Avaliação da tolerância ao déficit hídrico em feijão de corda Vigna unguiculata (L.)Walp.1832 sob condições simuladas no extremo sul do Piauí

Abstract

Brazil faces challenges in the cultivation of crops sensitive to climate change, such as cowpea (Vigna unguiculata (L.) Walp.), especially due to abiotic stresses such as water deficit. This crop, widely grown in semi-arid regions, has nutritional and economic importance, in addition to its ability to adapt to different production systems. In this context, the present study aimed to analyze the effects of water stress on the productivity and development of cowpea. The experiment was conducted under field conditions, with the application of water volumes ranging from 100 to 1000 mL per plant, in three-day cycles, including a control group and another subjected to water stress corresponding to 50% of the control irrigation level. The evaluated parameters were plant height, stem length, pod width, number of locules per pod, 100-grain weight, and total grain weight. Plant height ranged from 12 to 30 cm in the control group and from 13 to 27 cm under water stress. Stem length varied between 20 and 35 cm in the control and between 22 and 40 cm in the water-deficit treatment. Pod length ranged from 11.8 to 19.8 cm in the control and from 6.6 to 21 cm in the stressed treatment, while pod width varied from 1.0 to 2.5 cm in the control and from 1.3 to 2.5 cm under stress. The total number of pods was 41 in the control and 37 under water stress. The 100-grain weight was 39.99 g in the control and 33.34 g in the water-deficit treatment, whereas total grain weight was 64.06 g in the control and 36.83 g under stress. Overall, no statistically significant effect of water stress was observed for most of the evaluated variables, except for the number of locules per pod, which ranged from 6 to 17 in the control and from 4 to 15 under water deficit. It is concluded that the reduction in irrigation depth did not significantly compromise most of the analyzed parameters, suggesting a certain tolerance of the crop to the applied stress level