State Plant Breeding Institute, University of Hohenheim, 70599, Stuttgart, Germany.
Institute of Plant Breeding, Seed Science and Population Genetics, University of Hohenheim, 70599, Stuttgart, Germany.
Theor Appl Genet. 2022 Mar;135(3):993-1009. doi: 10.1007/s00122-021-04012-9. Epub 2021 Dec 27.
The comparably low genotype-by-nitrogen level interaction suggests that selection in early generations can be done under high-input conditions followed by selection under different nitrogen levels to identify genotypes ideally suited for the target environment. Breeding high-yielding, nitrogen-efficient crops is of utmost importance to achieve greater agricultural sustainability. The aim of this study was to evaluate nitrogen use efficiency (NUE) of triticale, investigate long-term genetic trends and the genetic architecture, and develop strategies for NUE improvement by breeding. For this, we evaluated 450 different triticale genotypes under four nitrogen fertilization levels in multi-environment field trials for grain yield, protein content, starch content and derived indices. Analysis of temporal trends revealed that modern cultivars are better in exploiting the available nitrogen. Genome-wide association mapping revealed a complex genetic architecture with many small-effect QTL and a high level of pleiotropy for NUE-related traits, in line with phenotypic correlations. Furthermore, the effect of some QTL was dependent on the nitrogen fertilization level. High correlations of each trait between N levels and the rather low genotype-by-N-level interaction variance showed that generally the same genotypes perform well over different N levels. Nevertheless, the best performing genotype was always a different one. Thus, selection in early generations can be done under high nitrogen fertilizer conditions as these provide a stronger differentiation, but the final selection in later generations should be conducted with a nitrogen fertilization as in the target environment.
基因型与氮水平的交互作用相对较低，这表明在高投入条件下可以对早期世代进行选择，然后在不同的氮水平下进行选择，以确定最适合目标环境的基因型。培育高产、氮高效作物对于实现更大的农业可持续性至关重要。本研究旨在评估黑小麦的氮利用效率（NUE），研究长期的遗传趋势和遗传结构，并通过育种制定提高 NUE 的策略。为此，我们在多环境田间试验中评估了 450 个不同的黑小麦基因型，在四个氮施肥水平下评估了籽粒产量、蛋白质含量、淀粉含量和衍生指标。时间趋势分析表明，现代品种在利用可用氮方面表现更好。全基因组关联图谱揭示了 NUE 相关性状的遗传结构复杂，存在许多小效应 QTL 和高水平的多效性，与表型相关性一致。此外，一些 QTL 的效应取决于氮施肥水平。各性状在 N 水平之间的高相关性和基因型与 N 水平之间的交互方差相当低，表明通常相同的基因型在不同的 N 水平下表现良好。然而，表现最好的基因型总是不同的。因此，早期世代的选择可以在高氮肥料条件下进行，因为这些条件提供了更强的分化，但最终的选择应该在以后的世代中在与目标环境相同的氮施肥条件下进行。
