Influence of seed ageing on the germination, vigour and emergence in module trays of tomato and cucumber seeds

Seeds of tomato and cucumber were aged at 24% mc and 45 degrees C for 0, 6, 18, 21, 30, 42, 48, and 72 h before seed quality and emergence and growth in module trays were evaluated. All seeds retained high germinations with the exception of 72 h aged tomato, but germinated more slowly with mean germination time increasing from 3.86 (0 h ageing) to 6.49 days (48 h ageing) in tomato and from 1.53 (0h) to 3.27 days (72 h) in cucumber. The rate of emergence in module trays declined with increased ageing period. particularly for tomato where the mean emergence time increased from 5.71 (unaged seeds) to 9.24 days (48 h aged). Tomato seeds also produced less vigorous seedlings after ageing with significant reductions in seedling height, fresh weight and dry weight; similar but smaller changes were observed for cucumber. Despite the above evidence of ageing, the germination of seeds following the Controlled Deterioration test showed little or no decline; the significance of this observation and the implications of using aged seeds in tomato and cucumber production are discussed.