Physiological Quality of Cowpea Beans (Vigna unguiculata L.) Seeds in the Function of Cultivars and Planting Times

Germination and vigour evaluation of improved cultivars and creole of cowpea bean seeds as a function of different planting seasons. A completely randomized design in a factorial scheme, with six treatments and two planting periods, with four replications, each repetition with 25 seeds. The treatments consisted of six cowpea bean (Vigna unguiculata L.) cultivars, and two improved (BRS Tumucumaque, BRS Guariba) and four creoles, (Governor, Passagem, Chico Joaquim and Espírito Santo). The experiment place and timing was carried out under greenhouse on a riparian zone of the Federal Rural Semi-Arid University (UFERSA), located in the municipality of Mossoró-RN, Brazil. The first sowing season comprised the period from April 3 to April 18, 2017, and the second one from January 15 to 30, 2018. The sowing was done in plastic trays. Was used the sand washed and sterilized as a substrate. The trays were kept in a greenhouse at room temperature. Two irrigations were realized daily. In order to avoid the local effect, the trays were changed position each day. The evaluated characteristics were: Germination percentage, emergence speed index, seedling height, leaf number, root length, stem diameter, fresh and dry mass of seedlings. Creole cultivars showed superior quality to those improved in the second season. In the first season, the cultivars BRS Guariba and BRS Tumucumaque were the most outstanding. It was concluded that the physiological quality of cowpea beans is directly influenced by the cultivars and the planting season, as well as by the interaction of these two factors.