The supply of reliable seed has hampered the production of perilla widely grown during the winter as a leafy vegetable. Old seeds lose their germinability rather quickly while dormancy has to be broken for the newly-harvested seeds to germinate. This study was designed (1) to keep the old seed from deterioration by improving storage method, (2) to compare the lengths of dormant period, and (3) to explore the possibility of breaking dormancy by exposing the seeds to alternating temperatures. The results obtained are summarized as follows:
1. Dormancy period of Suweon 10, Haman-jairai 1 and 2, Sanchung-jairai, Chinju-jairai and Euryung-jairai was relatively short(84 days) as compared with Pusan-jairai 1 and 2 (209 days), and Chugjaso (229 days).
2. The optimum temperature for germination was 25℃ for Suweon 10, Haman-jairai 1 and 2, Sanchung-jairai and Euryung-jairai, while 10 to 20℃ for Pusan-jairai 1 and 2, Chungjaso, Kimhae 1 and 2: A lower % germination was observed at 35℃ in all low temperature germinability cultivars. When GA₃ was treated, all cultivars exhibited similar % germination at temperature of 15 to 35℃.
3. Effects of alternating temperatures on germinability were dependent on cultivars and temperature combinations. The highest of germination was observed with Pusan-jairai 2 when the seeds were incubated at 15 and 25℃ for 24 hours each for 14 days. Any temperature combinations which included 30℃ or higher exhibited poor germination. Haman-jairai 2 did less respond to alternating temperature. A lower % germination was observed with Chungjaso by alternating temperatures.
4. A relationship existed between water absorption and % germination. Suweon 10 and Hamanjairai 2 which absorbed more water, showed a higher % germination, while Pusan-jairai 2 and Chungjaso showed a lower % germination with a lower water absorption.
5. Seeds stored at room temperature did not germinate after 265 days in Chungjaso and 325 days in Pusan-jairai 2. When stored in a desiccator at room temperature for 532 days, about 90% germination was observed with Suweon 10, Haman-jairai 2 and Chinju-jairai. At room temperature for the same period their % germination was lower than 10, indicating that the seeds should be stored successfully in a desiccator. Seed stored at low temperature was also found effective to keep the seeds viable.
|