Roots strongly influence the growth and yield of field crops. We characterized root morphological traits of 10 winter wheat varieties in order to determine the extent they were influenced by the environments and impacted grain yield under two irrigation regimes at Bushland (a cooler, drier site with clay loam soil) and Uvalde (a warmer, wetter site with clay soil) in Texas, USA, from 2015 to 2017. Major root traits, including root diameter, specific root length (SRL), root surface area (SSA), tissue mass density (TMD), root length density (RLD), and root weight density, were measured and related to one another and to grain yield. RLD of wheat decreased but SRL and SSA increased with soil depth. Irrigation was second to environment in affecting root traits. Compared with Uvalde, the environment of Bushland promoted deeper root growth, higher TMD, but reduced SRL and SSA. Water deficit inhibited RLD and root: shoot ratio at Bushland, but moderately promoted them at Uvalde. Both SRL and RLD were positively associated with grain yield, with the former relation stronger under drought. The dichotomy of “conservative” versus “acquisitive” root strategy partially explained the variations of root traits of winter wheat in contrasting environments.

中文翻译：

---

不同环境下冬小麦根系形态特征

根强烈影响大田作物的生长和单产。我们对10个冬小麦品种的根系形态特征进行了表征，以确定在2种灌溉制度下，布什兰德（较冷，较干燥的土地上有粘土壤土）和乌瓦尔德（较温暖，较湿）两种环境下它们受环境和谷物产量的影响美国得克萨斯州，2015年至2017年。主要的根性状，包括根直径，比根长（SRL），根表面积（SSA），组织质量密度（TMD），根长密度（RLD） ，和根重密度，被测量并与彼此和谷物产量相关。小麦的RLD随土壤深度而降低，但SRL和SSA随土壤深度而增加。在影响根系性状方面，灌溉仅次于环境。与Uvalde相比，Bushland的环境促进了更深的根系生长，更高的TMD，但减少了SRL和SSA。缺水抑制了布什兰州的RLD和根：茎比，但在乌瓦尔德则适度地促进了它们的生长。SRL和RLD都与籽粒产量成正相关，而前者在干旱条件下则更强。“保守”与“获取”根策略的二分法部分地解释了在不同环境下冬小麦根性状的变化。