Effects of Salt Stress and Temperature on Seed Germination of Sweet Sorghum (Sorghum bicolor (L.) Moench)

Salinity stress is a primary limiting environmental condition which restricts successful establishment of crops in many semiarid regions of the Mediterranean Basin. Seed germination may be significantly reduced and delayed by the decreasing rate of water absorption, when saline water is used for irrigation or when soil salinity is high. Salt stress may cause also excessive uptake of ions (Murillo-Amador et al., 2002). In the Mediterranean areas, sweet sorghum can be grown during the arid summer time, making necessary the use of irrigation water (Cosentino et al., 2002). A possibility to avoid the drought period, at least in the first stages of the growing season, could be achieved by the use of early sowings, which however may fail when thermal requirements of the species for germmation are not satisfied. Moreover, low temperature and high soil salt concentration may exert a combined adverse effect upon seed germination. In this paper, the effects of salt stress on seed germination of sweet sorghum cv. Roce at two temperatures were examined, in order to estimate the salinity threshold for germination.