Improvement in germination behaviour of Paspalum dilatatum Poir. seeds under different pre-conditioning treatments

Poor germination and slow establishment of Paspalum dilatatum Poir. seeds hinder the inclusion of this species in cultivated pastures. Laboratory and field experiments were conducted to test the effect of different pre-sowing treatments, aimed at improving germination and field emergence, Although initial and total germination at 25 degreesC improved when seeds were mechanically scarified, the expected increase in water uptake was not observed. Alternating temperatures (20-35 degreesC) increased total germination of both control and pre-treated seeds. Osmopriming with polyethylene glycol (PEG, 20 or 30% solution) improved initial and total germination of seeds, even at 20-35 degreesC (the best germination temperature). Further experiments performed to evaluate different pre-imbibition and germination conditions on several seed sources determined it was better to osmoprime dried seeds at 20-35 degreesC. The highest seedling establishment and tillering rates in the field were achieved by pre-germinated and osmoprimed seeds. Other possible physiological effects of osmopriming Paspalum dilatatum seeds are also discussed.