Mini Agathe, Touzy Gaëtan, Beauchêne Katia, Cohan Jean-Pierre, Heumez Emmanuel, Oury François-Xavier, Rincent Renaud, Lafarge Stéphane, Le Gouis Jacques
UMR GDEC, INRAE, Université Clermont Auvergne, 63100, Clermont-Ferrand, France.
Biogemma, Centre de Recherche de Chappes, Route d'Ennezat CS90216, 63720, Chappes, France.
Theor Appl Genet. 2023 Oct 10;136(11):218. doi: 10.1007/s00122-023-04468-x.
Clustering 24 environments in four contrasting nitrogen stress scenarios enabled the detection of genetic regions determining tolerance to nitrogen deficiency in European elite bread wheats. Increasing the nitrogen use efficiency of wheat varieties is an important goal for breeding. However, most genetic studies of wheat grown at different nitrogen levels in the field report significant interactions with the genotype. The chromosomal regions possibly involved in these interactions are largely unknown. The objective of this study was to quantify the response of elite bread wheat cultivars to different nitrogen field stress scenarios and identify genomic regions involved in this response. For this purpose, 212 elite bread wheat varieties were grown in a multi-environment trial at different nitrogen levels. Genomic regions associated with grain yield, protein concentration and grain protein deviation responses to nitrogen deficiency were identified. Environments were clustered according to adjusted means for grain yield, yield components and grain protein concentration. Four nitrogen availability scenarios were identified: optimal condition, moderate early deficiency, severe late deficiency, and severe continuous deficiency. A large range of tolerance to nitrogen deficiency was observed among varieties, which were ranked differently in different nitrogen deficiency scenarios. The well-known negative correlation between grain yield and grain protein concentration also existed between their respective tolerance indices. Interestingly, the tolerance indices for grain yield and grain protein deviation were either null or weakly positive meaning that breeding for the two traits should be less difficult than expected. Twenty-two QTL regions were identified for the tolerance indices. By selecting associated markers, these regions may be selected separately or combined to improve the tolerance to N deficiency within a breeding programme.
在四种不同的氮胁迫情景下对24个环境进行聚类，能够检测出决定欧洲优质面包小麦耐缺氮性的遗传区域。提高小麦品种的氮利用效率是育种的一个重要目标。然而，大多数关于田间不同氮水平下种植小麦的遗传研究报告称，其与基因型存在显著的相互作用。这些相互作用中可能涉及的染色体区域在很大程度上尚不清楚。本研究的目的是量化优质面包小麦品种对不同田间氮胁迫情景的反应，并确定参与这种反应的基因组区域。为此，在多环境试验中，在不同氮水平下种植了212个优质面包小麦品种。确定了与籽粒产量、蛋白质浓度以及籽粒蛋白质偏差对缺氮反应相关的基因组区域。根据籽粒产量、产量构成因素和籽粒蛋白质浓度的调整均值对环境进行聚类。确定了四种氮有效性情景：最佳条件、中度早期缺氮、重度晚期缺氮和重度持续缺氮。在品种间观察到了对缺氮的广泛耐受性，它们在不同的缺氮情景下排名不同。籽粒产量和籽粒蛋白质浓度之间众所周知的负相关在它们各自的耐受性指标之间也存在。有趣的是，籽粒产量和籽粒蛋白质偏差的耐受性指标要么为零，要么为弱正值，这意味着针对这两个性状的育种难度应低于预期。确定了22个与耐受性指标相关的QTL区域。通过选择相关标记，这些区域可以在育种计划中单独选择或组合选择，以提高对氮缺乏的耐受性。
