Development of soybean yield and seed productivity elements depending on the variety

In the context of global climate change and the food crisis, soybeans (Glycine max) requires optimisation of the genetic potential to ensure stable and high productivity through the identification of genotypes with high adaptability in specific soil and climatic conditions, in particular the forest-steppe of Ukraine. The purpose of the study was to investigate the influence of varietal characteristics on the development of key morphological and productive features of soybeans and assess its compensatory ability during two years of research. The study was conducted during 2024-2025 using field, biometric, and correlation analyses to estimate plant height, the number of pods per plant, the number of branches, and the weight of 1,000 seeds. A high varietal dependence of all studied traits has been established, which emphasises the decisive importance of the genotype. A strong negative correlation was found between plant height and the number of pods per plant (r = -0.897), which indicates a negative effect of excessive vegetative growth on generative productivity due to a violation of the balance of sources and drains. It was confirmed that the intensity of branching had only a weak effect on crop development. The mechanism of compensatory ability during the years of research (phenotypic plasticity) was revealed: a decrease in the number of pods under unfavourable conditions led to a compensatory increase in the weight of 1,000 seeds. Among the samples studied, the varieties ‘ES Mentor’, ‘Antracit’ and ‘Muza’ had the most balanced combination of high seed productivity, seed quality, and satisfactory attachment height of the lower pods. The results of the study provide important information for optimising the varietal composition in the region, and also serve as a basis for breeding work aimed at adapting soybeans and improving the efficiency of fruit setting in the forest-steppe zone.