Assessment of growth and development of cowpea varieties based on phenological and morphological observations

The search and selection of cowpea varieties with optimal economic characteristics is a key factor in the development of cultivation technologies to increase yields. The purpose of the study was to determine the phenological and morphological characteristics of cowpea varieties and establish the relationship between economically valuable indicators and weather conditions. The leading approaches to studying this problem are field method – to assess the growth and development of cowpea varieties; statistical – to conduct variance and correlation analysis of the assessment of morphological features and economically valuable indicators of cowpea. Five cowpea varieties were studied: Groik (Israel), Kafedralna (Ukraine), Gasson (Vietnam), American improved (USA), and U-Cha-Kontou (China). It was found that the duration of phenological phases of cowpea varieties depended on weather conditions. Varieties of cowpea were characterised by early maturation periods for the sum of effective temperatures of 192.0-207.5°C and precipitation of 30.54-31.65 mm. Earlier maturation periods were the varieties American improved, Kafedralna, Gasson with the duration of the period from germination to the beginning of harvesting ripeness of the pod – 58-62 days and the duration of the period from germination to biological ripeness of seeds – 92-94 days. For the vegetable industry, bush varieties Kafedralna and U-Cha-Kontou with a plant height of 48.5-54.9 cm were promising, which formed tender long beans with a weak parchment layer (22.8-23.6 cm). Groik and Gasson varieties proved valuable for growing seedlings due to the small light-coloured seeds with a plant height of 61.8-100.5 cm and the formation of a large number of short beans on the plant (12.8-15.6 cm). A strong relationship between morphological features and economically valuable indicators of cowpea has been established. The average bean yield had a direct strong relationship with the total number of beans per plant (r=0.93) and a strong inverse relationship with the length of the bean (r=-0.88). As the length of the beans increased, the average yield of beans and the number of beans on the plant decreased, as evidenced by a strong inverse relationship between these indicators (r=-0.93). The materials of the paper are of practical value for increasing the species diversity of vegetable crops and improving the provision of valuable food products to the population