Juliana Philomin, Govindan Velu, Crespo-Herrera Leonardo, Mondal Suchismita, Huerta-Espino Julio, Shrestha Sandesh, Poland Jesse, Singh Ravi P
Borlaug Institute for South Asia, Ludhiana, India.
International Maize and Wheat Improvement Center, Texcoco, Mexico.
Front Plant Sci. 2022 Jun 30;13:903819. doi: 10.3389/fpls.2022.903819. eCollection 2022.
Accelerating breeding efforts for developing biofortified bread wheat varieties necessitates understanding the genetic control of grain zinc concentration (GZnC) and grain iron concentration (GFeC). Hence, the major objective of this study was to perform genome-wide association mapping to identify consistently significant genotyping-by-sequencing markers associated with GZnC and GFeC using a large panel of 5,585 breeding lines from the International Maize and Wheat Improvement Center. These lines were grown between 2018 and 2021 in an optimally irrigated environment at Obregon, Mexico, while some of them were also grown in a water-limiting drought-stressed environment and a space-limiting small plot environment and evaluated for GZnC and GFeC. The lines showed a large and continuous variation for GZnC ranging from 27 to 74.5 ppm and GFeC ranging from 27 to 53.4 ppm. We performed 742,113 marker-traits association tests in 73 datasets and identified 141 markers consistently associated with GZnC and GFeC in three or more datasets, which were located on all wheat chromosomes except 3A and 7D. Among them, 29 markers were associated with both GZnC and GFeC, indicating a shared genetic basis for these micronutrients and the possibility of simultaneously improving both. In addition, several significant GZnC and GFeC associated markers were common across the irrigated, water-limiting drought-stressed, and space-limiting small plots environments, thereby indicating the feasibility of indirect selection for these micronutrients in either of these environments. Moreover, the many significant markers identified had minor effects on GZnC and GFeC, suggesting a quantitative genetic control of these traits. Our findings provide important insights into the complex genetic basis of GZnC and GFeC in bread wheat while implying limited prospects for marker-assisted selection and the need for using genomic selection.
加快培育富含生物强化营养的面包小麦品种的育种工作，需要了解籽粒锌浓度（GZnC）和籽粒铁浓度（GFeC）的遗传控制。因此，本研究的主要目标是进行全基因组关联图谱分析，以使用来自国际玉米和小麦改良中心的5585个育种系组成的大型群体，鉴定与GZnC和GFeC相关的一致性显著的简化基因组测序标记。这些品系于2018年至2021年在墨西哥奥布雷贡的最佳灌溉环境中种植，其中一些还在水分限制的干旱胁迫环境和空间限制的小地块环境中种植，并对GZnC和GFeC进行了评估。这些品系的GZnC在27至74.5 ppm之间，GFeC在27至53.4 ppm之间，表现出较大的连续变异。我们在73个数据集中进行了742,113次标记-性状关联测试，鉴定出141个在三个或更多数据集中与GZnC和GFeC一致相关的标记，这些标记位于除3A和7D之外的所有小麦染色体上。其中，29个标记与GZnC和GFeC均相关，表明这些微量营养素具有共同的遗传基础，并且有可能同时提高两者的含量。此外，几个与GZnC和GFeC相关的显著标记在灌溉、水分限制的干旱胁迫和空间限制的小地块环境中是共同的，从而表明在这些环境中的任何一种中对这些微量营养素进行间接选择的可行性。此外，鉴定出的许多显著标记对GZnC和GFeC的影响较小，表明这些性状受数量遗传控制。我们的研究结果为面包小麦中GZnC和GFeC的复杂遗传基础提供了重要见解，同时暗示了标记辅助选择的前景有限以及使用基因组选择的必要性。
