Plant spatial arrangement affects grain production from branches and stem of soybean cultivars

ABSTRACT Phenotypic plasticity is the ability of plants to undergo changes in morphology and yield components to adapt themselves to distinct environmental conditions. The knowledge on the changes in yield components of branches and stems at varied plant spatial arrangements needs to be updated due to recent changes in soybean production system. Thus, this study aimed to evaluate the yield components of branches and stems, as well as to assess the share of these plant parts in the total grain yield of soybean cultivars with indeterminate growth type, under different spatial arrangements. The experiment was conducted during the growing seasons of 2013/2014 and 2014/2015, under a randomized complete-block design and in a4 × 3 × 2 factorial scheme with three replications. Treatments consisted of four row spacing patterns (narrow rows, twin rows, traditional row spacing, and crossed rows), three seeding rates (150, 300, and 450 thousand viable seeds∙ha–1), and two cultivars (BMX Potência RR and BRS 359 RR). Narrow rows reduce pods and grains production in branches in relation to the traditional row spacing. The number of grains per pod of stem and of branches is not altered by the changes in plant arrangement. The increase in seeding rate reduces the number of pods per plant of branches in greater magnitude than that of stems. The rise in seeding rate results in larger thousand-grain mass both of branches and of stems, but varies with the growing season.