Mosha Town, Xinping County, Yunnan Province, has been planted for nearly five years. At present, there are 4793 mu of litchi orchards in the town (1 mu =115 hectares), including 2080 mu of newly planted litchi in Shuidong, old varieties grafted and improved litchi in Shuidong 1.540 mu, local varieties and others. In the extension and planting of newly planted litchi, Xinping County Precision Work Station and Mosha Town Agricultural Technology Center undertook the propagation, grafting and extension and planting of litchi seedlings, and accumulated some techniques and experiences in seedling propagation. Based on the production practice, the author introduces the technical methods of litchi seedling raising as follows for reference.

1, seedling grafting propagation

(1) Selection of nursery

The selection criteria are rectangular, with abundant sunshine, open terrain, sufficient water, convenient irrigation and drainage, complete water conservancy ditches and roads, which are suitable for the operation needs of nursery construction.

(2) Fertilizing the nursery land

The cohesiveness of seedbed soil should be suitable for rootstock growth and soil consolidation. For the fertile soil with weak viscosity, it is not suitable to use mud balls to raise seedlings, and it is necessary to use seedbeds with different soil qualities. If the seedbed is paddy field, it is necessary to control water, plough, dry in the sun and ripen deeply, which is beneficial to improve the ground temperature and soil oxygen content, kill soil germs and eggs and loosen the soil. On the basis of controlling the turning over of the field, hauling red clay from other places to mix and enhance the adhesion is beneficial to raising seedlings with mud in the future, which is the key measure to ensure the survival of bare seedlings. It is suggested that according to the fertility level, 500 ~ 600 kg of decomposed sheep manure, 50 ~ 100 kg of calcium superphosphate, 50 ~ 100 kg of compound fertilizer and 50 kg of lime should be applied per mu, and they should be fully and evenly mixed with soil.

(3) Soil moisture of seedbed

After the nursery soil is fertilized for 2 months, adjust the soil moisture of the seedbed. The specific operation is as follows:

(1) Soil surface modification. The soil surface is 2m wide, and its length depends on the site topography and soil shape. The ditch is 30 cm wide and 30 cm deep, and the drainage ditch is 50 cm deep. After the sowing water is separated, level the broken soil and wait for sowing.

② Set up fences. In order to prevent pigs, cattle and other livestock from trampling into the nursery, cement bricks can be placed around the nursery, tied tightly with iron wires, or made into fences with bamboo poles.

③ Build a shade shed. The shed has a span of 6m, a length of 15 ~ 20m, a shoulder height of 1 ~ 1.5m, a ridge height of 1.8 ~ 2m, and a shed bottom section diameter of 6m. According to the width (span) direction of the shed, an upright post is set every 2m, with a thickness of 6-8cm, an arch at the top and a buried depth of 50cm. Bamboo poles are fixed at the top of the upright post to form an arch, and cross bars at both ends are buried underground and compacted. Arch distance 1m, connected into a whole by longitudinal tie rods; The arch frame is covered with a sunshade net, and one end of the tensioned net is buried in the surrounding soil, and the sunshade net is pressed between the arch frames by pressing wires or No.8 aluminum wires and bamboo poles.

(4) rootstock culture

According to the experience, the old variety litchi has good affinity with Shuidong, Xiaohei Sanyuehong, Feizixiao and other varieties, and the local old variety litchi is selected as the grafting stock.

(1) seed collection and germination. After the fruits are ripe in April-May, the seeds of the old variety litchi will be collected intensively, and it takes about130,000 seeds to cultivate 100 seedlings. Litchi seeds should not be placed for a long time, but should be collected in batches to accelerate germination and sowing. Method of accelerating germination: Choose the flat land of 1, pile wet sand with a thickness of 3 ~ 5cm on it, spread the cleaned seeds on the sand surface without overlapping the seeds, then cover the seeds with straw with a thickness of 5cm, and often spray them with water to keep them wet, and take them out for sowing after the radicle of the seeds is exposed for 4 ~ 5 days.

② Seeding and seedling raising. The plant spacing is18cm×12cm. Carry out single-core sowing. When sowing, first open the sowing ditch according to the row spacing, and the depth of the ditch is about 3cm. The seeds are laid flat in the ditch according to the original plant spacing, and covered with soil after watering. The suitable thickness of covering soil is 2cm, too shallow seeds are easy to dry and die, and too deep seedlings are not easy to be unearthed.

(5) rootstock grafting

① scion selection. The grafted varieties are Shuidong, Xiaohei Sanyuehong and Feizixiao, and other varieties are properly matched. Pruning management should be done well in the early stage of picking, and 3-5-year-old fruiting mother trees should be selected as the cutting tree source, and 1-2-year-old branches with full growth, full bud eyes and mature leaves in the middle and upper parts of the crown should be selected. If conditions permit, you should prune and get married; If it doesn't need to be placed for a short time, it should be wrapped with fresh litchi leaves, then wrapped with a layer of wet towel, sealed with plastic bags and placed in a cool place.

② Grafting time. According to the experience, it is better to graft litchi from March to April every year, and replant it in September-65438+1October of that year.

