Evaluation of Profitability of Seed Priming for Improvement Seed Germination Performance of Two Rangeland Plants (Festuca ovina and Bromus tomentellus) under Drought Conditions

The possible effects of seed priming on mitigating the effects of drought stress on germination and early seedling growth of two rangeland plants were evaluated in a laboratory research during 2015-16 growing season. The research was conducted as a 2×3×3 factorial experiment based on completely randomized design with three replications. The first factor was plant type (Festuca ovina and Bromus tomentellus), the second factor was drought stress (including 0.0, -0.3, -0.6, -0.9 and -1.2 MPa simulated with PEG6000) and the third factor was seed priming technique (including no-priming or control, hydro priming and salt priming with KNO3). Results indicated that drought stress reduced germination performances of two rangeland plants, where germination percentage, seedling dry weight, root length and stem length decreased under water deficit condition. However, B. tomentellus tolerated low-to-moderate levels of drought stress (osmotic potential of -0.3 and -0.6 MPa) but F. ovina showed a high sensitivity to drought stress where this plant did not tolerate even low levels of drought stress (-0.3 MPa). Seed priming improved germination performance of B. tomentellus under drought stress conditions but primed seeds of F. ovina had no improved germination under low availability of water. Therefore, F. ovina should experience no-stress during seed germination and seedling establishment. There was no significant (P≤0.01) difference between hydro and osmo priming for improving B. tomentellus under drought stress.However, because of low cost and easy use of hydro priming, this priming technique can be suggested for improving germination performance of B. tomentellus under low and moderate drought stress.