Genes of photoperiod sensitivity and early maturity E1-E4: dynamics of soybean growth in different daylength conditions

Background. Morphometric indicators are crucial for evaluating the development and productivity of soybeans. They are influenced by genetic and environmental factors. The use of nearly isogenic soybean lines is a convenient model for determining the impact of early maturity genes and daylength on growth indicators. The aim of this study was to determine the influence of different daylengths and early maturity genes on soybean morphometric indicators under conditions of the temperate zone (at the latitude of Kharkiv – 50° N). Materials and Methods. The study involved nearly isogenic soybean lines of the “Clark” cultivar with varying sensitivity to daylength. The research covers the results of field experiments over three seasons using different soybean lines. After reaching the V3 stage, some plants were subjected to short-day conditions for 14 days. Morphological indicators of ten plants per experimental variant were determined: plant height, dry weight, leaf number, and leaf surface area of soybean plants. Morphometric measurements were taken on the day of the beginning of different daylength treatments and on days 7, 14 and 21. The study results are presented as the mean values of the investigated parameters (plant height, dry weight, number of leaves and leaf surface area of soybean plants). Results. It was shown that under long-day conditions, dominant alleles of the E1 and E3 genes increased the dry weight of plants, while the dominant allele E2 increased plant height. The dominant allele E4 had no significant effect on plant height and weight indicators of soybean plants. Plants with dominant alleles of genes E1-E4 under long-day conditions had smaller leaf area compared to lines with recessive alleles of these genes. Conclusions. The obtained results on the relationships between genetic and environmental factors in influencing soybean plant height, weight, and leaf area can be useful in improving soybean yield and selecting cultivars that will be productive in high latitude conditions.