Effect of seed treatment on safflower (Carthamus tinctorius L.) germination under salt and drought stress conditions

The treated seeds (control, KNO3 and hydropriming) of safflower (Carthamus tinctorius L.) cultivar Koseh were evaluated at germination for tolerance to salinity (NaCl) and drought induced by PEG-6000 at the different water potentials of 0, -0.3 and -0.6 MPa. Electerical conductivity (EC) value of the NaCl solutions were 0, 6.5 and 12.7 ds.m-1. Germination index, shoot/root ratio, germination uniformity, days to 50% germination (D50) and abnormal seedlings percentage were measured. Hydropriming treatment showed an increase in germination index, shoot/root ratio and germination uniformity, while decrease days to 50% germination. Hydropriming increased germination percentage and shoot/root ratio under salinity and water stress. Treatment with KNO3 reduced abnormal seedlings percentage under salinity stress. KNO3 improved germination uniformity and germination index the low water potentials. As salinity increased, germination index and shoot/root ration were decreased, while germination uniformity, days to 50% germination and abnormal seedlings percentage were increased. As drought levels increased, shoot/root ration was decreased, while germination uniformity, days to 50% germination and abnormal seedlings percentage was increased. The results showed that hydropriming increased germination percentage. This treatment enhanced germination ratio under both stresses (salinity and drought) and non-stress conditions. While, hydropriming is simple, cheap and does not need expensive chemicals and sophisticated equipments. Therefore, could be used to improved seed performance of safflower under saline and drought stress.