Optimal temperature for germination and seedling development in cowpea seeds

Abstract

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