Effects of Priming Techniques on Seed Germination and Early Growth Characteristics of Bromus tomentellus L. and Bromus inermis L.

Seed priming is known as a seed treatment which improves seed performance under environmental conditions. Objective of this study was to evaluate the effects of different priming treatments on seed germination behaviour of two genotypes of Bromus under laboratory conditions to find out the most effective priming treatment. Seeds were treated with the following seed-soaking media: (i) unsoaked seed (control); (ii) hydropriming with distilled water for 4, 8, 12 and 16 hours, (iii) osmopriming treatments with PEG 6000 for Bromus tomentellus were -0.6, -0.8, -1.0 and -1.2 MPa osmotic potentials with duration of 12, 24 and 36 hours and for Bromus inermis osmoticpotentials were the same as B. tomentellus but duration of priming treatments was soaking seeds for 12, 24, 36 and 48 hours. Seeds of both genotypes were placed in liquid priming media at 25C. Priming treatments significantly affected germination vigour of both genotypes. The response of both genotypes to different priming techniques approximately was similar. Osmopriming treatment (-0.6 MPa and 12 h) increased final germination percentage of B. tomentellus. Priming treatments increased coleoptile length significantly comparing to control but hydropriming for 4 h exhibited longer coleoptile than others. Higher vigour index was observed in hydropriming for 12 h but this difference was not significant with osmoprime treatment (12 h-0.6 Mpa). B. inermis produced more germinated seeds and vigourous seedlings than B. tomentellus but germination rate was higher in B. tomentellus