The Effects of water and salt stresses on germination in two bread wheat genotypes
This study was performed to evaluating the effect of osmotic stress at the water potential levels induced by polyethylene glycol 6000 and NaCl solutions at germination stage of bread wheat genotypes (Cascogne and saisonez) at laboratory, in Iran in 2011 as factorial experiment under complete randomized design with four replications. Daily and final germination as well as germination and seedling emergence rate, and seedling fresh and dry weight were measured in the study under controlled conditions. Seedling growth was reduced by both stresses. But NaCl usually caused less damage than PEG to durum wheat seedlings, suggesting that NaCl and PEG acted through different mechanisms. Results of analysis of variance showed significant difference of all factors on all traits mostly at 0.01 percentage level. Results showed those germination rate was delayed by both solutions in both varieties, with differences between genotypes among growth stages, given that Saisonez genotype showed a higher germination rate than Cascogne genotype in NaCl. NaCl had a lesser effect on genotypes in terms of germination rate and the final germination than did PEG. This conclusively proves that the adverse effect of PEG on germination and early seedling growth was due to the osmotic effect rather than the specific ion. This difference in cultivar’s behavior according to the growth conditions is discussed. It was concluded that inhibition in germination at equivalent water potential levels of NaCl and PEG was mainly due to an osmotic effect rather than did salt toxicity. Finally Saisonez genotype showed that resistance to both NaCl and PEG stress than Cascogne genotype. So Sisonez is tolerant that Cascogne genotype at germination stage.
Key words: Bread wheat, germination, NaCl, PEG (polyethylene glycol)