Effects of light and temperature on the germination and seedling vigour of Atriplex cordobensis (Gandoger et Stuckert) seeds harvested in autumn and winter

Field showing is one of the main issues to be considered in the study of the domestication of Atriplex cordobensis as a forage plant for semiarid regions. Knowledge on the factors that affect germination and seedlings vigour is essential for this stage. The purpose of this work is to evaluate the effects of temperature and light and their interaction with the harvest season on the germination and seedlings vigour of A. cordobensis. Germination percentage, G50, and dry weight of the resulting seedlings show that 8-hr photo period and 20 degrees C were optimum germination conditions. Interactions between light, temperature and harvest season were as important as the single effects of these factors. Thus, it was seen that inhibition of germination by darkness was higher at higher temperatures and greater in seeds harvested in winter than in autumn. Light appears to be necessary for the initiation of germination and temperature effect shows adaptation of this species to local temperature regimen.