Cucurbit Genetics Cooperative Report 3:43 (article 24) 1980
J.T. Puchalski and R.W. Robinson
Botanical Garden of the Polish Academy of Science, Warsaw, Poland (first author); New York State Agricultural Experiment Station, Geneva, NY 14456 (second author)
Seed dormancy is not infrequent with wild species of the Cucurbitaceae. Temperature modification (1) can overcome the dormancy of some species, and the dormancy of freshly harvested cucumber seed can be alleviated by storage and by sowing on moist paper (2). Watts (2) reported that removal of the seed coats improved germination of freshly harvested cucumber seed, and we found it helpful for dormant seed lots of other cucurbit species after prolonged storage as well. However, these treatments have been insufficient for dormant seeds of many wild species of the Cucurbitaceae.
Dormant seed of Cucumis and Cucurbita species were treated with growth regulators in an attempt to improve their germination. Germination was not stimulated by kinetin (100 ppm), fusicoccin (2 x 10-5M) or a combination of kinetin (10 ppm), ethephon (50 ppm), and gibberellic acid3 [GA3 (20 ppm)]. GA3 alone, at 100 ppm and particularly at 1000 ppm, inhibited germination of Cucumis myriocarpus at 30°C (Table 1).
Table 1. Germination of Cucumis myriocarpus seeds at 30°C after treatment with growth regulators.
Treatment |
% germination after 20 days |
| 0 | 19 |
| 100 ppm GA3 | 19 |
| 1000 ppm GA3 | 0 |
| 50 ppm GA4/7 | 25 |
| 500 ppm GA4/7 | 75 |
Treatment with GA4/7 has proven effective for seed of many genera of the Cucurbitaceae. This GA treatment should be used in conjunction with the optimum temperature for each species. Cucurbita okeechobeensis, for example, would not germinate at 20°C, even when treated with GA4/7, but did germinate at 30°C.
Literature Cited
- Heit, C., R.W. Robinson, and W. Mishanec. 1978. Dormancy of Cucumis Species. Cucurbit Genetics Coop. Rpt. 1:36-37.
- Watts, V.M. 1938. Rest period in cucumber seeds. Proc. Amer. Soc. Hort. Sci. 36:652-654.