Key Technical Points and Detailed Operation Methods for Apricot Tree Propagation
In recent years, as the market for major fruits such as apples and pears has gradually become saturated, the market potential for minor fruits is relatively large, especially with promising prospects for fresh-eating apricots and kernel apricots. Apricot trees are deeply favored by fruit growers for their strong adaptability, ease of cultivation, low investment and quick returns. Most rural areas use seedling propagation, whose offspring vary greatly and do not easily...
In recent years, as the market for major fruits such as apples and pears has gradually become saturated, the market potential for minor fruits is relatively large, especially with promising prospects for fresh-eating apricots and kernel apricots. Apricot trees are deeply favored by fruit growers for their strong adaptability, ease of cultivation, low investment and quick returns. Most rural areas use seedling propagation, whose offspring vary greatly and do not easily maintain the fine traits of the original variety. The author's experience in recent years in cultivating apricot grafted seedlings is presented here for the reference of the broad community of fruit growers and seedling producers.
I. Rootstock Propagation
For apricot seedling propagation, the rootstock can be either a common rootstock or a different-species rootstock. Common rootstocks include common apricot (Prunus armeniaca) and mountain apricot (Prunus sibirica); different-species rootstocks include mountain peach and mountain plum. However, mountain apricot is mainly used. Rootstock seeds must be fully mature and stored in a dry place to prevent mold. Sowing can be divided into autumn sowing or spring sowing.
1. Autumn sowing. This should be carried out before the soil freezes. First, apply sufficient organic fertilizer to the nursery land and prepare the soil finely. Then soak the seeds in 50°C warm water for one day and night, or sow the seeds directly in furrows without treating them. Per 667 sq m, the seeding rate for common rootstock is 50-70 kg, and for different-species rootstock 40-50 kg. When sowing, single-row or wide-narrow row drilling can be used. For single rows, the row spacing is generally about 40 cm; for wide-narrow row seedling culture, the wide row is 50 cm and the narrow row is 30 cm. After sowing, cover with about 8 cm of soil, and finally irrigate with sufficient winter water.
2. Spring sowing. Because the rootstock seed shell is hard and woody and not easy to crack, it must be treated before sowing. ① Sand storage. Before winter sets in, treat the seeds by sand storage. Choose a shady, high and dry place and dig a pit 60 cm deep and 1 m wide, with the length determined by the amount of seed. First spread a 15 cm thick layer of sand at the bottom of the pit, then mix 1 part seeds with 2 parts wet sand evenly and place them in the pit for sand storage. Cover the upper part of the pit with 20 cm of wet sand, then cover with soil mounded above ground level in the shape of a steamed bun, with a thickness of 10-20 cm. Mountain apricot seeds have thicker shells, and the sand storage period is generally more than 3 months. The earlier the sand storage, the more seeds naturally crack the following year. ② Seed soaking. For spring sowing, stored seeds can be soaked, placed in plastic bags, and directly exposed to sunlight, sprinkling water and stirring once every 2-3 days; after 15 days, sow once the seed pits have cracked. ③ Artificial cracking. If the amount of seed is small, the shells can be cracked artificially before spring and then soaked in warm water to promote germination before sowing. ④ Sowing. Take out the seeds treated by the above methods and sow from late March to early April. Before sowing, irrigate the nursery land once; after the water has penetrated, apply sufficient base fertilizer, prepare the soil and open furrows for drilling.
II. Seedling Grafting
1. Variety selection. Xinshiji, Hongfeng, Zaohong, Hongguang, Jintaiyang, Zhongmi No.1, Hongguanzhong, etc. For cleft grafting or wood-bearing bud grafting, the scions need to be cut the previous year and stored in sand, and taken and used as needed during spring grafting; for bud grafting, they can be cut directly from the mother tree.
2. Grafting methods. ① Summer bud grafting. In mid-to-late July, when the rootstock reaches the thickness of a chopstick, use the "T"-shaped budding method for grafting. Apricot buds are relatively soft, so insertion should be done slowly to prevent the bud from wrinkling and affecting survival. Also note that budding should be carried out on sunny days, as wounds are prone to gummosis in cloudy and rainy weather, reducing the survival rate. ② Spring grafting. Spring grafting can be carried out the following year when the sap flows, generally using methods such as cleft grafting, bark grafting, wood-bearing bud grafting and single-bud approach grafting. According to several years of trials, the cleft grafting method, due to its large wound, does not have as high a survival rate as the other grafting methods. After grafting, wrapping tightly with plastic film gives a higher survival rate than wrapping with plastic strips.
III. Management of Grafted Seedlings
For bud-grafted seedlings, promptly cut back the rootstock the following spring after the sap flows. On the basis of strengthening fertilizer and water management and weeding, frequently remove buds and suckers so that root nutrients are concentrated in supplying the new shoots sent out by the scion or grafted bud. When the seedling grows to 30 cm, promptly set up supports, and remove the wrapping plastic film according to growth conditions, to prevent wind breakage or girdling of the seedling.