Evaluation of sunflower (Helianthus annuus L.) genotypes in relation to biomass and ionic concentration under salt stress

The salt tolerance of 10 sunflower genotypes was assessed in solution culture during early growth stage in terms of their growth and ionic response to salt stress. Pre-germinated seedlings were transplanted in half strength Hoagland's nutrient solution at four salinity levels viz: 0 (control), 60, 120 and 180 mol m(-3) NaCl in three increments. The plants were harvested 30 days after imposition of stress and data regarding shoot fresh weight, root fresh weight, shoot dry weight and root dry weight were recorded. Plant leaves samples were analyzed for Na+ and K+ concentrations and K+: Na+ ratios were computed. All the growth parameters were affected by increasing the salt stress. Variations existed among genotypes for their response to NaCl stress. SF-187 and S-278 may be ranked as tolerant because these genotypes produced the maximum relative shoot fresh weight (RSFW) (81, 66 and 35% for SF-187 and 84, 65 and 35% for S-278 at 60, 120 and 180 mol m(-3) NaCl stress, respectively). The genotype Hysun-33 with 63, 35 and 17% RSFW at 60, 120 and 180 mol m(-3) NaCl stress, can be ranked as salt sensitive along with Hysun-38 which produced the RSFW at par with Hysun-33.