Layana Alves Do Nascimento

Cowpea ( Vigna unguiculata (L.) Walp.) is a crop of major importance in semiarid regions, where powdery mildew can significantly reduce productivity. This study evaluated powdery mildew severity in four cowpea cultivars grown under monocropping and intercropping with two biomass sorghum ( Sorghum bicolor (L.) Moench) across two planting seasons (June and December 2021) under semiarid conditions. The experiment was conducted in a randomized complete block design arranged in a 12 × 2 factorial scheme with three replications, and disease severity was assessed at the R9 stage by means of the percentage of leaf area affected. Planting season significantly affected disease severity, and a significant season × treatment interaction was detected, indicating that the effects of cultivar and cropping system depended on planting season. Disease severity was higher in the June planting, whereas December planting reduced severity by 69.60%. Intercropping reduced disease severity for most cultivars during the June planting. Monocropping systems showed higher grain yield due to greater plant density, averaging 2.11 and 2.29 t ha ^{− 1} in June and December planting, respectively, while intercropping averaged 1.15 and 1.22 t ha ^{− 1} . However, intercropped cowpea maintained stable productivity per plant despite a 50% reduction in plant density. These results demonstrate that adjusting planting date and adopting intercropping with adapted cultivars can simultaneously reduce powdery mildew severity and maintain productive stability in semiarid cowpea systems.

Global warming poses a threat to food security, particularly for essential crops like cowpea, which exhibits sensitivity to heat stress. This study aimed to evaluate the morpho-agronomic diversity of cowpea genotypes under different daily temperature regimes. The experiment was conducted in growth chambers, and biometric and productive traits were measured to quantify genetic divergence using Mahalanobis distance and UPGMA clustering. Temperature increases markedly altered trait expression. Under the 20–26–33 °C regime, 100-grain weight, leaf dry weight, pod weight, and stem dry weight accounted for 54.44% of the total variation. Under the higher temperature regime (24.8–30.8–37.8 °C), number of pods, plant height, stem fresh weight, and leaf dry weight explained 67.27% of the diversity, evidencing the impact of heat stress on vegetative and productive traits. Cluster analysis identified five distinct groups, confirming genetic variability and temperature-dependent dissimilarity patterns. Genotypes Bico de Ouro 17-53, Bico de Ouro 17-33 and BRS Tumucumaque maintained higher grain number and grain weight under elevated temperatures, whereas others showed yield reductions of up to 65%. These findings demonstrate exploitable genetic variability for heat tolerance in cowpea and support the use of morpho-agronomic traits as effective criteria for selecting genotypes adapted to warmer environments.

Global projections indicate that the demand for fresh water, energy, and food will increase significantly in the coming decades under the pressure of population growth, economic development, climate change, and other factors. Faced with this, technologies that promote sustainable development through the use of clean energy will be imperative. That way, this study aimed at evaluating the productive performance of biomass sorghum and cowpea cultivars in different cropping systems and planting seasons. The experiment was conducted at the Caatinga Experimental Field at Embrapa Semiarid, Petrolina—PE. Four cowpea (BRS Itaim, BRS Gurguéia, BRS Guariba, and BRS Carijó) and two biomass sorghum cultivars (BRS 716 and AGRI-002E) were used in intercropping and monoculture systems. The cultivars were sown during two different seasons: June (season 1—winter) and December (season 2—summer) of 2021. The biometric and productive parameters and land equivalent ratios (LERs) of sorghum and cowpea were evaluated. The data were subjected to multivariate analysis. The productive performance of biomass sorghum cultivars Agri-002E and BRS 716 was higher when planted in December, with an increase of 37% due to the planting season. Cowpea productivity was not influenced by sowing seasons or the cultivation system. Based on the calculation of efficient land use, the intercropping between biomass sorghum cultivar BRS 716 and cowpea cultivars BRS Gurguéia, BRS Guariba, and BRS Carijó was advantageous when compared to monocultures planted in the hottest season. This study showed the importance of cultivar selection, the planting time, and land use efficiency in intercropping systems.