Response of Sunflower Genotypes to Salinity Stress Under Laboratory Conditions

Sunflower (Helianthus annuus L.) is an essential oilseed crop known for its adaptability to harsh environments including drought. However, salinity stress, affecting over 20% of global agricultural land, poses a serious threat to its productivity. This study evaluated the response of 17 sunflower genotypes under salinity stress (200 mM NaCl) and optimum (0 mM NaCl) conditions in the laboratory. The experiment was arranged in a completely randomized design with three replications and was validated through a second experimental run. Measured parameters included germination percentage and speed, root and shoot length, biomass, and water content. Stress tolerance indices (STIs) for germination, seedling length, and biomass were calculated. Combined ANOVA showed that genotype and environment interactions significantly (p < 0.001) affected all measured traits. Salinity stress significantly reduced germination, seedling growth, and biomass across genotypes, with some experiencing complete germination inhibition. Genotypes 9, 14, 16, and 17 consistently maintained higher germination, seedling length, and biomass under stress, with high STIs, indicating tolerance to salinity stress during the early growth stages. These results identified genotypes 9, 14, 16, and 17 as promising candidates for breeding programs aimed at enhancing salinity tolerance, offering sustainable solutions for the utilization of saline soils and for enhancing food security. Future research should focus on the field-based validation of these genotypic responses.