Meixiang seedless (Chinese red rose) grape
Before the 1950s, although there were also large-scale viticultures in the world, most of the fruits produced were core, which was not particularly convenient to eat and affected the taste. Since American scientists first elaborated on the role of gibberellin in the formation of seedless fruits and enlarged fruit grains in grapes in 1959, a wave of grape seedless treatment research has been set off all over the world, such as the establishment of rose dew seedless and early maturing cultivation technology in Japan in 1958-1959; the seedless treatment of Chinese scientist Luo Guoguang on rose grapes in 1959-1962; and the streptomycin seedless treatment test on bud roses in Japan in 1971. However, from the current grape denuclearization treatment technology, or Japan's technology is quite mature, the research is more in-depth, China is in the process of leapfrogging.
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The seedless treatment of grapes in China began in the research of Professor Luo Guoguang from 1959 to 1962, but because of its serious falling flowers and fruits, the phenomenon of large and small fruits was prominent, and the yield loss was outstanding, it could not be promoted in the end. After experiencing as long as the 1980s, this technology gradually became effective in China, such as in 1980, Teacher Wei Zhendong spent 5-10 days before spraying 15ppm to promote life to make the grapes seedless rate reach more than 90%, and then in 1985, two teachers in Shanghai soaked the flower spikes with 25ppm gibberellin at the end of the pioneer grape bloom, and once in 10 days, the seedless rate reached 90.3%-94.2%. After a period of time, most experts and scholars found that the application of gibberellin alone often because of its huge side effects, such as panicle shaft embrittlement, distortion, etc., so the research direction after that focused on the treatment of mixed agents, but also found some better collocation methods, such as gibberellin and streptomycin; gibberellin, streptomycin and CPPU (chloropyramide) and so on.
First, the theoretical basis of "denuclearization" treatment
1. Stimulation of endogenous hormones such as gibberellin, auxin and cytokinin in the ovary wall is the key to achieving fruit setting.
The fruit eaten by the grapes is developed from the ovary wall of the female flower; the seeds (grape seeds) are formed after successful pollination of grapes, and under the stimulation of endogenous hormones such as gibberellin, cytokinin and auxin synthesized during the seed formation process, the ovary wall cells divide the cells, the number of cells increases rapidly, and finally the development is fruitful.
If pollination fails, seeds cannot be formed, endogenous hormone stimulation is lacking, cells in the ovary wall cannot divide normally, ovary wall development is hindered or even stopped, and the young fruits formed are stunted or even shed.
Under the premise of adequate nutrient supply, whether the supply of endogenous hormones can be obtained to stimulate the division of ovary wall cells is the key to the development of the ovary wall, that is, the key to achieving fruit setting.
2. The essence of "seedless" technology is to use plant growth regulators to achieve fruit preservation and expansion
In plant growth regulators, there are multiple components with functions similar to cytokinin and auxin. Treating buds with these ingredients not only stimulates ovary wall cell division and achieves fruit setting. And by adjusting the use concentration, the quality of cell division can be improved, and the number of cells in the fruit can be further increased; or more nutrients can be induced to be transported to the fruit by the agent, which promotes better cell development to increase the cell volume.
In summary, the use of some plant growth regulators to stimulate the division of ovary wall cells can not only achieve fruit set, but also further expand the fruit, increase the size and weight of the fruit.
In order to ensure the quality of fruit set, in the production is generally before the emergence of a large number of physiological fruit drops after the emergence of grapes, the use of plant growth regulators, this time is mostly concentrated in 2-3 days after full flowering. The use of plant growth regulators at this time generally leads to the failure of grape seeds, that is, there are no seeds in the fruit (grape seeds). Therefore, in production, plant growth regulators will be used to promote the fading of seeded grape fruit into "seedless grapes", and the technology of fruit preservation and expansion at the same time will be carried out, called "seedless technology".
Second, "denuclearized" treatment of commonly used agents
At present, the agents used for "denuclearization" treatment mainly include gibberellomic acid, cytokinin, and auxin.
1. Gibberellosis
The effects of gibberellomic acid mainly include promoting inflorescence separation, fruit preservation, expansion, and pitting;
Several major endogenous hormones in the plant are in a state of dynamic equilibrium, and the fluctuation of the content of one type of hormone will inevitably cause changes in the content of other types of hormones.
The artificial use of gibberellose impregnated inflorescences directly increases the content of gibberellomic acid in the inflorescence, thereby stimulating the synthesis of cytokinin and auxin, resulting in an increase in cytokinin and auxin content. Therefore, the use of gibberellomic acid alone can also achieve fruit preservation.
In the process of nutrient distribution and infusion, gibberellose plays an important guiding role, which is basically a large supply of nutrients to plant tissues and organs with high gibberellose content. Inflorescences and young fruits are impregnated with gibberellose, resulting in increased gibberelloc acid levels and better access to nutrient supplies.
Gibberellose is the most commonly used ingredient that causes seed failure. For most varieties, the use of gibberellose within three days of flowering is basically seed-free (except for sun roses).
2. Cytokinin-like substances
Commonly used cytokinin substances mainly include chloropyrurea, thiabenilone, and 6-benzylaminopurine (6-BA). This kind of substance directly stimulates cell division and is the ingredient with the best fruit preservation effect. If the above ingredients are used during the peak period of ovary wall cell division, the quality of cell division can be further improved, the number of cells can be increased, and the effect on increasing the volume of fruit is the most significant.
These substances are key ingredients in grape fruit preservation and fruit expansion, and are significantly superior to gibberellosis alone. However, the increase in the number of fruit cells and the expansion of cell volume are based on nutrient supply, in production, the use of the above ingredients is generally added gibberellomic acid to induce nutrient supply to the fruit, better to achieve fruit setting and expansion.