③ Grafting method. Seedling grafting in nursery adopts the methods of branch grafting and cutting grafting. First, cut the roots. Cut the top of the rootstock 3 ~ 4cm away from the ground, select a plane, cross the 1 knife upward to form a 45 inclined plane, and cut the 1 knife vertically downward along the cambium or slightly xylem in the flat part below the inclined plane, with a length of 3 ~ 4cm. Step 2: Cut the scion, with the branches of the scion going straight down, and the lower ends of the branches are cut into inclined planes with a 45-degree angle. Turn the branches so that the straight faces face upwards, cut the scion down to the cambium or slightly xylem, and cut out smooth long sections slightly longer than the rootstock incision, leaving 2-4 buds. Finally, joint and seal. Insert the cut scion into the incision of the rootstock, make the cambium between the rootstock and the ear align with each other, tie it tightly with film tape, and seal it.

(6) The seedlings leave the nursery.

① Seedling standard. First, the compatibility between rootstock and scion is good, and the joint develops evenly from top to bottom, and there are no undesirable phenomena such as base expansion or yellowing of trunk and leaves caused by late unbinding. Second, the grafting site is 30 ~ 35cm, not too high, the trunk is thick and straight, the seedling is 50 ~ 60cm high, with 3 ~ 4 branches, healthy growth, neat leaves and dark green. Third, the branches are thick and the roots are developed.

(2) Seedlings leave the nursery. Firstly, a cylindrical seedling lifter is made, centering on the trunk of the seedling, the seedling lifter is inserted into the soil from both sides of the seedling, and the seedling lifter is struck with a sledgehammer until the seedling lifter is completely inserted into the soil, then the iron handle of the seedling lifter is grasped, the seedling lifter is pulled up together with the soil and the seedling, the excessively long main root is cut off, and the seedling lifter is opened to obtain litchi seedlings with cylindrical mud blocks; Then wrap the dug seedlings in film, and tie the film tightly with fiber tape, so that they can be supplied from the nursery.

③ Transportation and supply. When the first grafted seedling is slightly aged and mature, it can be planted out of the nursery. In the process of transportation, it should be placed neatly, and it can be placed in two layers. Seedlings must be transplanted and planted within 3 days of the same day, and the perennial planting time is from June to 10.

(7) Management and protection of nursery land

In addition to guarding the property and saplings of the base, the management and protection personnel also shoulder the daily management and agricultural operation of the nursery.

(8) Seedbed management

① Post-sowing management. That is, the management from sowing to grafting. The first is water management. After sowing, water should be sprayed frequently on sunny days to keep the soil moist, which is conducive to the emergence of seeds. Second, fertilizer management: when the first true leaf of seedlings turns green, dilute manure water is applied, then ternary compound fertilizer and potassium sulfate are lightly applied, and the surface is covered with plastic film at low temperature in winter to increase the temperature of seedbed; Finally, the management of pests and diseases, do a good job in the prevention and control of underground pests, and pull out dead seedlings in time.

② Management of grafted seedlings. That is, the management from grafting to leaving the nursery. First of all, the survival of grafted seedlings should be ensured, and those that have not survived within 20 days after grafting should be replanted in time, followed by unbinding After checking the survival, it is necessary to cut the film at the bud eye in time to let the bud grow, and cut off the anvil top in time after grafting to accelerate the germination and growth of the grafted bud. Third, erase the roots and buds. After grafting, rootstock buds often germinate and should be erased in time to ensure the growth of buds and branches on the scion. Finally, tree shaping and strengthening fertilizer and water management. When the seedling height is 40 ~ 50 cm, it is necessary to trim and cultivate strong main branches, and select 3 ~ 4 evenly distributed strong branches to cultivate main branches. At the same time, it is necessary to strengthen the management of fertilizer and water, ensure "two fertilizers at both ends", and give priority to watering without irrigation. Fertilizers such as urea, potassium sulfate and compound fertilizer can be applied appropriately, and the amount of fertilization depends on soil fertility and seedling conditions.

③ Management of nursery seedlings. The first is the management of seedlings leaving the nursery. Before leaving the nursery, topping should be done 1 month to make the branches mature and strong, and more lateral branches should be added. When leaving the nursery, the seedlings should be raised one by one. If the seedlings are too small to leave the nursery, they should be submitted and management should be strengthened. Secondly, seedling sales and seedling prices should be set reasonably. If the construction of nursery land is a government action, it should be based on the principle of parity or small profit supply.

2. High pressure seedling raising

Litchi high-pressure strip seedlings, also known as high-pressure seedlings, have simple technology, easy operation, short seedling raising time and early fruit after planting. It is suitable for use when the mother seed source can meet the requirements. But this method has low reproduction coefficient. In the case of few excellent mother trees, it can not meet the needs of seedlings. After planting, the management is slightly poor, the survival rate is low, and the slow seedling stage is long. The breeding season is generally from April to June. At this time, breeding can grow roots 2 ~ 3 times in the autumn of that year, and then heel planting can be carried out in the same year or the same year.

Branch selection of (1) high-pressure seedlings

First, the selected varieties should be determined. Secondly, robust fruit trees with a diameter of 1.5 ~ 2 cm and robust branches that can see the sun without pests should be selected. In short, the branches used for high-pressure seedling raising should be selected from the fruiting mother trees with strong, high and stable yield, high quality and excellent characteristics of this variety.

(2) girdling, stripping and bandaging

Cut the selected branches twice with a ring knife at the selected position, reaching the xylem with a distance of about 3cm, then peel off the cortex between the two knives, smear the incision with 5‰ indolebutyric acid, wrap the root-promoting matrix (such as the mixture of lichen and fine mud containing humus), and tie it into a shuttle shape with plastic film. Generally, the newly grown white tender roots can be seen outside the dressing after 30-40 days, and the roots will grow 2-3 times after 50-60 days. At this time, the high-pressure seedlings can be cut off from the mother and become new plants for follow-up or colonization.