Morphological changes in soybean cultivars subjected to apical dominance removal at phenological stages

Abstract

ABSTRACT: This study evaluated the effect of removing apical dominance at phenological stages on the agronomic traits of soybean cultivars. The experiment was conducted in the 2020/2021 growing season inthe teaching-experimental area of the Federal Institute of Education, Science and Technology of Rio Grande do Sul, Campus Ibirubá, under a randomized block design in a split-plot arrangement, with three replications. The main plots were composed of five soybean cultivars (DM53i54 IPRO, Zeus IPRO, Lanza IPRO, DM5958 IPRO, and Delta IPRO), and the subplots consisted of the phenological stages of apical dominance removal (control, V2, V4, and V6). Morphological traits were evaluated at different stages. Differences were observed between cultivars, which followed their pre-defined morphologies. Apical dominance removal reduced aspects such as the number of nodes and legumes on the main stem and the first legumeinsertion height. Cultivars developed branching mechanismsas a compensation strategy, increasing the number of legumes on the branches by up to 130%. The removal of the shoot apex can modify morphological aspects in soybean plants,but their yield tends to be maintained.

Keywords

• pinching
• branching
• yield components
• harvest index
• phytohormone