Response of safflower genotypes (Carthamus tinctorius L.) to salinity stress via germination and early seedling growth

Salinity stress is one of the most common constraints to crop productivity in the world. Therefore it is of prime necessity trying to find suitable resistant genotypes to this limiting factor. In order to study the effect of osmotic potential, on germination and early seedling growth of ten genotypes of safflower (Carthamus tinctorius L.) including KM4, KM5, KM8, KM12, KM20, KM13, KM36, KM44, KM47 and Kouse, five concentrations of NaCl (0, -0.3, -0.5 , -1 and -1.5 MPa) were treated. An experiment with factorial arrangement was conducted by using a completely randomized design with four replications in seed technology laboratory of College of Abuoraihan,University of Tehran. Germination percentage, germination rate, the length of shoot and root, length of seedling, seed vigour, germination index, mean germination time, germination rate index and root to shoot ratio measured 6 days after germination. Results of data analysis showed that there were significant difference between genotypes, stress levels and their interaction. According to the fitted logistic model, the NaCl concentration level required for 50% reduction of seed vigirity was -0.8 Mp. Cluster analysis with Wardandrsquo;s method, classified hybrids into three different groups. According to the results of this research, genotypes KM5, KM12, KM36, KM20 identified as tolerant genotypes to salinity and Kose was resistant cultivar at germination stage and early seedling growth.