Growth and development of asparagus bean varieties about plant density

The growth, development, and productivity of cowpeas are influenced by soil and climatic conditions, as well as cultivation techniques, particularly the optimal stand density, which requires scientific validation for the conditions of the Right-Bank Forest-Steppe of Ukraine. This research aimed to study the characteristics of growth and development of Vigna about stand density, to optimise the productivity of different varieties. Research methods included field experiments to study cultivation techniques and statistical analysis to evaluate the reliability of the results. The study, conducted between 2014 and 2016, examined the effect of standing density on two cowpea varieties (U-Cha-Kontou and Kafedralna) using four planting schemes (70×10 cm, 70×25 cm, 70×40 cm, 70×50 cm). It was found that standing density significantly affects the growth, development, phenology, and productivity of Vigna. Field germination rates ranged from 80.0% to 85.1% across the variants studied. It was noted that an increase in the sowing rate reduced the field germination of the varieties’ seeds. Differences in plant survival rates during the growing season were observed among the varieties. Extreme values of this indicator ranged from 83.6% to 87.8% for the U-Cha-Kontou variety, and from 87.7% to 91.0% for the Kafedralna variety. At a standing density of 29,000-36,000 plants per hectare, the onset of flowering in both varieties occurred later (24-27 June). Furthermore, the phases of flowering onset and fruit ripening were observed 2-3 days earlier than the control and the period from emergence to flowering lasted 46-51 days. The U-Cha-Kontou and Kafedralna varieties reached biological maturity on 27 and 22 August, respectively, at a standing density of 29,000-36,000 plants per hectare. The precocious plants were found in denser sowings of 143,000 plants per hectare, where the varieties’ growing season lasted 135-141 days. The research findings could be valuable for practical use by vegetable growers, breeders, and specialists interested in vegetable cultivation, storage, and processing