Cucurbit Genetics Cooperative Report 3:25 (article 14) 1980
Pollen Receptivity of Different Areas of the Stigma in
Cucumber
R.W. Robinson and D.F. Heffernan
New York State Agricultural
Experiment Station, Geneva, NY 14456
Pollen was placed with a dissecting needle on different
areas of 'Wisconsin SMR 18' stigmas to determine the area
of greatest receptivity. Five different areas of the stigma
were pollinated including (1) the apical tip of each of
the three stigmatic lobes, (2) the upper center of the stigma,
at the juncture of the three lobes, (3) the upper portion
of the outer side of each stigmatic lobe, (4) the lower
half of the side of each lobe, and (5) all external areas
of a single stigmatic lobe.
Each area of the stigma was receptive to pollination. Each
treatment resulted in fruit set and the formation of viable
seed (Table 1). However, many of the fruit had poor seed
development at the peduncle end of the fruit, probably due
to the small amount of pollen applied. Better seed formation
occurred when larger amounts of pollen were applied; 106
seeds per fruit resulted when a copious quantity of pollen
was applied by hand to all parts of the stigma and open
pollination resulted in 177 seeds per fruit, in contrast
to 17 to 62 seed per fruit when smaller amounts of pollen
were applied for the different treatments.
In-experienced pollinators sometimes apply a small amount
of pollen to only the easily accessible apical tips of the
stigmatic lobes, but this treatment resulted in the lowest
fruit set. To obtain maximum seed production, it is advisable
to apply a generous amount of pollen to the entire surface
of the stigma.
Pollen tubes may develop laterally as well as basipetally.
When pollen was placed on only one of the stigmatic lobes,
the preponderance of seeds that developed were in the fruit
locule directly below the stigmatic lobe that was pollinated.
However, seeds also developed in the other fruit locules,
indicating lateral growth of the pollen tubes.
Table 1. Effect of pollen placement on fruit set and seed
formation.
Stigmatic area pollinated |
No. of pollinations |
% fruit set |
Seeds per fruit |
Seeds per pollination |
Tips |
11 |
36 |
62 |
23 |
Center |
11 |
82 |
17 |
14 |
Upper half of side |
9 |
56 |
27 |
15 |
Lower half of side |
11 |
46 |
44 |
18 |
Single lobe |
11 |
82 |
44 |
36 |
