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Plants produce their own hormones that influence cell division in stems, leaves and fruits. Hybrid grape varieties often have sterile pollen as a result of selection in inflorescences. They require additional pollination in order for full-fledged bunches to mature. One of the most effective means of increasing yields for unisexual grapes is gibberellin.
What is Gibberellin?
Gibberellin is a hormone obtained microbiologically from a fungus. The drug is an analogue of the natural phytohormone produced by the grape seed after the formation of the ovary. Artificial gibberellin is not an alternative to natural pollination. The functional purpose of the drug is to stimulate berry growth.
If the bud is not pollinated during the flowering of the vine, no seed will form in the ovary. As a result, the berries do not grow and do not gain weight, which leads to the dropping of the ovaries, the peeling of fruits in the bunch. Such situations are typical for seedless varieties and homosexual hybrid forms.
The drug was developed more than 20 years ago for the treatment of raisins vineyards. Later, gibberellin was used on grapes with functionally female flowers. The hormone, getting on the skin of the ovary, is absorbed into the berry and causes an increased metabolism without the formation of seeds.
When processing the vines in the flowering stage, the substance enters the stamens, further exerting a positive effect on the mass and size of the berries, the appearance of the bunch, also without the formation of seeds. Large grapes in bunches without seeds (not raisins) are the result of processing the vine with gibberellin.
Advantages and disadvantages
The use of gibberellin increases the productivity of unisexual grape vines and raisins by 1.5-2 times. The use of a phytostimulant is especially important in unfavorable weather conditions for pollination: in cloudy, cool, rainy weather.
Other advantages of using a phytohormonal agent:
- improving the presentation of grape bunches;
- acceleration of ripening of berries by 5-7 days;
- increased sugar content;
- improvement of keeping quality.
The drug is not toxic to humans, animals and insects. The vineyard does not require hand and respiratory protection.
The disadvantage of the drug is the lack of an exact dosage for each variety. For this reason, vines of different varieties should not be sprayed with phytohormone of the same concentration. To obtain an increase in the productivity of the vine, an exact dosage is required, determined empirically.
The treatment should be carried out in the evening to prolong the absorption of the hormone into the membranes of flowers and ovaries. For the complete assimilation of the stimulant, plant tissues need 6-8 hours. Rainy weather during this period reduces the treatment effect. The procedure must be repeated.
Instructions for using the preparation for grapes
Gibberellin comes in the form of a white powder, packed in plastic bags. The weight of one sachet is 300 milligrams. The average rate for a unisexual variety is 25-30 milliliters per liter. Seedless varieties without seeds - the rate is doubled / tripled.
Zarechny Maxim Valerievich
Agronomist with 12 years of experience. Our best summer cottage expert.
The substance is insoluble in water. An alcohol solution is preliminarily prepared: for 300 milligrams - 10 milliliters of alcohol. The dosage is carried out using a syringe: 1 ml of solution = 30 ml of gibberellin. The finished solution is added to water.
The inflorescences are sprayed or, for better contact with the hormone, dipped in a container with a solution. The procedure is carried out twice during flowering (in the middle and at the end) and a week after the end. The normalization of the load is carried out after the formation of bunches.
In the first year of using the hormone, the dosage is selected empirically, spraying grape inflorescences with solutions of different concentrations. At the end of fruiting, the optimal rate of alcohol solution per 1 liter of water is determined.
Contraindications for use
The phytohormonal agent is not recommended for use for bisexual varieties, since it does not significantly affect the yield increase. Overconcentration for seedless cultivars and unisex hybrids results in thickened brushes.
Too tight adhesion of the berries causes them to crack, and the development of gray rot.
Crop care after processing
After spraying with gibberellin, the plants require intensive care: watering, feeding, removing weeds. An accelerated metabolism requires an increased supply of nutrients.
The nuances of storing gibberellin
Dry gibberellin is stored according to the conditions specified by the manufacturer. An alcohol solution in a glass container retains its working properties for an unlimited period. A water-alcohol solution is suitable for use for no more than 3 days.
To increase the yield and presentation of table grape varieties (hybrid unisexual forms and raisins), different variants of gibberellins are used. The phytohormone "Gibberellin" contains gibberelic acid A3.
Phytostimulants are commercially available containing several varieties of gibberellins and additional components:
- Gibbersib. The active ingredient is a combination of gibberellins A3, A7.
- "The ovary is universal." The active ingredient is sodium gibberellic acids of increased concentration.
- "Bud". The active ingredient is sodium gibberellins of high concentration in combination with humates and trace elements.
Fruit-forming preparations "Universal ovary" and "Bud" are used not only for vineyards, but also for growing vegetables, flowers, fruit trees.