Morphological adjustments of soybean in response to plant equidistance and its relationship with grain yield of cultivars

Context Yield changes in soybean are influenced by edaphoclimatic and management factors, as well as by the genetics of the cultivar. The adequacy of the plant arrangement to the type of cultivar used is a fundamental point for the production performance of the crop. Aims We conducted experiments with the objective of evaluating how the equidistance between plants, represented by different combinations of row spacing and plant stand, regulates morphological traits and the agronomic performance of soybean cultivars. Methods Soybean cultivars were sown under different arrangements, represented by three plant populations and five row spacings. These arrangements were grouped into five equidistance indices, for which the higher the value was, the more balanced was the equidistance between the plants. Morphological parameters, yield components and grain yield were evaluated. Key results The distance between plants determined the competition for resources, through the regulation of the morphological and productive components of soybeans. The morphological adaptations of soybean plants that are distributed in a less equidistant way in the area, especially the increase in the size of petioles, showed a negative correlation with yield components and grain yield. Conclusions Regardless of the relative maturity group of the cultivars and the plant stand, the use of arrangements that allow better equidistance between plants is beneficial for soybean grain yield. Implications Crop establishment is a determining phase for soybean cultivation and it should be considered that arrangements that compromise the equidistance between plants can negatively affect the grain yield of the cultivars.