder genotypes of wheat, Bima4 and BainongAK58, to construct a high-density genetic map using wheat 55 K genotyping assay. The final genetic linkage map consists of 2356 bin markers (14,812 SNPs) representing all 21 wheat chromosomes, and the entire map spanned 4141.24 cM. A total of 7 and 18 QTLs were identified for KNS and SL, respectively, and they were distributed on 11 chromosomes. The allele effects of the flanking markers for 12 stable QTLs, including four QTLs for KNS and eight QTLs for SL, were estimated based on phenotyping data collected from 15 environments in a diverse wheat panel including 384 elite cultivars and breeding lines. The positive alleles at seven loci, namely, QKns.his-7D2-1, QKns.his-7D2-2, QSl.his-4A-1, QSl.his-5D1, QSl.his-4D2-2, QSl.his-5B and QSl.his-5A-2, significantly increased KNS or SL in the diverse panel, suggesting they are more universal in their effects and are valuable for gene pyramiding in breeding programs. The transmission of Bima4 allele indicated that the favorite alleles at five loci (QKns.his-7D2-1, QSl.his-5A-2, QSl.his-2D1-1, QSl.his-3A-2 and QSl.his-3B) showed a relatively high frequency or an upward trend following the continuity of generations, suggesting that they underwent rigorous selection during breeding. At two loci (QKns.his-7D2-1 and QSl.his-5A-2) that the positive effects of the Bima4 alleles have been validated in the diverse panel, two and one kompetitive allele-specific PCR (KASP) markers were further developed, respectively, and they are valuable for marker-assisted selection breeding.
Important chromosome regions controlling KNS and SL were identified in the founder parents. Our results are useful for knowing the molecular mechanisms of founder parents and future molecular breeding in wheat.
在小麦品种改良中，每个棘突的核数（KNS）和棘突长度（SL）是重要的棘突相关特征。发现控制这些特征的遗传基因座对于阐明小麦产量性状的遗传基础非常重要，并且对标记辅助选择育种也非常重要。
在本研究中，我们使用了一个由两个小麦起始基因型 Bima4 和 BainongAK58 衍生的 248 个重组自交系群体，使用小麦 55K 基因分型测定法构建了一个高密度遗传图谱。最终的遗传连锁图谱由 2356 个 bin 标记（14812 个 SNP）组成，代表 21 个小麦染色体，整个图谱跨越 4141.24cM。共鉴定到 7 个和 18 个分别控制 KNS 和 SL 的 QTL，它们分布在 11 条染色体上。基于来自包括 384 个优良品种和育种系在内的不同小麦群体的 15 个环境的表型数据，对 12 个稳定 QTL 的侧翼标记的等位基因效应进行了估计，包括 4 个 KNS QTL 和 8 个 SL QTL。在不同群体中，七个位点的正等位基因，即 QKns.his-7D2-1、QKns.his-7D2-2、QSl.his-4A-1、QSl.his-5D1、QSl.his-4D2-2、QSl.his-5B 和 QSl.his-5A-2，显著增加了 KNS 或 SL，表明它们在效应上更普遍，并且在育种计划中用于基因聚合是有价值的。Bima4 等位基因的传递表明，五个位点（QKns.his-7D2-1、QSl.his-5A-2、QSl.his-2D1-1、QSl.his-3A-2 和 QSl.his-3B）的有利等位基因在经过连续几代后，表现出相对较高的频率或上升趋势，这表明它们在育种过程中经历了严格的选择。在两个经过验证的 Bima4 等位基因具有正效应的位点（QKns.his-7D2-1 和 QSl.his-5A-2），分别开发了两个和一个竞争性等位基因特异性 PCR（KASP）标记，它们对标记辅助选择育种具有重要价值。
在起始亲本中鉴定到控制 KNS 和 SL 的重要染色体区域。我们的结果有助于了解起始亲本的分子机制，为未来的小麦分子育种提供参考。
