Department of Plant and Environmental Sciences, University of Copenhagen, Højbakkegård Allé 13, 2630 Taastrup, Denmark.
Wheat Breeding Group, Plant Breeding and Genetics Division, Nuclear Institute for Agriculture and Biology, Faisalabad 38000, Pakistan.
Int J Mol Sci. 2020 Apr 30;21(9):3156. doi: 10.3390/ijms21093156.
Terminal drought stress poses a big challenge to sustain wheat grain production in rain-fed environments. This study aimed to utilize the genetically diverse pre-breeding lines for identification of genomic regions associated with agro-physiological traits at terminal stage drought stress in wheat. A total of 339 pre-breeding lines panel derived from three-way crosses of 'exotics × elite × elite' lines were evaluated in field conditions at Obregon, Mexico for two years under well irrigated as well as drought stress environments. Drought stress was imposed at flowering by skipping the irrigations at pre and post anthesis stage. Results revealed that drought significantly reduced grain yield (Y), spike length (SL), number of grains spikes (NGS) and thousand kernel weight (TKW), while kernel abortion (KA) was increased. Population structure analysis in this panel uncovered three sub-populations. Genome wide linkage disequilibrium (LD) decay was observed at 2.5 centimorgan (cM). The haplotypes-based genome wide association study (GWAS) identified significant associations of Y, SL, and TKW on three chromosomes; 4A (HB10.7), 2D (HB6.10) and 3B (HB8.12), respectively. Likewise, associations on chromosomes 6B (HB17.1) and 3A (HB7.11) were found for NGS while on chromosome 3A (HB7.12) for KA. The genomic analysis information generated in the study can be efficiently utilized to improve Y and/or related parameters under terminal stage drought stress through marker-assisted breeding.
终端干旱胁迫对雨养环境下维持小麦籽粒生产构成了巨大挑战。本研究旨在利用遗传多样性的预繁殖系，鉴定与小麦终端干旱胁迫期农艺生理特性相关的基因组区域。总共 339 个预繁殖系面板来源于三种杂交 '外来种 × 优秀品系 × 优秀品系' ，在墨西哥奥布雷贡的田间条件下进行了两年的评估，在充分灌溉和干旱胁迫环境下进行。在开花期通过跳过授粉前和授粉后的灌溉来施加干旱胁迫。结果表明，干旱显著降低了籽粒产量（Y）、穗长（SL）、穗粒数（NGS）和千粒重（TKW），而籽粒败育（KA）增加。该面板中的群体结构分析揭示了三个亚群。在该面板中观察到全基因组连锁不平衡（LD）衰减在 2.5 厘摩（cM）处。基于单倍型的全基因组关联研究（GWAS）在三个染色体上鉴定到 Y、SL 和 TKW 的显著关联；4A（HB10.7）、2D（HB6.10）和 3B（HB8.12），分别。同样，在染色体 6B（HB17.1）和 3A（HB7.11）上发现了 NGS 的关联，而在染色体 3A（HB7.12）上发现了 KA 的关联。本研究中生成的基因组分析信息可通过标记辅助育种有效地用于提高终端干旱胁迫下的 Y 和/或相关参数。
