Desempenho agronômico de cultivares de feijão-caupi sob déficit hídrico na terceira safra do cerrado piauiense

Abstract

Cowpea (*Vigna unguiculata* (L.) Walp.) is of socioeconomic importance to Northeast Brazil, with water availability being a key limiting factor for productivity, particularly in third-crop cultivation in the Cerrado. This study aimed to evaluate the agronomic performance of cowpea cultivars subjected to different irrigation regimes during the third crop season in the Piauí Cerrado. The experiment was conducted in Uruçuí, Piauí, using a randomized complete block design with four replications in a split-plot arrangement, involving four cultivars (BRS Tumucumaque, BRS Pajeú, BRS Pratinha, and BRS Nova Era) and two irrigation regimes (100% and 50% of crop evapotranspiration). Plant height, pod length, number of pods per plant, 100-grain mass, and grain yield were evaluated. The results showed a significant effect of irrigation regimes on plant height, number of pods, and grain yield, with reductions in these traits observed under water deficit. The cultivars differed significantly regarding plant height, number of pods, 100-grain mass, and yield. The interaction between cultivars and irrigation regimes was significant only for 100-grain mass, indicating differential genotypic responses to water availability for this trait. Pod length did not show significant differences among treatments. It is concluded that reduced water availability compromises cowpea growth and productive performance, highlighting the importance of irrigation management for cultivation during the third crop season in the Piauí Cerrado