Efficient cultivation techniques of seedless watermelon

The growth of seedless watermelon is roughly the same as that of ordinary watermelon, so its cultivation technique is similar to that of ordinary watermelon, but seedless watermelon also has many unique characteristics, such as low seed germination rate, low seedling rate, slow growth in the early stage, exuberant growth in the middle and later stage, pollen abortion, low natural fruit setting rate and so on. Therefore, the corresponding technical measures should be taken in cultivation and management in order to obtain high yield and high efficiency.

Melon field preparation

Although seedless watermelon is not strict on soil, it is still necessary to create a better suitable environmental condition for its high yield in terms of high yield and high quality. Because seedless watermelon has the characteristics of continuous cropping, waterlogging, drought and developed root system, the fields with high dryness, sufficient sunshine, deep soil layer, good permeability and convenient drainage and irrigation should be selected to ensure the normal growth and development of seedless watermelon. After thawing in early spring, rake fine and level the melon field, dig the melon ditch according to the predetermined row spacing, the ditch is 30cm of depth and width. Irrigate enough moisture at the bottom, apply 4,000 kilograms of high-quality rotten farm manure per mu, 50 kilograms of nitrogen, phosphorus and potassium ternary compound fertilizer, or 50 kilograms of special fertilizer for watermelons, spray phoxim disinfection, and then cover the border with film. This work should be carried out 7 days before planting.

Sowing and raising seedlings

The temperature requirement of seed germination and seedling emergence of seedless watermelon is higher than that of seeded watermelon, the growth before the two-leaf stage is slow, and the cold resistance of seedlings is weak, so it is generally produced by seedling transplanting and direct seeding cultivation in some places.

1. Nursery bed preparation: establish a seedbed in a greenhouse or a small arch shed. The seedbed is generally 1.2 meters wide, 15-20 centimeters deep and 8-12 meters long. On the north side of the seedling bed in the small arch shed, the wind barrier is made of sorghum or corn straw. Nutritious soil is generally prepared according to the proportion of four parts of original soil and one part of rotten barnyard manure, adding appropriate amount of methyl thiophanate and trichlorfon to disinfect, fully mixed, sifted, loaded into a nutrition bowl, covered with plastic film to increase temperature.

2, soaking seeds to promote germination: first, pour boiling water and cold water into a clean basin in a ratio of two to one, set the temperature to about 55-60 ℃, put the seeds in and stir quickly until the temperature drops below 40 ℃, stop stirring, and soak the seeds for 1-1.5 hours. Remove the sticky material from the surface of the seed by scrubbing it repeatedly. Because the seed embryo of seedless watermelon is incomplete, the seed coat is thick, and it is difficult to germinate, so the shell-breaking treatment should be taken before germination to improve the germination rate. Generally use teeth to gently open the suture line of the seed navel 1/3, you can also use nail Clippers to open the seed navel, be careful not to damage the seed embryo. Do not open the hilum too much, so as not to peel off the seed coat in the process of budding. The chewed seeds are rolled with a dry wet cloth and placed in a 33-35 degree incubator to germinate. After 20 Murray for 24 hours, the budding seeds are picked out, and the remaining seeds continue to germinate. In rural areas, hot kangs, electric blankets and stoves are generally used to promote germination, but the temperature and humidity must be controlled to ensure the smooth germination of seeds. Special attention should be paid to the process of budding:

① maintain appropriate humidity, do not add water or leaching at will, prevent excessive moisture in germination bed and seeds, cause rotten seeds or rotten buds, and do not make seedbed humidity too low to prevent seeds from drying.

② maintains a relatively constant temperature to prevent drastic temperature changes, drastic cooling or excessive temperature will lead to the loss of germination ability of germinating seeds.

③ keep the seeds ventilated and do not germinate in tightly sealed, airtight containers or plastic films.

3. Sowing: it is suitable for North China to sow seeds at the end of March and the beginning of April, and water the soil moisture thoroughly the day before sowing. Sowing should be carried out under sunny and windless conditions. When sowing, use a small wooden stick to make a small hole in the center of each nutrition bowl, then place the seeds flat in the seedling soil, make the buds down close to the hole wall, and sow one seed at each nutrition bowl point. Cover it with sifted fine soil in time, and the thickness should not exceed 1 cm. Sowing starts from one side of the seedbed and covers the film while sowing.

4. Seedbed management: the seedling stage of seedless watermelon is generally about 30 days. According to the law of germination and seedling growth, seedbed management can be divided into three stages: the first stage, from sowing to unearthed cotyledons, the focus of management is to raise the temperature and "take off the cap". The temperature is kept at 30-35 ℃ during the day, the grass curtain is properly covered to prevent cold at night, and the ground temperature is kept at 18-20 ℃ at night. Unearthed seedless watermelon with shell is a common phenomenon in seedling rearing. When the seed coat is soft, gently remove the seed coat with both hands or tweezers every morning, and be careful not to damage cotyledons and young stems. In the second stage, from the micro-expansion of cotyledons to the exposure of the first true leaf, the focus of management is to control moisture and lower temperature to prevent high temperature from growing to form tall seedlings. During this period, the temperature should be controlled at about 25 ℃ during the day and 15-20 ℃ at night. If the temperature is too high, the film mouth should be opened for ventilation and cooling. The position of ventilation is generally on the leeward side, and ventilation is generally from 10 am to 4 pm. In the third stage, the seedlings break their hearts to 2-3 true leaves, and the management focuses on temperature and humidity. The seedling bed temperature was appropriately raised to 25-30 ℃, and the ventilation time was appropriately prolonged. The seedlings were exposed 3-5 days before transplanting to enhance the stress resistance of seedlings. Humidity is strictly controlled in the seedling stage, as long as there is sufficient water at the bottom of the seedling bed, do not water as far as possible, if there is a shortage of water, you can sprinkle the kettle in the sunny morning to maintain a certain degree of humidity. Water once in the afternoon before transplanting to prevent root damage when transplanting. In addition, timely attention should be paid to the removal of weeds and spraying to control stunting diseases and various pests.

5. Pollination varieties: the pollen of male flower of seedless watermelon has poor development and almost no vitality, which can not stimulate the ovary of female flower. Only by means of pollen stimulation of ordinary watermelon can it grow into seedless watermelon. Pollination varieties should be selected from the local main varieties of seeded watermelon, the skin color of fruit should be different from that of seedless watermelon, in order to identify, the ratio of seedless watermelon to seedless watermelon is generally 9-10: 1. In order to meet the flowering stage of pollinated varieties and seedless watermelons, pollinated varieties should be sowed late for 5 days.