Phenotypic plasticity in a soybean cultivar with indeterminate growth type

Abstract: The objective of this work was to evaluate how branch and stem variables contribute to grain yield in individual soybean (Glycine max) plants, cultivated at different planting densities, in a modern cultivar with indeterminate growth type. A field experiment was carried out during the 2013/2014 and 2014/2015 crop seasons, in a randomized complete block design with 12 replicates, using the cultivar NK7059 RR at four planting densities: 135, 235, 315, and 440 thousand plants per hectare. Grain yield per plant was evaluated and represented phenotypic plasticity, while the number of branches per plant, percentage of grain production in branches, and separate yield components from branches and stems were considered as the independent variables. The number of pods in branches per plant was found to be the most important variable for soybean plasticity. In addition, the number of pods per plant on stems, number of branches per plant, and the percentage of grain production in branches were also associated with plasticity. Contrastingly, the number of grains per pod and the mass of a thousand grains in the branches and stems contributed little to plasticity in 'NK7059 RR' soybean.

摘要：本研究旨在评估不同种植密度下，无限生长型现代大豆（Glycine max）品种植株的单株籽粒产量受枝条与茎秆相关变量的贡献程度。试验于2013/2014与2014/2015两个作物生长季开展，采用设置12次重复的完全随机区组设计，供试品种为NK7059 RR，设置4个种植密度梯度：每公顷13.5万、23.5万、31.5万与44.0万株。本研究以单株籽粒产量作为表型可塑性（phenotypic plasticity）的表征指标进行测定，并选取单株分枝数、枝条籽粒产量占比、以及枝条与茎秆各自的产量构成要素作为自变量。结果显示，单株枝条荚果数是影响大豆表型可塑性的最关键变量；此外，单株茎秆荚果数、单株分枝数与枝条籽粒产量占比同样与表型可塑性显著相关。与之相反，单荚粒数以及枝条与茎秆的千粒重对NK7059 RR大豆的表型可塑性贡献极小。