Cucurbit Genetics Cooperative Report 1:8-9 (article 6) 1978
R. L. Lower, D. M. Pharr and E. K. Horst
North Carolina State University, Raleigh, NC 27650
Research by Beyer (1) and by De Ponti and Kho (2) discuss the effects of silver nitrate alone, and in combination with gibberellic acid, respectively, on sex expression of cucumber. Preliminary observations in the field in North Carolina indicate that silver nitrate will induce staminate flowers on the gynoecious inbred, ‘Gy 14’, however concentrations greater than 250 ppm resulted in severe phytotoxicity in a fall planting. A more detailed experiment was conducted in the greenhouse during the winter of 1977-1978. Five treatments were used and data collected on staminate flower no., plant height, fruit size, and shape (Table 1).
Table 1. Effects of silver nitrate and gibberellic acid on sex-expression and growth of gynoecious cucumber, ‘Gy 14’.
Treatment ¹
|
Plant height (cm) |
Nodes with staminate flowers |
Fruit length (cm) |
Fruit diameter (cm) |
Fruit weight (g) |
| 1. AgNo3 50ppm (3x) | 53.4 | 3 | 17.5 | 7.6 | 613 |
| 2. AgNo3 250ppm (1x) | 61.2 | 9 | 16.3 | 7.4 | 464 |
| 3. GA 4/7 50ppm (3x) | 115.6 | 16 | 17.8 | 7.6 | 596 |
| 4. Combination of 1 and 3 | 114.2 | 15 | 18.3 | 7.9 | 635 |
| 5. Control | 42.9 | <1 | 15.0 | 6.6 | 385 |
| LSD .05 | 12.3 | 1.5 | 1.8 | NS | 147 |
¹ Single treatments were made at the first true leaf stage. Additional treatments were made 5 and 10 days later.
Plant height was measured thirty days after the initial treatment and was greatest for the two treatments involving GA. The silver nitrate treatments were not different but were different from the GA treatments. The control was shorter than all treatments except, the low rate of silver nitrate.
The GA treatments gave a larger number of staminate nodes than the other treatments and the 250 ppm silver nitrate was more effective than the lower rate of silver nitrate. There was no difference between GA alone or in combination with silver nitrate. Generally, staminate flowers were found at consecutive nodes until pistillate flowers appeared. The presence of both staminate and pistillate flowers at the same node was more common at 50 ppm silver nitrate treatment than at any other treatment.
Fruit from the control plants were shorter than those treated with GA and the lower rate of silver nitrate. Fruit diameter was not affected by treatment. Fruit of the control were smaller than those in all treatments except the high rate of silver nitrate.
Seed yields were inconsistent and no trends or differences were measured. No measurements of pollen viability or amount were made.
There was no evidence of phytotoxicity from any of the treatments.
Literature Cited
- Beyer, E. Jr. 1976. Silver: a potent antiethylene agent in cucumber and tomato. HortScience 11: 195-196.
- De Ponti, O. M. B., and Y. O. Kho. 1977. Induktie van mannelijke bloei in konkommer en augurk door zilvernitrast: een alternatief voor gibberellzauur? Zaadbelangen 31: 53-57.