Commonly used cytokinin substances, there are large differences in activity between different components: thiabenilone has the highest activity, followed by chloropyramide, and 6-benzylaminopurine is the weakest.
2.1 Thiophenone:
Thiphenylpron has the highest activity, so at the same concentration, thiabendron and extrusion fruit are the most active. However, after the use of thiobenzoluene, it will generally increase the difficulty of coloring the fruit, so thiabendron is mostly used for the treatment of yellow-green varieties (such as drunken golden incense, sunshine rose, seedless white chicken heart), and is not recommended for the treatment of colored varieties.
The use of thiobenzolyl treatment of the fruit is generally larger, so the risk of fruit splitting is bound to increase, for varieties of easy to crack fruit in production, it is not recommended to use thiobenzolonge treatment.
The larger the fruit, the later it is bound to ripen, so grapes treated with thiphenylphenone are bound to ripen lower than fruits treated with other agents under the same conditions. As picked at the same time, the quality of the grapes treated with thiobenzolyl is correspondingly poor due to insufficient ripeness.
Due to the high activity of thiphenylphenone, the stimulation of cell division is fierce, and if the concentration is used at a higher concentration, it may lead to slight malformation of the young fruit due to abnormal cell division. After the fruit ripens, there are raised ridges or sunken grooves on the surface of the fruit, which are usually a sign of treatment with higher concentrations of thiobenzolongol. Treatment with high concentrations of chloropyramide can also lead to deformed fruit appearance, but is rare in first-line production.
(The managed post will fill up and become oval, like blowing a balloon)
2.2 Chloropyrurea:
Chloropyrurea ingredient is moderately active, although the effect of the expansion fruit is not as good as that of thiabenron, but the adverse effect on fruit coloring after use is lower than that of thiabenron, so chloropyramide is mostly used in the treatment of colored grape varieties. However, the excessive amount of chloropyrurea will also adversely affect the coloring of the fruit.
Chloropyrurea-treated fruit is generally rounded; for example, the use of chloropyrurea in a large concentration will lead to an increase in the astringency of the peel in most varieties. The above phenomenon is a sign of treatment with chloropyrurea.
2.3 6-Benzylaminopurine:
6-Benzylaminopurine is a milder cytokinin substance, among the commonly used ingredients, 6-benzylaminopurine activity is low, and the fruit volume obtained by using this ingredient at the same concentration is smaller than that of other components.
6-Benzylaminopurine has the least side effect on fruit development, and under normal use, this ingredient will not only not cause the peel to be astringent or hinder coloring, but also accelerate reproductive development, that is, accelerate the growth and development of the fruit, accelerate the ripening and coloring of the fruit.
The fruit treated with 6-benzylaminopurine is generally oval, and the elongated fruit grain is the unique function of the ingredient, and the fruit treated with this ingredient is generally colored early and well in the later stage compared with other components. The above phenomenon is the main feature of treatment with 6-benzylaminopurine.
Although the fruit preservation of 6-benzylaminopurine, especially the puffed fruit, is not as effective as other ingredients, it is the preferred treatment ingredient for the production of high-quality fruits, regardless of fruit size. Alternatively, the ingredient can be used as an adjunct to promote fruit expansion, and when used with chloropyrurea or thiobenzoluone, it can improve fruit quality to a certain extent.
Crimson seedless grapes
3. Auxin ingredients
Auxin is another key hormone that promotes ovary wall cell division and achieves fruit setting. As the name suggests, auxin plays an important role in cell growth.
In the "denuclearization" treatment, there are three main types of means to artificially increase the content of auxin:
1) By using gibberelloyric acid, stimulate the increase of auxin content in plant tissues;
2) Direct supplementation with natural growth hormone ingredients - indoleacetic acid. For example, the essence of seaweed extracted from the cold polar waters or the poor growth environment of the deep sea, and the natural active substances extracted from plant seeds, which contain a higher content of auxin (such as Bihu, Mindrida Biyi). Since they are all natural substances, one is conducive to absorption, and the other is that fruit development is not sensitive to dose, and even higher doses will not lead to more obvious adverse effects.
3) Use synthetic ingredients with auxin function, such as naphthaleneacetic acid, 2,4-D, etc. Under the appropriate dose of the above substances, it has the function of flower preservation and fruit preservation, but the concentration is slightly higher, which is manifested as the reaction - flower thinning and fruit thinning. Due to the synthetic substance, the activity of the agent is significantly affected by temperature and tree potential, and it is difficult for the general grower to accurately grasp the effective dose, so it is not recommended.
In actual production, if the amount of gibberelloc acid is simply increased to increase the auxin concentration, it generally leads to excessive inflorescence separation, thickening of fruit stems, excessive lignification of fruit stems, and aggravates the risk of graining in the later stage.
Experiments have proved that in the fruit preservation treatment, the addition of natural auxin ingredients to the agent not only has a better effect on fruit preservation and expansion, but also has a certain effect of softening the stem.
Seedless grape varieties recommended:
Fragrant seedless grapes (ripened in mid-September): natural seedless, rich in flavor, hard and crisp in flesh, large, non-splitting fruit threshing Resistant to storage and transportation
Crimson seedless grapes: hard and crispy flesh Sweet and juicy, excellent quality, super rich yield, extremely resistant to storage and transportation
Sleeping Beauty Grapes: Originated from the United States Seedless Grapes are the best natural seedless fruit grains are extremely long shelf life
Madonna Ruby Grape: Noble of the table grape variety, the flesh is hard and crisp, and the palatability is excellent
Tiangong Moyu grape (ripe in June): extra early ripening, seedless new product, crisp flesh, high sugar, good disease resistance