Water deficit limits growth and yield of cowpea cultivars

ABSTRACT Irrigation management is essential for applying the required amount of water to crops. This study evaluated the growth and yield of cowpea cultivars as a function of water regime. The experiment was conducted in Teresina, Piauí State, Brazil, from July to September 2022. The experimental design comprised a randomized block in a split-plot scheme with four replicates. The treatments comprised five water regimes (133.80, 191.70, 249.00, 303.00, and 357.00 mm per cycle) and two cowpea cultivars (BRS Inhuma and BRS Olho Negro). Physiological characteristics, growth, and yield were also evaluated. Decreasing water regimes restricted the relative water content of the leaves, relative chlorophyll index, leaf area index, dry matter accumulation, number and size of pods, and cultivar yield. BRS Inhuma showed greater growth, dry matter accumulation, and yield but was more sensitive to decreasing water regimes. Water regimes of 311.00 and 332.08 mm per cycle maximized the yield of BRS Inhuma and BRS Olho Negro, respectively. BRS Olho Negro was more tolerant to growing conditions under water-deficit conditions, indicating that there were genetic variations among the cultivars. Therefore, identifying cowpea cultivars that are more tolerant to water deficit is fundamental to ensuring high yields in irrigated areas.