بررسي تحمل به تنش شوري ژنوتيپ هاي گندم دوروم حاصل ازدو روش گزينش كشت درون شيشه اي و مزرعه اي در مرحله گياهچه

Study of salt stress-tolerant durum wheat genotypes derived from in Vitro and field methods at the seedling stage

Based on the results of in vitro and field experiments, eight genotypes of durum wheat [Triticum turgidum L. subsp. durum (Desf.) Husn.], comprising three salt tolerant genotypes and one salt sensitive genotype from each of which, were selected and used in this study. Genotypic responses to salt stress at seedling stage were assessed under greenhouse conditions with salinized solution culture at control 0 mM, 75 mM and 150 mM NaCl concentrations using supplemental Cat+. Plant dry weight, relative growth rate, relative water content and Ns +, K+ and accumulated in the hydroponically grown seedlings were measured at 10 and 20 days after salinity treatments. Results indicated that plant dry weight is affected significantly (P<0.01) by both genotypes and salinity levels in a way that salinity increments caused plant dry weight reduction. Relative growth rate and relative water content of genotypes were influenced with different rate under salinity levels. Increasing salinity levels during both 10 and 20 days periods caused increment of sodium concentration and reduction of potassium concentration and K+/Na+ ratio. There was a significant difference for mean of plant dry weight between in vitro tolerant genotypes (97.2 mg/plant) and field tolerant genotypes (85.6 mg/plant) under 150 mM NaCl treatment after 20 days salinity. In vitro salt tolerant genotypes (ITGs) `Dipper-6ʹ and Trion-1ʹ produced the highest dry weight, growth rate and K+INa+ ratio under salt stress conditions (150 mM NaCl) in the greenhouse. It is concluded that durum wheat genotypes, selected from in vitro saline conditions, performed successfully at the seedling stage.