RELATING THE EFFECTS OF PRIMING TO GERMINATION OF UNPRIMED SEEDS

Several seed lots each of carrot, leek, and onion were primed in polye thylene glycol solutions, some of each lot were germinated immediately , and some were dried and stored for six or twelve months before germi nation. The germination parameters of primed seeds were related, using linear regression techniques, to those of unprimed seeds which had be en germinated at the same time and under the same conditions as the pr imed but undried and unstored seeds. The improvement in germination ra te, as measured by mean germination time and time to 50% germination, was more closely related to that of unprimed seeds than was germinatio n rate per se, and there were good negative relationships between impr ovements due to priming and percentage germination of unprimed seeds o n specific days. In general, relationships deteriorated with storage. Percentage germination of primed seeds was not affected by drying and storage, but seedling development was adversely affected, and the numb er of abnormal seedlings increased with storage duration. The results suggest that slow-germinating seed lots benefit more from priming than faster ones, and that the effects of priming on germination rate may be predicted from a standard test of unprimed seeds, but also that the storage potential of primed seeds is severely limited.