Similarity networks in genotypes of Vigna unguiculata (L.) Walp for green-grain production

Cowpea is one of the most significant food and nutrient sources worldwide, with importance in three primary market sectors: dry grains, seeds, and the expanding green-grain sector. This study aimed to identify phenotypic patterns for selection in Vigna unguiculata (L.) Walp genotypes for green-grain production using similarity networks and identify its morpho-agronomic variables with greater discrimination ability. The rainfed experiment was conducted in the experimental area of the horticultural sector at the Plant Science Department of the Agricultural Sciences Center of the Federal University of Ceará, Brazil, with 42 treatments. Three seeds were sown per hole, and the plants were thinned to two plants per hole, 15 days after sowing. Characterization was performed based on quantitative and qualitative variables, and the data were subjected to multivariate analysis of variance based on an augmented block design. The conjugate distance matrix for the variables was graphically represented using similarity networks to identify phenotypic patterns. The results indicated that genotypes CE-164, 207, 999, 994, 1002, and 1007 should not be used in breeding programs for green-pod production since they show genetic similarity within commercial cultivars. The variables of days to fruiting, green-pod length, green-pod width, green-pod thickness, and green-grain thickness contribute to genetic divergence and have high heritability values. Crosses between cowpea genotypes CE-165, 244, 22, 96, and 98 can yield gains in green-grain production in advanced generations.