Effect of Seed Priming on Enhancement of Seed Germination and Seedling Growth of Annual Sainfoin (Onobrychis crista-galli (L.) Lam.) in Medium and Long-term Collections of Gene Bank

Abstract

Annual Sainfoin (<em>Onobrychis crista-galli </em>(L.) Lam.) is widely adapted to moderate and cold regions of Iran and naturally grows in pasture and rangelands used for forage in these areas. In order to study the effects of priming on seed germination and seedling growth in <em>O. crista-galli</em>, two factorial experiments were conducted based on a randomized complete design with three replications under laboratory and greenhouse conditions in Research Institute of Forests and Rangelands, Tehran, Iran in 2014-2015. Experimental factors were (A) five conservation methods including medium-term storage (active cold room 4°C for 15 years), long-term storage (basic cold room -18°C for 15 years), regenerated seeds (control) and deteriorated seeds using accelerated ageing techniques )40°C, 98% of RH for 48 and 72h). Levels of factor B were four priming treatments including Control (without priming), two osmopriming (PEG -0.4Mpa and -0.8Mpa), and hydropriming (imbibition with distilled water). Data were collected for germination percent, rate of germination, root length, shoot length, seedling length, vigor index, seedling weight and root/shoot length ratio (R/S). Result of laboratory showed higher mean values of most traits except root length in base store (-18°C). In both experiments, the highest root length was obtained in aged seeds. In greenhouse, higher values of many traits were obtained in osmopriming (PEG -0.4Mpa). In both experiment, higher mean values of many traits were obtained using hydropriming in seeds conserved in both base and active store. In the latter stores, highest root length, seedling length, R/S ratios were obtained by osmopriming (PEG -0.4Mpa and -0.8Mpa). To accelerate aging test, higher mean values of all the traits were obtained by osmopriming (PEG -0.4Mpa). It was concluded that osmopriming could be used as an effective method for the recovery of natural and artificial deteriorated seeds<strong>.</strong>