Effect of seed priming and irrigation level on the yield and water productivity of French lettuce

Current study was carried out as a pot experiment to investigate the effect of different irrigation levels (100% and 70% of crop water requirement) and seed priming with salicylic acid solution (zero, 0.5 and 1 mM) on the yield and water productivity of French lettuce in the greenhouse of Zanjan University Research Farm. The experiment was done from November 2019 to February 2020 as a factorial experiment based on randomized complete blocks design with three replications. The water requirements of the control treatment crops were determined by weight method. Based on the results, means of plant fresh weight, plant head diameter, shoot dimeter, relative water content and water productivity in plants was significantly reduced in plants irrigated as 70% crop water requirement by 46%, 19%, 24%, 8% and 35% (respectively) compared to the control treatment. Seeds priming with 1 and 0.5 mM salicylic acid solution, were significantly increased means of plant fresh weight (respectively 115% and 53%), plant head diameter (respectively 23% and 10%), shoot dimeter (respectively 10% and 6%), chlorophyll content (respectively 60% and 30%), relative leaf water content (respectively 59% and 41%) and water productivity (respectively 23% and 11%) compared to the control treatment (hydropriming with distilled water). The results of the interaction of the experimental treatments showed, the maximum and minimum mean of water productivity were in 100% water requirement-1 mM SA (8.9 kg/m3) and 70% water requirement-hydropriming (2.3 kg/m3). In areas like Zanjan with limited water resources where deficit irrigation should be done to save water, seeds priming is suggested to reduce the effects of drought stress on plants.