There are two basic types of seedless technology: one is to dip the fruit spike with 100 mg/l gibberellose two weeks before flowering to induce it to produce seedless fruit, and then repeat the treatment again about 10 days after flowering to expand the berries. This model was established and quickly promoted on rose dew grapes, and later successfully applied on bud A; The other is the pioneer model of tetraploid grapes, which was first treated at the end of the bloom, with gibberellose 12.5 to 25 mg/L, and then repeated after 10 to 15 days.
The grape denuclearization technology consists of three elements, namely, variety selection, pharmaceutical treatment and supporting cultivation technology, which constitute a complete set of denuclearization technology, which is indispensable.
Variety selection is a prerequisite for successful denuclearization. Varieties suitable for denuclearized cultivation should have the following conditions at the same time: (1) the rate of non-seeding should be higher than 90%, and most varieties can meet this condition;
(2) Varieties with mild side effects after treatment with regulators such as gibberellose, which are easy to cause panicle shaft distortion, wood pegs, thickening and hardening of fruit stems, and berry shedding, are not suitable for non-nuclear treatment;
(3) The size of the fruit grain after seedlessing should be similar to that of the same variety of fruit grain;
(4) The denuclearization effect is stable, and it is less affected by the environment, year, cultivation conditions, etc. The varieties that can meet the above conditions are mainly rose dew, pioneer, bud A, Jingya, Jufeng and Drunken Golden Fragrance. Among them, the stability of Jufeng is poor, and the operation technology is difficult.
The purpose of the first treatment is to induce the production of seedless fruits, which is the core of the technology, mainly composed of the main agent, auxiliary agent, concentration and treatment time. The second treatment of the denuclearizing agent is to enlarge the fruit grains to their normal size.
The effects of grape denuclearization on berry development are manifold. Pioneer, Giant Peak, Rose Fragrance and other varieties have significantly improved the fruit set rate during flowering treatment. Not only do they get seedless grapes that are popular in the market, but also the hard core period is shortened due to the disappearance of seeds, and the fruit can ripen 10 to 21 days earlier, so that it can be marketed early. The flesh of the seedless berries becomes slightly crisper and the flavor remains unchanged, and when fully ripe, the flavor exceeds that of the core grapes picked at the same time.
The requirements for the tree body in grape seedless cultivation are that the tree is strong, the branches grow neatly, the inflorescence size is consistent, and it is easy to operate. The Giant Peak grapes are more demanding because they are more difficult to pitted than rose dew grapes. In order to achieve the requirements of the seedless grapes of the Giant Peak System, it is necessary to adopt techniques such as short-shoot pruning, yield control, and fruit spike shaping that match the denuclearization. If the denuclearization technology is not matched, it is not appropriate to engage in denuclearization cultivation. The tree shape of the grape can be divided into two categories, namely long-cap pruning tree shape and short-cap pruning tree shape.
The short-stemmed tree-shaped branches grow neatly, grow strongly, are easy to operate, and meet the requirements of seedless cultivation. The representative short-shoot pruning tree shape is the dragon thousand tree shape, such as the single dragon thousand shape and the horizontal shape of the arms in the north of China, and the japanese have a zigzag shape and H shape. Okayama, Japan, is the main production area for the seedless cultivation of pioneer grapes, and the trees are more H-shaped or X-shaped. At present, more than 50% of the varieties of giant peaks and giant peaks in China are pruned with long shoots
Free fan-shaped whole branches are mainly, which is not suitable for seedless cultivation of grapes. Changing the tree shape and pruning method is an important condition for the success of Jufeng's denuclearization cultivation. Panicle shaping and grain thinning are also key techniques for the seedless cultivation of Grapes in the Giant Peaks. It is usually required to trim the panicle before the initial flowering, cut off the sub-panicle and its sub-panicles, and leave only the spike tip with a length of 3 to 4 cm (pioneer grape) or 5 cm (Anyun queen grape) (note that the spike tip is not allowed during seedless cultivation), because the spike tip part of the flowering is neat and neat, which is convenient for medicinal treatment, and the shape of the future panicle is long spherical and beautiful.
As for the number of fruit grains in the fruit spike, due to the increase in fruit set of the seedless treatment, if there is no thinning, the number of fruit grains is too much, and the removal of too many fruit grains is an important part of the success of seedless cultivation. Generally, when the fruit grains are large, the endophytes, crosses and a few seeded fruit grains are removed, and 30 to 40 grains are left per panicle. In recent years, Japan is exploring a seedless cultivation method that saves labor, and it is reported that the use of a seedless cultivation method that replaces the main panicle can improve the speed of fruit spike shaping without the same effect.
Grape denuclearization production has attracted the attention of grape producers across China, but denuclearization is a variety of plant growth regulators and supporting cultivation measures of the comprehensive application of technology, the requirements are higher, in addition, the variety of reactions are quite different, some varieties of side effects are very serious, to effectively master the feasible denuclearization technology can be widely promoted and applied.