PROLONGED AERATED HYDRATION FOR IMPROVEMENT OF SEED QUALITY IN BRASSICA-OLERACEA L

Seeds of cauliflower cv. Hipop and Brussels sprouts cv. Asmer Aries we re aged at 20% moisture content for 24 h; all seeds retained a germina tion of over 70% after ageing although the mean germination time incre ased. Prolonged aerated hydration for up to 32 h at 20 degrees C follo wed by drying resulted in improved performance of both unaged and aged cauliflower seeds and aged Brussels sprouts. Thus, all seed showed re ductions in the mean germination time to the extent that after 32 h hy dration the aged cauliflower seeds performed as well as high quality u naged seed. The improvement of aged seeds was also revealed by an incr ease in germination after the controlled deterioration test following up to 24 h (cauliflower) or 32 h (Brussels sprouts) aerated hydration. This increase was indicative of a decrease in the extent of deteriora tion present after aerated hydration. Deleterious effects of prolonged hydration were observed in Brussels sprouts after 32 h although these may be explained by desiccation injury after treatment since radicle emergence had occurred during hydration. The improvements in seed perf ormance may be explained by the activation of metabolic repair occurri ng during the early part of the hydration period thereby reducing the extent of deterioration that has been sustained during ageing, with fu rther improvements due to the advancement of the germination process.