Identification of genetic loci for flag-leaf-related traits in wheat (Triticum aestivum L.) and their effects on grain yield

Ying Wang; Ling Qiao; Chenkang Yang; Xiaohua Li; Jiajia Zhao; Bangbang Wu; Xingwei Zheng; Pengbo Li; Jun Zheng

doi:10.3389/fpls.2022.990287

Identification of genetic loci for flag-leaf-related traits in wheat (Triticum aestivum L.) and their effects on grain yield

Front Plant Sci. 2022 Sep 8:13:990287. doi: 10.3389/fpls.2022.990287. eCollection 2022.

Authors

Ying Wang^{1

2}, Ling Qiao¹, Chenkang Yang^{1

2}, Xiaohua Li¹, Jiajia Zhao¹, Bangbang Wu¹, Xingwei Zheng¹, Pengbo Li³, Jun Zheng¹

Affiliations

¹ Institute of Wheat Research, Shanxi Agricultural University, Linfen, China.
² School of Life Sciences, Shanxi University, Taiyuan, China.
³ Institute of Cotton Research, Shanxi Agricultural University, Yuncheng, China.

Abstract

Flag-leaf-related traits including length (FLL), width (FLW), area (FLA), thickness (FLT), and volume (FLV) of flag leaves are the most important determinants of plant architecture and yield in wheat. Understanding the genetic basis of these traits could accelerate the breeding of high yield wheat varieties. In this study, we constructed a doubled haploid (DH) population and analyzed flag-leaf-related traits in five experimental locations/years using the wheat 90K single-nucleotide polymorphism array. It's worth noting that a novel method was used to measure FLT and FLV easily. Leaf thickness at two-thirds of the leaf length from tip to collar represented the average leaf thickness as measured with freehand sections and was used to calculate the leaf volume. In addition, flag-leaf-related traits showed positive correlations with yield related traits under two different water regimes. A total of 79 quantitative trait loci (QTL) controlling the five traits were detected among all chromosomes except 4D and 5A, explaining 3.09-14.52% of the phenotypic variation. Among them, 15 stable QTL were identified in more than three environments, including two major QTL for FLT, six for FLW, three for FLA, two for FLT and two for FLV. DH lines with positive alleles at both QTL regions had an average FLL (9.90%), FLW (32.87%), FLT (6.62%), FLA (18.47%), and FLV (20.87%) greater than lines with contrasting alleles. QFLT-2B, QFLV-2A, and QFLV-7D were co-located with yield-related traits. The 15 QTL were validated by tightly linked kompetitive allele specific PCR (KASP) markers in a recombinant inbred line (RIL) population derived from a different cross. QFLL-4A, QFLW-4B, QFLA-5D.1, QFLA-7A, QFLA-7D.1, QFLT-2B, QFLT-6A, QFLV-2A, and QFLV-7D are likely novel loci. These results provide a better understanding of the genetic basis underlying flag-leaf-related traits. Also, target regions for fine mapping and marker-assisted selection were identified and these will be valuable for breeding high yielding bread wheat.

Keywords: flag leaf; flag leaf volume measurement; grain; quantitative trait loci; wheat.