Effect of Silicon Supply Methods on Durum Wheat (Triticum durum Desf.) Response to Drought Stress

Drought is a limiting factor of durum wheat production. Silicon (Si) is known by its positives effects on plant growth and development under these conditions. Thus, the current study was designed first to i) assess silicon impact on 11 durum wheat varieties performance under osmotic stress using four treatments in hydroponic trial: T1 = no stress, T2 = no stress +150 mg/l Si, T3 = osmotic stress at −0.3 Mpa and T4 = osmotic stress (−0.3 Mpa) + 150 mg/l Si. For the same objective, a pot trial was conducted with four treatments T1 = Water Stress; T2 = Water Stress + Si; T3 = Well Watered; T4 = Well Watered + Si. Results showed that in the presence of Si, the decrease of chlorophyll content, relative water content, shoot length and root length were less pronounced: 21.81%, 31.08%, 51.31% and 54.62% as compared to the control treatment (T1). Electrolyte leakage increases by 25.19% with Si addition. Also, under pot experiment, Si application improves chlorophyll content, relative water content and leaf area. Second, in order to identify the efficient method of Si supply i) seed priming ii) foliar spray iii) fertigation, another pot experiment was carried out with six treatments: T1 = Seed Priming +50% Field Capacity; T2 = Foliar Spray +50% Field Capacity; T3 = Fertigation +50% Field Capacity; T4 = Seed Priming +100% Field Capacity; T5 = Foliar Spray +100% Field Capacity; T6 = Fertigation +100% Field Capacity. The most effective Si supply method was Si foliar application.