The evaluation of seed osmopriming and irrigation levels on growth, yield and yield component of wheat (Triticum aestivum L.)

Introduction As a major constraint limiting crop production worldwide, water deficit during plant growth period results inhibition effects on growth and yield of crops. Under drought stress, growth of crops inhibited by decline in water uptake, disturb photosynthetic path, growth retardation, metabolic disturbances oxidative damage and. Therefore, it is urgent to alleviate the adverse effects of drought stress for achieving high crop yields. Among various strategies to alleviate deleterious effects of drought stress, seed priming is thought to be an easily applied, low-cost and effective approach (Ashraf and Foolad, 2005). Seed priming include Hydropriming by water, osmopriming by ascorbic acid, potassium salts, poly ethylene glycol improved the drought resistance of different crops such as wheat (Farooq et al., 2013), lentil (Saglam et al., 2010), sunflower (Kaya et al., 2006), barley (Tabatabaei, 2013), and rice (Sun et al., 2010). Since, this study was conducted for determination growth and yield response of wheat to seed priming and different irrigation levels. Materials and mthods In order to evaluate the response of wheat to seed priming and irrigation levels, a factorial experiment based on a completely randomized block design with three replications was conducted at Research field of agriculture, University of Birjand, in 2017-2018. The treatments consisted of three levels of irrigation (I1, I2 and I3, 100, 75 and 50% of the plant water requirement, respectively) and four levels of seed priming (P1, P2, P3 and P4, 0 (control), -0.3, -0.6 and -0.9 MPa induced by PEG 6000, respectively). At the end of season growth period, plant height, tiller number, spike number, spike length, grain number per spike, 1000 seed weight, biological yield, and grain yield were measured and harvest index calculated. The traits were measured from 1 m2 of the center of each plot. Plant height, tiller number, spike number, spike length, and grain number per spike were average of ten plants. Results and discussion The results of this experiment showed that irrigation levels had a significant effect on measured traits including plant height, tiller number, spike number, spike length, grain number per spike, 1000 seed weight, biological yield, grain yield (P < 0.01). However, no significant effect was observed on harvest index. Seed priming had significant effect on plant height and spike length (P < 0.01), number of tillers, number of seeds per spike, biological yield, grain yield (P < 0.05). Interaction effects showed a significant effect on all of the traits except harvest index. The results of this study showed that the application of osmotic priming seeds -0.3, -0.6, -0.9 MPa resulted in 2.13, 2.62 and 2.15 times of seed yield at 50% water requirement treatment compared to without seed priming treatment. The results of means comparison showed that osmotic seed priming by polyethylene glycol, resulting in a pressure of -0.6 MPa, under 50% of the water requirement treatment showed the highest grain yield compensate ability. However, in 75% of water requirement treatment, pre-treatment had no significant and positive effect on grain yield, even in -0.9 MPa treatment, had a negative and significant effect on seed yield. Therefore, the application of osmotic seed priming somewhat compensated the damage caused by water shortage on grain yield under stress conditions of 50% of water requirement. While in non-stress conditions, osmotic seed priming had no positive effect on grain yield.