MODIFICATION OF GROWTH, DEVELOPMENT, AND PRODUCTIVITY OF COWPEA (VIGNA UNGUICULATA L. WALP) WITH THE APPLICATION OF CHLORMEQUAT CHLORIDE

Cowpea (Vigna unguiculata L. Walp.) is a vital legume in sub-Saharan Africa, but its productivity is limited by erratic rainfall, poor soils, pests, and excessive vegetative growth that often causes lodging, reducing flower and pod formation, and ultimately yield. This study investigated the effects of chlormequat chloride (CCC), a gibberellin biosynthesis inhibitor, on two cowpea genotypes (prostrate and erect) at four concentrations (zero, one hundred, two hundred, and three hundred ppm). Quantitative and yield-related traits were assessed five weeks after treatment and at maturity. Analysis of variance revealed significant genotypic differences in plant height, number of leaves per plant, stem girth, the number of pods per plant, number of pods per peduncle, and one hundred-seed weight, confirming genetic variability among the genotypes. CCC application significantly affected emergence percentage, plant height, number of leaves, and branches, and pod-related traits, with 200 ppm showing the most beneficial effects by reducing plant height while enhancing branching. Genotype–treatment interactions influenced several traits, although stem girth, number of days to flowering, and seed yield were not significantly affected. Mean performance across treatments and genotypes showed variation in plant height (9.98 cm to 17.54 cm), pods per plant (6.65 to 19.50), and seed yield (19.43 to 28.51 g). These findings demonstrate CCC’s potential to improve cowpea compactness and reproductive efficiency, particularly at two hundred ppm, while underscoring the need for genotype-specific applications and further multi-environment testing to enhance yield stability.