Qualidade fisiológica de sementes de gergelim BRS seda submetidas a estresse hídrico

Abstract

Sesame (Sesamum indicum L.) is an oleaginous plant cultivated in rainfed conditions and represents an income alternative for producers in the Brazilian Northeast. However, the physiological quality of seeds is one of the main factors responsible for success in the field and contributes significantly to achieving high levels of productivity. Thus, this study aimed to evaluate the physiological quality of BRS Seda sesame seeds subjected to water stress at different temperatures. The experiment was carried out at the Seed Analysis Laboratory, at the Department of Plant Science and Environmental Sciences at the Center for Agricultural Sciences, at the Universidade Federal da Paraíba. The experimental design used was completely randomized, in a 2 x 5 factorial scheme, with two temperatures (25 and 30 °C) and five osmotic potentials (0; -0.2; -0.4; -0.6 and - 0.8 MPa). The evaluations were: water content, germination test, first count, speed index and average time of germination, percentage of hard and dead seeds, abnormal seedlings, length and dry mass of seedlings. Temperature and water stress significantly influence the physiological quality of sesame seeds. The highest percentage of dead and hard S. indicum seeds were obtained when the seeds were submitted to 30 °C. The reduction of osmotic potential negatively influences the vigor of S. indicum seeds at the evaluated temperatures. The temperature of 25 °C favors the germination performance in less restrictive water potentials (-0.2 MPa).