Relationship between Responses of Safflower Genotypes to Salinity at Germination and Vegetative Growth Stages

This study was carried out in two separate experiments in order to evaluate the responses of different safflower (Carthamus tinctorius L.) genotypes to salinity at germination and vegetative growth stages. In both experiments, thirteen safflower genotypes were investigated under non-saline and saline conditions (100 mM sodium chloride). Germination experiment was done in the seed laboratory and the experiment regarding the response of plants at vegetative stage was carried out inside a research greenhouse, Faculty of Agriculture, Isfahan University of Technology, using hydroponic culture in 2009. In this experiment, the germination rate and percentage, the root and shoot length of germinating seeds, plant height, leaf area, shoot and root dry matter were decreased under the salt treatment. The effect of salinity was not significant on shoot/root weight ratio. The interaction effects of salinity and genotype were significant on germination traits, plant height, and root dry weight. The reductions in shoot dry matter in saline compared to non saline treatment were about 32 percent for the most tolerant (A1) and about 60 percent for the least tolerant genotype (C121). Considering all traits evaluated in this study, genotypes E1431, A1, and LRV51-51 at germination stage and genotypes IL111, A1, and Arak2811 at vegetative stage were the most tolerant compared to other tested genotypes when subjected to the salinity level of 100 mM sodium chloride. Except for genotype A1, no significant relationship was found between salinity tolerance of safflower genotypes at germination and vegetative growth stages.