The cultivation process of the latest seedless watermelon

Seedless watermelon is planted with seeds, but this seed is not the seed of seedless watermelon, but the seed of triploid watermelon formed by natural diploid watermelon and tetraploid produced by mutation. The cultivation technology has the same place as ordinary watermelon, but also has different places. Let's take a look at the cultivation process of seedless watermelon together!

Breeding Principle of Seedless Watermelon

Seedless watermelon is obtained by artificially inducing polyploidy, such as treating the seeds or seedlings of diploid watermelon with colchicine (a plant alkali) to hinder the formation of spindle filaments and primary walls in the metaphase of cell division, so that the duplicated chromosome set cannot be divided into two poles and form secondary walls in the middle, resulting in the formation of cells with doubled chromosomes and obtaining tetraploid watermelon plants. then crossing with diploid watermelon plant (as male parent) to obtain triploid seed, the triploid plant can not form normal germ cell due to the disorder of homologous chromosome association during meiosis. The triploid fruit was stimulated by mature pollen of diploid watermelon, because the ovule could not develop into seed.

Seed Cultivation of Seedless Watermelon

1. Artificial induction: seedless watermelon adopts the method of artificial induction of polyploidy, soaking the seeds of diploid watermelon with 0.2~0.4% colchicine (C22H26O6N) liquid for 12~24 hours, or dropping 0.2~0.4% colchicine liquid on the growth point of shoot tip of seedling at 6~7 o 'clock every day for four consecutive days.

2. Careful management: Wash the treated seeds or seedlings with clean water, and place the plants under astigmatism during treatment and slow seedling period to avoid direct sunlight irradiation causing colchicine decomposition and damage. At the same time, avoid high temperature, because in high temperature, colchicine toxicity to plants enhanced, easy to cause dead seedlings, in the survival of good cultivation conditions and careful management.

3. Bagging pollination: tetraploid watermelon is used as female parent, and diploid pollen grains are used to produce triploid watermelon seeds. Small area seed production is carried out according to watermelon flowering habits in the afternoon on time, and artificial pollination is carried out in the morning of the next day. At the same time, markers are hung. When large area seed production is carried out, it is necessary to isolate the tetraploid female parent and diploid male parent plants according to a certain proportion.

Seed Treatment of Seedless Watermelon

1. Seed selection and soaking: seed selection is carried out according to the shape, color, size and fullness of seeds according to the characteristics of varieties, tetraploid and diploid watermelon seeds are selected, and abnormal seeds, hybrids and inferior seeds are eliminated. Then a few days before soaking, dry the seeds for 1 - 2 days. Then the triploid seeds are put into warm water at 55℃ for stirring, and then the water is naturally cooled and soaked for 6~8 hours.

2, artificial shell: seedless watermelon seed shell method can be divided into dry seed shell and wet seed shell, the current mostly wet seed shell. Dry seed has high efficiency of breaking shell, but it is easy to damage seed embryo, and soaking time and soaking temperature are difficult to control, which affects the improvement of germination rate. Wet seeds are easy to break shell, low efficiency, but the length of soaking time has little effect on germination rate, easy to master, germination rate is high and stable.

3, seed germination: after soaking and shell broken seeds placed in 33~35℃ constant temperature conditions for germination, need to maintain a certain humidity. After 24 hours, more than 90% of the germination ability can germinate, the bud length of 0.5 can be picked out to sow, the rest continue to germinate, 36 hours after the normal seeds basically germinate. Seeds that do not germinate after 48 hours have lost their viability and do not need to germinate again.

4. Grafting seedlings: The low survival rate and slow healing speed of seedless watermelon grafting seedlings are common problems in current production, which restrict the development of seedless watermelon production and cause greater economic losses to melon farmers. In order to improve the survival rate of seedless watermelon grafting seedlings and cultivate healthy grafted seedlings, we must carry out grafting seedlings according to the structural characteristics and growth characteristics of seedless watermelon.

Field Management of Seedless Watermelon

1. Soil preparation and cultivation: 3~5 square meters of high-quality farm manure, 20 ~ 30 kg of urea, 20~30 kg of diammonium and 20 kg of potassium sulfate shall be applied per mu. The soil preparation shall be fine and the row spacing shall be 1.7~2 meters. High ridge cultivation, high ridge width 60 cm, height 15 cm or so, covered with 80~90 cm wide plastic film. Select windless sunny day planting, planting 500~700 plants per mu, watering with planting. The implementation of three vine pruning, leaving the main vine the third female flower fruit best, avoid low node sitting melon.

2, fertilizer and water management: seedless watermelon seedling stage (before and after the tree) per mu topdressing urea 5 kg to promote seedling growth, flowering and fruiting period generally do not water, do not fertilize. When watermelon is as big as duck egg, it has basically stabilized. Applying one time of swelling fertilizer, urea 15~20 kg/mu, potassium sulfate 15 kg/mu, spraying 0.2% potassium dihydrogen phosphate on leaves at the later stage of growth can improve yield and quality.

3. Artificial pollination: seedless watermelon adopts artificial auxiliary pollination, with strong purpose, early and orderly fruit setting, and consistent fruit maturity. At about 8 o 'clock in the morning, pollinate the female flowers of seedless watermelon with the male flowers of the pollinated varieties that open on that day. The earlier the pollination time after flowering, the better, no later than 10 o' clock. A male flower can be pollinated with 3~4 female flowers. Pollinate evenly and gently to avoid damaging stigma.

4. Reasonable ripening: seedless watermelon can be ripened with ethephon when it needs to be listed in advance. When the size of the fruit is considerable but not yet mature, each kilogram of watermelon can be smeared with 200 mg of ethephon solution along the melon surface before and after evening. A small amount of neutral soap powder can be added to the solution to increase adhesion. It can be harvested and listed in two days, and can be supplied to the market 3~5 days earlier than natural ripening.