Differential growth response of sunflower genotypes to NaCl stress in hydroponics

Salinity is one of the major abiotic stresses that limit the crop growth and yield, particularly in arid and semiarid regions. Among different approaches, the screening of crop genotypes for salt tolerance is important to sustain the productivity of salt affected lands. The present study was aimed to evaluate the growth performance of nine sunflower (Helianthus annus L.) genotypes grown at 15, 40, 80 and 120 mol m-3 NaCl under greenhouse conditions. Sunflower seeds were germinated in moist gravel and at two leaf stage the seedlings were transplanted to continuously aerated half-strength Hoagland's nutrient solution. The experiment was organized in completely randomized design (CRD) using four replications. Results revealed that sunflower genotypes were markedly different in biomass accumulation and ionic relations when grown at different levels of NaCl. SH-3322 and SF-187 produced maximum shoot and root length, shoot and root fresh weight as well as shoot and root dry weight at all levels of NaCI by maintaining least concentration of Na+ and higher concentration of K+ in leaf sap resulting in better K+: Na+. Genotype ICI-Hysun-33 was most sensitive. It had minimum root and shoot growth, maximum accumulation of Na+ in leaf sap and least K+: Na+ ratio. Other genotypes were arranged as QPS-1002 greater than QPS-1004 greater than QPS-1003 greater than QPS-1006 greater than QPS-1005 greater than QPS-1001 greater than ICI-Hysun-33 depending upon their salt tolerance. It was concluded that genotypes SH-3322 and SF-187 performed relatively better indicating that these genotypes had highest potential to grow under salt stress.