No abstract

This research was conducted to investigate the efficacy of charcoal and ash in maintaining the quality of lettuce, cabbage, onion, pepper and carrot seeds during storage. The seeds were stored over charcoal and ash at a seed/material ratio of 1:1 and stored at room temperature (20°C) and at 35°C for 24 months. The control seeds were dried to between 5-6% seed moisture content and stored in hermetic packets at -20°C. Samples were collected from storage after 6, 12, 18, and 24 months and subjected to a germination test and ageing test at 45°C for 72 hours using 72% saturated sodium chloride (NaCl) solution. There was no difference between the seed viability for the controls and treatments after 6-12 months at 20 and 35°C between the two storage methods. However, seed quality declined at 18 months and 24 months. This was seen in lettuce, onion and carrot seeds more than pepper and cabbage at both storage temperatures. Similarly, seed vigour also reduced with extended storage to 18 and 24 months. Results showed ash and charcoal can be used to maintain seed quality over 12 months even at 35°C.

This work was carried out on twenty onion seed lots to test changes in seed quality during storage at-20°C after priming treatment. Seeds were matric primed at 20°C by mixing seed, vermiculite and water at the ratio of 2:1:3 for 48 hours at 15°C and subsequently dried to 7% seed moisture content. They were then hermetically stored at-20°C over 60 days, and samples were taken after 0 (unstored), 15, 30 and 60 days. Seed germination percentages (20°C, 12 days) and mean germination times were determined. Results indicated that mean germination percentages of the control and primed but not stored seed lots were 80 and 85% respectively. Germination percentages after 15 and 30 days at-20°C remained as high as those of primed and unstored seeds, which were 87%. However, by 60 days after storage, primed seed germination percentages were reduced to 82%, which was non-significant compared to the control. The fastest germination-the lowest mean germination times-were also recorded as 3.64 days after 30 days of storage (p<0.05). Results indicated that the benefit obtained from priming may remain in onion seeds for about 30 days after storage at-20°C. Extended storage of up to 60 days can reduce the advantage that is obtained from priming. Storage of primed onion seeds at freezing temperatures can be an alternative method to reduce seed ageing and to maintain high seed quality longer for a certain period.