(1) Reproduction methods

Strawberry reproduction has four methods: stolon propagation, new stem division propagation, micropropagation and seed propagation. The first three are asexual propagation, and the offspring can Maintaining a high degree of genetic consistency with the parent generation, seed reproduction is sexual reproduction, and the offspring have great variation, and are mainly used for breeding new varieties.

1. Stolon propagation

The propagation method of forming daughter plants through stolons is a conventional propagation method commonly used in strawberry production. It has the advantages of simple method and convenient management. Each ordinary strawberry seedling can produce several stolons, forming dozens of seedlings in each growing season, and tens of thousands of production seedlings can be reproduced per 667m per year.

2. Propagation of new stems and divisions

Strawberry plants can sprout several new stem branches when they grow into autumn. When each new stem branch has 4 to 5 leaves and many new roots, it can be divided. transplant. The method is to dig out the whole strawberry plant, cut off the aging rhizomes and separate the new stems. Each new stem seedling should be cut to leave a good root system (the lower part has 4 to 5 new roots with a length of more than 4cm), and then Plant as soon as possible. For strawberry varieties that are not prone to stolons, new stem division propagation can be used when seedlings are insufficient.

3. Micropropagation

Micropropagation is also called in vitro propagation, which is propagation through tissue culture. Strawberry micropropagation is to inoculate strawberry micro-shoot apex meristems on a suitable medium to induce young shoots, which will germinate and proliferate through axillary buds in test tubes. After the test tube seedlings are acclimated, they are transplanted to the greenhouse and transplanted into viable test tubes. The seedlings can be used as mother plants for field propagation. The advantages of micropropagation are: ① It can effectively remove strawberry viruses and obtain virus-free original seedlings; ② The propagation cycle is short, fast, saves land, and is not affected by environmental conditions. It can be produced in a factory, using one stem tip to produce Thousands of detoxified original seedlings can be propagated within a year, and new varieties can be quickly promoted; ③ Test tube seedlings have strong field propagation capabilities; ④ Production seedlings propagated with detoxified original seedlings grow more vigorously than those propagated with ordinary seedlings , the output increases by 15%~30%.

(2) Field stolon propagation and seedling cultivation

The yield of strawberry is composed of factors such as the number of inflorescences, the number of flowers, the grade fruit rate and the size of the fruit. It is closely related to the nutritional status of the plant and the The development status of the roots is closely related, and the quality of the production seedlings determines the level of yield. Therefore, cultivating high-quality production seedlings is the basis for high yield and high quality.

In terms of production, after the berries are harvested, some growers divide the plots planned for breeding in the production garden into alternate rows to make room for them, and then loosen the soil and rake it flat to facilitate the growth of the remaining plants. The stolons take root and form seedlings. However, the quality of the seedlings propagated in this way is poor and the reproduction volume is small. In order to ensure the quality of seedlings, a specialized strawberry propagation nursery should be established. The specific methods are as follows:

1. Mother plant selection

Select pure and robust virus-free original seedlings, first-generation seedlings or second-generation seedlings as mother plants for breeding and producing seedlings.

2. Seedbed preparation

The nursery should be selected on a plot with flat terrain, loose soil, rich organic matter, convenient drainage and irrigation, and sufficient sunlight. It is best to choose an area where strawberries have not been planted to propagate seedlings. After the nursery is selected, apply 5000kg of decomposed organic fertilizer, 30kg of superphosphate or 25kg of diammonium phosphate every 667m. Combined with the application of base fertilizer, the land should be plowed deeply to level the ground and mature the soil. After plowing and raking, make a flat or high border with a width of 1.0~1.5m. The border of the border should be straight and the surface of the border should be flat to facilitate irrigation. The soil should be properly settled before planting to prevent the seedlings from becoming uneven or showing roots after watering.

3. Planting

Plant the mother plant in spring when the daily average temperature reaches above 10℃. If the border is 1m wide, plant the mother plants in a single row in the middle of the border with a spacing of 50-80cm; if the border is 1.5m wide, plant 2 rows per border with a spacing of 60-80cm. The reasonable depth for planting plants is that the root neck is flush with the ground, so that the depth is not buried and the roots are not exposed. Soil should be used when planting to ensure survival rate.

