Emergence and initial growth of cowpea varieties at different temperatures

Resumo

Brazil is the largest producer and consumer of beans in the world; however, the prospect of climate change could affect this production. Among these changes, the incidence of rising temperatures can directly affect the crop cycle, influencing biochemical processes that occur during seed germination and seedling emergence. The objective of this work was to determine the optimum temperature level for the emergence and initial growth of three varieties of cowpea. The experiment was conducted in a laboratory linked to the Federal University of the São Francisco Valley, Juazeiro Campus, state of Bahia, with a completely randomized design (DIC), in a 6x3 factorial scheme, with six treatments at different temperature levels: 20, 25, 30, 35, 40 and 45 °C; and three varieties of cowpea: BRS Pajeú, BRS Nova Era and BRS Pujante. The following variables were assessed: speed index, average time, relative frequency and percentage of emergence; stem length and diameter; accumulation of fresh and dry biomass in the stem, leaf and root. The ideal temperature range found for the emergence and initial growth of the cowpea varieties BRS Pajeú ranged from 27 to 32 ºC, for BRS Nova Era between 30 and 41 ºC and for BRS Pujante between 29 and 35 ºC. As the BRS Nova Era variety performs better in high temperature conditions, it could be an alternative for growing beans in the face of climate change.