Development of a Technology to Eliminate Exogenous Dormancy on Seeds, By Osmopriming, Under Laboratory Conditions.

Using a common ecotype of ‘Buffel grass’ (Cenchrus ciliaris L.) as a model, a technology is being developed based on a series of osmopriming seed treatments, in order to eliminate seed dormancy caused by seed’s florets, lemma and palea. Utilizing Polyethylene glycol 8000, KNO₃ and KCl at different concentrations for the specific solution’s osmotic potential (-2.5, -5 and -7.5 atm), and a control solution of distilled water, seed viability was first tested after trying three methodologies. The second stage of study involved the evaluation of treatment effects by a physiological quality test to the osmoprimed seeds under the best osmopriming methodology, after storage time. To define the exact time to stop immersion in each particular treatment, radicle emergence was observed using a video camera, day and night, to determine homogeneous, physiological germination of seeds. 35% of treated seeds died by lack of oxygen with this method. The second approach consisted in increasing air pressure and permitting free movement of seeds in beakers; viability did not decrease so radically, but there was still not uniform physiological germination. The third methodology applied, was based on ISTA’s recommendations to, pre-heat at 40^oC, before osmopriming. Stable air pressure, free movement of seeds, and constant temperature (25 ^oC) were also applied. These adaptations to the procedure have maintained acceptable levels of viability of the seeds.