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Cucurbit Genetics Cooperative Report 16:3-4 (article 2) 1993

Turgid flowers are essential for good fruit and seed set in cucumber

R. Szegedi, I. Cserni and P. Milotay

Vegetable Crops Research Institute, 6000 Kecskemet, P.O.B. 116, Hungary

Fruit number per unit area and shape is generally a good predictor of seed cucumber yield. In short-fruited varieties most of the available ovules are fertilized under optimum conditions resulting in high seed set throughout the ovary (3). However, late setting fruits, or fruits developed under dry field conditions often remain small and deformed containing a reduced number of seeds when compared to fruits grown under optimal conditions.

Pollination is successful up to 24 hours after anthesis under glasshouse conditions (5), and a minimum two-week irrigation period is sufficient to produce viable seeds (4). However, since drip irrigation significantly affects fruit size, shape and seed yield in a large containers study (1), an experiment was designed to evaluate the influence of withholding water during pollination on fruit and seed set.

Plants of the monoecious pickling line K 4599 were trellised during the summer of 1990 under an isolating net. The planting was drip irrigated every 6 hours with fixed doses. Before pollination and after pollination irrigation was withheld in one of two rows (water stress treatment) resulting in flagging during the noon hours, while plants in the second row remained turgid (control). 30-30 flowers were hand-pollinated using two turgid male flowers on plants without previous fruit set on both rows between 12:00 and 13:00 hours. Daily temperature during pollination and the days of early fruit development ranged from 18 to 31°C. After harvest the seed number, seed weight, germination %, radicle and hypocotyl elongation (4 days at 25°C) were recorded to compare treatment and control.

Pollinated flowers set fruit on 93% of the control plants, while only 57% of the pollinations were successful on tagging plants. Fruits of the control plants were regular in shape with an average length of 17.6 cm, while 12 of the 17 fruits developed from non-turgid flowers were pear shaped with an average length of 16.3 cm. Seed number from fruit harvested from control and treatment (water withheld) plants ranged from 124 to 289 and 45 to 168 respectively. Averages calculated from 10-10 randomly chosen fruits show that fruits from water withheld plants had a significantly reduced seed number and seed weight per fruit, but withholding water did not affect thousand seed weight and germination % (Table 1). Radicle and hypocotyl elongations did not show treatment differences (data not shown).

Because pollen germinates on the stigma within 30 minutes, pollen treatment tubes reach the ovary in 12 hours and fertilize ovules enlarge within 30-36 hours (2). Our results indicate that water status of the pistillate flower during this period appears to be a significant factor in determining the quantity and quality of fruit and seed set.

Table 1. Seed yield of cucumber fruits developed from turgid and non-turgid flowers at pollination.

Pollination of

Number of fruit set

Seed number per fruit

Seed weight per fruit (g)

Thousand seed weight (g)

Germination at 25°C (%)

Turgid flowers

28

213.2

4.31

21.3

99.0

Non-turgid flowers

17

90.3

1.94

21.6

100.1

LSD 5%

-

30.8

0.48

NS

NS

NS = not significant.

Literature Cited

  1. Cserni, I., P. Milotay, A.S. Hodosy and A-ne Trefas. 1990. The effect of fertilization and water supply on cucumber seed yield and quality on different soil types. Internat. Seed Testing and Growing Conf. 25-28th June 1990. Godollo, Hungary
  2. Fuller, G.L. and A.C. Leopold. 1975. Pollination and the timing of fruit set in cucumbers. HortScience 10:617-619.
  3. Nijs, A.P.M. den and P. Milotay. 1991. Fruit and seed set in the cucumber (Cucumis sativus L.) in relation to pollen tube growth, sex type and parthenocarpy. Gartenbauwissenschaft 56.2:46-69.
  4. Wehner, T.C. nd R.R. Horton Jr. 1986, Effect of pot size on growth and flowering of cucumbers in the greenhouse. Cucurbit Genet. Coop. Rpt. 9:47-49.
  5. Wehner, T.C. and R.R. Horton Jr. 1989. Delayed pollination successful for cucumbers in North Carolina greenhouse. Cucurbit Genet Coop Rpt. 12:15-16.
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Page citation: Wehner, T.C., Cucurbit Genetics Cooperative;
Created by T.C. Wehner and T. Ng, 1 June 2005; design by C.T. Glenn;
send questions to T.C. Wehner; last revised on 6 November, 2009