Evaluation of tolerance to osmotic stress of winter bread wheat genotypes using indirect physiological method

Fifteen winter bread wheat cultivars from Romania and Serbia were evaluated with regard to their tolerance to osmotic stress. Evaluation was made by applying the indirect physiological method, recognizing the growth depression seedling, cultivated in solution with increased osmotic pressure (Atm). Water deficit in most of the genotypes suppresses to a great extent the growth of roots compared to that of the shoot. The average coefficient of root growth depression was 55.77% during the moderate osmotic stress trial and 55.83 % during the strong osmotic stress trial, while with shoots the percentage was 35.76 % and 50.12 %, respectively. The average root length / shoot length ratio (R/Sh ratio) for all genotypes in the control was 1.70; in the 0.5 M and 1 M sample solution sucrose it was 1.14 and 1.55, respectively. In genotypes most tolerant to osmotic stress as Renesansa, Dragana, Izvor and Faur the root/ shoot length ratio is decreased in the highest degree. It was established there is negative regression dependence between the growth of the root/shoot and the solution with increase of osmotic pressure. The equations showed the strong limitation role of osmotic pressure for the growth of the seedling. The results of this study showed that the varieties Renesansa, Dragana, Izvor and Faur had the best ability of osmotic regulation.