Effect of glycine betaine and silicon on drought-stressed durum wheat (Triticum durum Desf.) plants

Water deficit is the major factor limiting durum wheat (Triticum durum Desf.) production and productivity. In this context, a first experiment was conducted to study the effect of seed priming by glycine betaine (GB) on the germination of durum wheat under water deficit stress induced by polyethylene glycol (PEG 6000). Five treatments were applied (T0: Control (0 g/l PEG, 0 mM GB); T1: 0 PEG, 50 mM GB; T2: 0 PEG, 100 mM; T3: 125 g/l PEG, 0 mM GB;T4: 125 g/l PEG, 50 mM GB;T5: 125 g/l PEG, 100 mM GB. A second experiment has focused on the evaluation of the effect of silicon (Si) foliar application on the physiological response of durum wheat to water stress in the field under semi-arid conditions. Two treatments were applied (whithout Si (Si-) and with Si (Si+)). Main results showed that durum wheat seed priming by GB improved germination and seedling growth under water deficit conditions. The highest values of germination percentage (75.83%), vigor index (434.45) and shoot length (4.45 cm) were obtained using 50 mM of GB. The foliar application of silicon improvedphysiological performance of different studied varieties.  Highest values of relative water content (57.31%), leaf area (31.56 cm2) were recorded with the application of Si. Results showed that seed priming with glycine betaine and the foliar application of silicon could be among new approaches to alleviate adverse effects of water deficit stress.