Cucurbit Genetics Cooperative Report 12:16-17 (article 6) 1989
Delayed Pollination Successful for Cucumbers in North
Carolina Greenhouse
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°F) 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 |
|
Gy 14A |
|
|
8:00 |
|
MM 80F |
|
|
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.