4. Seedling management

Water thoroughly after planting to ensure adequate water supply in the future. After survival, carry out multiple cultivating and weeding to keep the soil loose. After stolons begin to appear, you can no longer cultivate, but weeds should be removed in time. In order to promote early and frequent stolons, gibberellin (GA) can be sprayed once after the mother plant is established and the concentration is 50mg/L. When the plant begins to grow vigorously, apply compound fertilizer once, and apply it by digging trenches 15 to 20 cm on both sides of the plant.

After stolons appear, spray 0.5% urea once on the leaves.

After the stolons emerge, arrange them evenly around the mother plant to avoid mixing them together or uneven density. When the stolons grow to a certain length and seedlings appear, dig a small hole at the node of the seedlings and build up soil to press the stems to promote rooting of the seedlings.

Remove the flower buds immediately when you see them. The sooner the better, so as not to consume nutrients. Removing flower buds is a key measure in seedling cultivation and cannot be ignored. When the new leaves unfold, the old dry leaves should be removed in time. During the entire growth period, with the emergence of new leaves and stolons, the lower leaves continue to age. Old leaves should be removed in time to prevent the old leaves from consuming nutrients, facilitate ventilation and light transmission, and reduce the occurrence of diseases. When removing old leaves, weeding should be done manually in time.

In addition to the above management work, attention should also be paid to the prevention and control of aphids, anthracnose, powdery mildew and other pests and diseases during the seedling stage.

(3) Fake planting seedlings

Fake planting seedlings are to transplant the stolon seedlings to a fixed place for a period of cultivation before planting them in the production field. The appropriate time for fake planting seedlings is 50 days before planting. Fake planting is conducive to flower bud differentiation and the seedlings are uniform in size.

1． Nutrient bowl fake planting seedlings

Select stolon seedlings with two leaves and more than one center and plant them into a plastic nutrient bowl with a diameter of 12cm or 10cm. The substrate is fertile topsoil free from pests and diseases, with a certain proportion of organic materials added to keep the soil loose. In addition, 20kg/m of high-quality decomposed farmyard manure should be added to the substrate. Arrange the nutrient pots with planted seedlings on the shelf or seed bed, with a spacing of 15cm between plants. Water thoroughly after planting, shade must be provided in the first week, and spray water regularly to keep it moist. Spray water 2 to 3 times a day. After survival, spray water 1 to 2 times a day. 0.3% urea was sprayed on the leaves 15 days after planting, and then compound fertilizer was sprayed on the leaves every 10 days. Before the flower buds differentiate, stop using nitrogen fertilizer and only use phosphorus and potassium fertilizers, topdressing every 7 days. Remove raw stolons and dead and diseased leaves in a timely manner, and carry out comprehensive pest and disease control. Seedlings in vegetative pots on the seedbed in the later stage need to be removed by transferring pots to control vegetative growth and promote flower bud differentiation. The most suitable method for promotion cultivation is to use nutrient pots to raise seedlings. After the pot seedlings are planted with soil, the seedlings will not slow down, grow and develop quickly, and bear early fruit.

2． Seedbed fake planting seedlings

The seedbed is 1.2m wide, and 3000kg of decomposed organic fertilizer is applied every 667m. Choose stolon seedlings with three unfolded leaves for fake planting, and the spacing between rows is 15cm × 15cm.

Appropriate shade. Water thoroughly after planting, and spray water twice a day within 3 days, and then water dry to keep the soil moist. Spray 0.2% urea on the leaves once 10 days after planting, and spray phosphorus and potassium fertilizers every 10 days. Remove raw stolons and dead and diseased leaves in a timely manner, and carry out comprehensive pest and disease control. Root removal is carried out from late August to early September.

(4) Standards for strong seedlings

Having more than four unfolded leaves, a rhizome thickness of more than 1.2cm, a well-developed root system, a seedling weight of more than 30g, terminal flower bud differentiation completed, and no pests or diseases.