The increase of CO2 concentrations and temperatures may affect the plant development and production. This study aimed to evaluate the impact of the increased temperature and carbon dioxide concentration on the development of cowpea cultivars. The experiment was conducted in growth chambers, with control of CO2 and temperature. A completely randomized design was carried out, in a 4 x 3 x 2 factorial arrangement [cultivar x temperature (day/night) x CO2], with three replicates. The duration of the cowpea vegetative and reproductive phases was evaluated and, at the end of the experiment, the number of pods per plant, number of grains per pod, seed weight, shoot fresh and dry matter weight were quantified. Temperature affects the development of cowpea cultivars, and the temperatures of 29 ºC (day)/23 ºC (night) lead to a higher seed weight. The increase of CO2 leads to a higher number of pods and seeds and seed weight. The BRS Tapaihum cultivar presented the highest number of pods and seeds and seed weight. In addition, the temperatures of 32 ºC (day)/29 ºC (night) lead to a greater flower abortion in the BRS Pujante and BRS Tapaihum cultivars.

Rising temperature affects agricultural production, causing food insecurity. Thus, the objective of this study was to evaluate how increased temperature influences pollen viability, photosynthetic and enzymatic responses, and their consequences on the final yield of cowpea cultivars. The cultivars BRS Acauã, BRS Guariba, BRS Gurguéia, and BRS Pajeú were used, kept in growth chambers under two temperature regimes: 24.8–30.8–37.8 °C and 20–26–33 °C. The cultivars BRS Acauã, BRS Guariba, and BRS Pajeú showed prolonged flowering and greater flower abortion, at 23.58%, 34.71%, and 25.55%, respectively, under an increase of 4.8 °C in temperature. This increase also reduced the viability of BRS Acauã and BRS Pajeú pollen by 34 and 7%, respectively. Heating increased stomatal opening and transpiration but reduced chlorophyll content. The enzymatic response varied according to cultivars and temperature. Changes in photosynthetic and enzymatic activities contribute to reducing pollen viability and productivity. BRS Acauã was the most affected, with an 82% reduction in the number of seeds and a 70% reduction in production. BRS Gurguéia maintained its production, even with an increase of 4.8 °C, and can be selected as a cultivar with the potential to tolerate high temperatures as it maintained pollen viability, with less flower abortion, with the synchrony of physiological and biochemical responses and, consequently, greater production.

Cowpea planting season is crucial for high yield and should comprise the period of the year that warrants the best climatic conditions for cowpea cultivation. Thus, the objective of this study was to evaluate the influence of water availability and temperature on the performance of cowpea cultivars. A greenhouse experiment was conducted using a 4 × 2 × 5 factorial arrangement, with four replications. Factors included four levels of soil moisture (25, 50, 75, and 100% of water holding capacity), two growing seasons (mild and hot), and five cowpea cultivars (Carijó, Itaim, Pujante, Rouxinol, and Tapahium). The number of pods and seeds per plant, seed production, water use efficiency, shoot dry mass, root dry mass, and physiological parameters were evaluated. Seed production was higher during the mild season than during the hot season and increased linearly with increasing soil water availability. Photosynthetic activity and transpiration were higher during the hot season than during the mild season, with their reduction under a water availability of 25% regardless of the growing season. Total chlorophyll content decreased with excess water. Regardless of water availability, temperature was the most limiting climatic factor for cowpea performance. Cultivars Carijó, Itaim, and Tapahium exhibited a lower reduction in productive potential when grown in the hot season.

Selecting genotypes tolerant to high temperatures is an important measure for agricultural maintenance and production in climate change scenarios. Thus, this study aimed to select cowpea genotypes tolerant to increased air temperature. A total of 20 cowpea genotypes were used, cultivated under temperature regimes of 20–26–33 °C and 24.8–30.8–37.8 °C in a completely randomized experimental design under a 2 × 20 factorial scheme (temperature regimes × genotypes). The BRS Inhuma, Bico-de-Ouro-17-45, BRS Guariba, and BRS Imponente genotypes did not show significant differences in the analyzed physiological responses to the increase in air temperature. The BRS Inhuma, Bico-de-Oouro-17-19, Bico-de-Ouro-17-44, Bico-de-Ouro-17-45, BRS Guariba, and BRS Imponente genotypes showed increased temperature tolerance as thermal stress did not affect production. The Pingo-de-Ouro-17-48, MNC00-595F-27, MNC06-895E-1, and MNC09-981B-2 genotypes reduced water efficiency by −26.85, −25.19, −40.04, and −60.37%, respectively, due to the increase in temperature. The results obtained in this work represent a pre-selection of genotypes that are tolerant to high temperatures, with the BRS Inhuma, Bico-de-Ouro-17-45, BRS Guariba, and BRS Imponente genotypes indicated as tolerant to increased temperatures based on the interaction of physiological and productive responses. There is an urgent need to select cowpea genotypes tolerant to increased temperature to maintain production in climate change scenarios and ensure agricultural systems’ sustainability and food security.

Temperature is one of the climatic elements that affect most the germination process and seedling development. Thus, the objective of this study was to evaluate the germination and seedling development of cowpea cultivars under increasing temperature. The seeds of the cultivars Acauã, Carijó, Guariba, Gurguéia, Itaim, Juruá, Pajeú, Potengi, Pujante, Rouxinol, Tapahium, and Tumucumaque were kept in germination chamber at temperatures of 20, 25, 30, 35 and 40°C, with photoperiod of 12 h. Cowpea seeds have optimal germination performance and seedling development at temperatures in the range of 30.49 - 35.48°C. The cultivars presented germination percentage above 91% under 40°C, however, the seedling were abnormal. The temperature of 20°C provided germination above 96%, but with a longer period to germinate. The temperature range between 30 - 35°C favored the germination speed index, average time, and seed germination speed, with optimum temperatures varying between the cultivars. The highest rate of normal seedlings was observed at temperatures between 25 and 35°C.

In order to obtain an efficient cultivation of grain sorghum in production systems that use saline water, an adequate management becomes necessary for maximizing its production. The present study aimed to evaluate the effect of the application of leaching fractions in the saline water irrigation management on the production of sorghum varieties and on the distribution of water and salts in the soil profile, under semiarid conditions. The study was carried out in the municipality of Petrolina, semiarid region of Brazil. The experimental design was randomized blocks, with four replicates, in split-split plots; four leaching fractions (LF): 0, 5, 10, and 15% with saline water from artesian well in the plots, three varieties of grain sorghum: 1011-IPA, 2502-IPA and Ponta Negra in the subplots, and two crop cycles (1st and 2nd cut) in the sub-subplots. The evaluated variables were distribution of water and salts in the soil profile, biometric variables, fresh biomass, dry biomass, and grain yield. Application of leaching fractions of up 15% in saline water irrigation promotes better distribution of salts in the soil profile, with increments of up to 60% in the grain yield of the sorghum varieties evaluated. The production of the varieties 1011-IPA and Ponta Negra is a feasible alternative in systems irrigated with saline water with average electrical conductivity of 4.19 dS m-1, in Ultisol, under semiarid conditions.