Hybrid and native sesame seeds subjected to salinity

Abstract

Sesame is a plant with great economic and social potential, being used for various purposes such as the food, pharmaceutical, medicinal industries, and more recently, as a source of renewable energy for the production of biofuel. One of the factors that most limit the productivity of this crop is salt stress. Based on this, the present work aimed to evaluate the germination and vigor of hybrid and creoles sesame seeds subjected to saline stress. The experiment was carried out at the Phytotechnics Laboratory of the Engineering and Agricultural Sciences Campus/UFAL. Two sesame cultivars were studied, BRS Anahí and Creole from the state of Sergipe. The seeds were aseptically treated by immersion in 70% alcohol for 1 minute, followed by washing in running water before being subjected to the treatments. To simulate salt stress, sodium chloride (NaCl) was used as a solute at concentrations of 0.0 (control); -0.1; -0.2; -0.3; -0.4 and -0.5 MPa. The material was placed, Biochemical Oxygen Demand (B.O.D.) germination type chamber, regulated at an alternate temperature of 20-30 °C. The experimental design used was completely randomized, with four replications of 25 seeds per treatments in a 2 x 6 factorial scheme (sesame cultivars x saline concentrations). Data were submitted to analysis of variance and polynomial regression, and the analyzes were performed using the SISVAR 5.6 software. The parameters evaluated were: water content, germination, first germination count, germination speed index, seedling length and dry mass. The results for the germination of sesame seeds submitted to salt stress showed that as the salinity levels increased there was a reduction in the percentage of germination of the sesame seeds studied, but until the concentration of -0.4 MPa they are within the standards allowed for commercialization of that culture. In the first count of germination, the Creoles sesame seeds showed the highest values, demonstrating better germination performance compared to BRS Anahí. In the germination speed index, BRS Anahí outperformed Creoles in all salt concentrations, except for the control. For seedling length, it was found that at the lowest salt concentrations both sesame varieties obtained the highest averages, with a significant reduction in length at the highest concentration (-0.5). The dry mass of the seedlings decreased as the water salinity increased, being more evident after the -0.3 MPa NaCl solution, especially for BRS Anahí. Thus, it can be concluded that salinity affects the physiological potential of sesame seeds, being more evident when at salt concentrations from -0.3 MPa. Creoles sesame seeds are less sensitive to saline stress.