Aims Selection for optimal root system architecture (RSA) is important to ensure genetic gains in the sustainable production of wheat ( Triticum aestivum L.). Here we examine the hypothesis that past wheat breeding has led to changes in RSA and that future breeding efforts can focus directly on RSA to improve adaptation to target environments. Methods We conducted field trials using diverse wheat varieties, including modern and historic UK varieties and non-UK landraces, tested under contrasting tillage regimes (non-inversion tillage versus conventional ploughing) for two trial years or different seeding rates (standard versus high rate) for one trial year. We used field excavation, washing and measurement of root crowns (‘shovelomics’) to characterise RSA traits, including: numbers of seminal, crown and nodal roots per plant, and crown root growth angle. Results We found differences among genotypes for all root traits. Modern varieties generally had fewer roots per plant than historic varieties. On average, there were fewer crown roots and root angles were wider under shallow non-inversion tillage compared with conventional ploughing. Crown root numbers per plant also tended to be smaller at a high seeding rate compared with the standard. There were significant genotype-by-year, genotype-by-tillage and genotype-by-seeding-rate interactions for many root traits. Conclusions Smaller root systems are likely to be a result of past selection that facilitated historical yield increases by reducing below-ground competition within the crop. The effects of crop management practices on RSA depend on genotype, suggesting that future breeding could select for improved RSA traits in resource-efficient farming systems.

中文翻译：

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育种史和作物管理对小麦根系结构的影响


目标 选择最佳根系结构 (RSA) 对于确保小麦 (Triticum aestivum L.) 可持续生产的遗传收益非常重要。在这里，我们研究了这样一个假设：过去的小麦育种导致了 RSA 的变化，未来的育种工作可以直接关注 RSA，以提高对目标环境的适应能力。方法 我们使用不同的小麦品种（包括现代和历史的英国品种以及非英国地方品种）进行了田间试验，并在对比耕作方式（非反翻耕与传统耕作）下进行了两年试验或不同播种量（标准播种量与高播种量）下的测试试用一年。我们利用田间挖掘、清洗和根冠测量（“铲组学”）来表征 RSA 性状，包括：每株植物的种子根、冠根和节根的数量以及冠根生长角度。结果我们发现所有根性状的基因型之间存在差异。现代品种每株植物的根通常比历史品种少。平均而言，与常规耕作相比，浅不反翻耕的冠根更少，根角更宽。与标准相比，高播种量下每株植物的冠根数也往往较小。许多根性状存在显着的基因型与年份、基因型与耕作和基因型与播种率的相互作用。结论 较小的根系可能是过去选择的结果，通过减少作物内部的地下竞争，促进了历史产量的增加。作物管理实践对 RSA 的影响取决于基因型，这表明未来育种可以在资源节约型农业系统中选择改良的 RSA 性状。