Future grain yield (GY) improvements require the identification of beneficial traits within the context of high yield potential and not just based on the pleiotropic effect of traits such as crop height and heading date. We evaluated 1937 lines from Nested Association Mapping (NAM) population derived from 13 bi-parental varietal crosses under field conditions. We selected 493 lines with similar time to anthesis to that of the two checks used in the study (across and within each family) which reduced the range of plant height in the selected lines. Yield components were measured in these 493 lines from which 231 lines were selected by excluding lines with lowest number of grains so excluded low yielding lines. Later the subset of 231 lines were evaluated in two field experiments (2016−17, CS1 and 2017−18, CS2). Numerical and physiological components of grain yield were measured. The two-step selection maximised GY within an acceptable range of variation for height and anthesis. GY in 231 lines showed very high G × E interaction. Taking both seasons together, we selected lines from upper and lower quartile GY groups to identify stable beneficial trait combinations for improved GY. Differences in GY were explained by grain number driven by increased spike dry weight at anthesis (SDWa) and fruiting efficiency (FE). Increased GY was accompanied by sink limitation. The data points towards increases in grain number as the route towards future GY increases in wheat breeding.

未来谷物产量（GY）的提高需要在高产潜力的背景下确定有益性状，而不仅仅是基于作物高度和抽穗期等性状的多效性效应。我们评估了来自野外关联映射（NAM）种群的1937系，这些种群来自田间条件下的13个双亲杂种杂交。我们选择了与研究中所用的两次检查（在每个家庭中和每个家庭中）所用的花期相似的493个品系，从而缩短了所选品系的株高范围。在这493个品系中测量了产量成分，从中选择了231个品系，方法是排除晶粒数最少的品系，从而排除低产量品系。后来，在两个现场实验（2016-17，CS1和2017-18，CS2）中评估了231行的子集。测量了谷物产量的数值和生理成分。两步选择可以在可接受的高度和花期变化范围内最大化GY。231系的GY表现出很高的G×E相互作用。综合考虑两个季节，我们从上四分位数和下四分位数的GY组中选择品系，以确定稳定的有益性状组合，以提高GY。GY的差异由花序干重增加（SDWa）和结实效率（FE）驱动的籽粒数解释。GY增加伴有下沉受限。数据表明，随着小麦育种未来GY途径的增加，谷物数量将增加。综合考虑两个季节，我们从上四分位数和下四分位数的GY组中选择品系，以确定稳定的有益性状组合，以提高GY。GY的差异是由花序干花重增加（SDWa）和结实效率（FE）驱动的粒数解释的。GY增加伴有下沉受限。数据表明，随着小麦育种未来GY途径的增加，谷物数量将增加。综合考虑两个季节，我们从上四分位数和下四分位数的GY组中选择品系，以确定稳定的有益性状组合，以提高GY。GY的差异是由花序干花重增加（SDWa）和结实效率（FE）驱动的粒数解释的。GY增加伴有下沉受限。数据表明，随着小麦育种未来GY途径的增加，谷物数量将增加。