Temperature: A major climatic determinant of cowpea production

ABSTRACT. 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.

摘要：豇豆（cowpea）种植季对高产至关重要，应选取一年中最适配豇豆种植的气候条件时段。本研究旨在探究水分有效性与温度对豇豆品种表现的影响。试验采用4×2×5完全因子组合设计开展温室研究，设置4次重复，试验因子包含4个土壤水分水平（分别为田间持水量的25%、50%、75%和100%）、2个种植季（温和季与高温季）以及5个豇豆品种（Carijó、Itaim、Pujante、Rouxinol、Tapahium）。测定指标包括单株荚果数、单株种子数、种子产量、水分利用效率、地上部干物质量、根系干物质量及生理参数。结果显示，温和季的种子产量高于高温季，且随土壤水分有效性提升呈线性增长；高温季的光合活性与蒸腾速率高于温和季，无论处于何种种植季，当水分有效性为25%时，二者均会出现下降；总叶绿素含量随土壤水分过量而降低。无论水分有效性如何，温度均是影响豇豆表现的最主要限制气候因子。Carijó、Itaim与Tapahium三个品种在高温季种植时，其生产潜力的降幅更低。