Cucurbit Genetics Cooperative Report 12:16-17 (article 6) 1989
Todd C. Wehner and Rufus R. Horton, Jr.
Department of Horticultural Science, North Carolina State University, Raleigh, NC 27695-7609
Munger reported that pistillate flowers of cucumber could be pollinated successfully up to 24 hours after they opened in the Philippines and in his New York greenhouses, but not in his New York fields (2). Lower and Edwards (1) recommended that pistillate flowers be pollinated on the morning they open, up until noon. Generally, bee activity falls off after 12 noon due to the heat in the summer of the southern U.S. cucumber production areas.
Usually, we make all of our pollinations on the morning the pistillate flowers open because it is more comfortable to work then. Also , field pollinations made in some years (where the maximum temperature was above 35°C) failed if they were made after 10 am. In July, our greenhouses reach 40°C in the afternoon, even with shading and a water-cooled ventilation system. Therefore, we doubt that delayed pollinations would be successful in the summer greenhouse. However, it is occasionally useful to pollinate pistillate flowers 12 to 24 hours after they open. We have found this to be possible, and have taken data to show the effect of the delay on seed set.
Methods. Plants of Gy 14A and ‘Marketmore 80F’ were grown in 150 mm diameter pots in the North Carolina State Univ. greenhouses at Raleigh, NC. Plants were planted in January and pollinated in February to March. Temperatures were maintained at 23 to 30°C during the day and 19 to 21°C at night. Newly-opened pistillate flowers were pollinated at 8 am, 12 noon, 4 pm and 8 am on the following day for each cultigen, setting one fruit per plant. The experiment was replicated 4 times.
Results. Generally, all of the pollination treatments were successful, and resulted in 46 to 242 seeds per fruit. There appeared to be a slight reduction in the number of seeds per fruit, and in the number of successful pollinations as pollination was delayed (Table 1). However, there were larger differences among replications than among pollination treatments, and the treatments were not significantly different.
For convenience and comfort, we intend to continue our practice of pollinating pistillate flowers on the morning they open (7 am to 12 noon). However, we will make delayed pollinations when necessary, since one would expect nearly as much success under our spring and fall greenhouse conditions.
Table 1. Effect of pollination time on seed number and fruit set of cucumbers grown in the greenhouse in Raleigh, NC.z
Time of day |
Hours after flower opening |
Cultigen |
Seeds/fruit |
No. fruits set/4 |
| 8:00 | 0 | Gy 14A | 204 | 4 |
| 8:00 | 0 | MM 80F | 126 | 4 |
| 12:00 | 4 | Gy 14A | 179 | 3 |
| 12:00 | 4 | MM 80F | 202 | 3 |
| 16:00 | 8 | Gy 14A | 148 | 4 |
| 16:00 | 8 | MM 80F | 68 | 3 |
| 8:00 | 24 | Gy 14A | 81 | 4 |
| 8:00 | 24 | MM 80F | 183 | 3 |
| LSD (5%) | – | – | NS | – |
| Mean | – | – | 148 | – |
| CV (%) | – | – | 43 | – |
z Data are means over 4 replications of 1 fruit each of 2 cultigens, Gy 14A (gynoecious pickle inbred) and Marketmore 80F (gynoecious slicer inbred).
Literature Cited
- Lower, R.L. and M.D. Edwards. 1986. Cucumber breeding. In: Breeding Vegetable Crops. AVI Publishing Co. M.J. Bassett, Ed.
- Munger, H.M. 1988. A revision on controlled pollination of cucumber. Cucurbit Genet. Coop. Rpt. 11:8.