An evaluation of safflower genotypes (Carthamus tinctorius L.), seed germination and seedling characters in salt stress conditions

In order to study the effect of salinity stress on germination and early seedling growth of six safflower genotypes namely KM5, KM8, KM12, KM19, KM47 and Kose by using five concentrations of NaCl (0, -0.3, -0.5, -1 and -1.5 MPa) a factorial experiment was designed using Completely Randomized Design (CRD) with three replications in Biotechnology Laboratory, Islamic Azad University-Karaj Branch. Results of ANOVA showed that salt stress adversely affected the germination percentage, germination rate, shoot length, root length, seedling length, root/shoot length ratio, seed vigour, and germination index and mean germination time of all 6 genotypes of safflower, which demonstrates high diversity among genotypes that enabled us to screen salinity tolerant cultivar. At the highest salt level (-1.5 MPa), Kose produced maximum germination percentage and germination rate of all genotypes and they were considered as relatively tolerant. Best level of NaCl concentration in root length, shoot length, seedling length and seed vigour was -0.3 MPa. Seed vigour increased with increase in osmotic potential until -0.3 MPa but decreased in -0.5 MPa. Results of cluster analysis (Ward's minimum variance method) at the highest salt level (-1.5 MPa) classified all genotypes into three group. According to the obtained results, we found that Kose is the most resistant and KM5, KM8 and KM47 are the most sensitive genotypes.