Water availability and growing season temperature on the performance of sorghum cultivars

Plant yield is directly affected by the increase in air temperature and the water availability in the soil. Therefore, the objective with this study was to evaluate the physiological and productive performance of sorghum cultivars as a function of soil water availability and temperature at the cultivation time. The research was carried out at Embrapa Semi-Arid, municipality of Petrolina, Pernambuco state, Northeast region, Brazil, with planting in June 2021 and January 2022. The experiment was conducted in a randomized block design with a 2 x 6 x 4 factorial arrangement, with two growing seasons (season 1: planting in June; season 2: planting in January), six sorghum cultivars (AGRI002E, BRS 716, BRS 506, SF 15, IAC Santa Elisa and BRS Ponta Negra) and four water availability levels (25, 50, 75, and 100%), with four replications. The following variables were evaluated: total dry mass, water use efficiency, photosynthesis, stomatal conductance, transpiration and leaf temperature. The SF 15 and BRS Ponta Negra cultivars produced the highest amount of total dry mass when planted in June, with maximum temperatures ranging from 26 to 34 degrees C and 100% water availability. The AGRI002E cultivar showed higher dry mass production, photosynthesis, stomatal conductance and leaf transpiration rates among the other cultivars in season 2, with 100% of soil water retention capacity, demonstrating adaptation to the increase in temperature.