Method for improving yield and tree vigor balance of grafted Korean pine cones in semi-arid region

Abstract

The invention provides a method for improving yield and tree vigor balance of grafted Korean pine cones in a semi-arid region, and belongs to the technical field of forest cultivation. In the semi-arid region, 2-3 annual cones are uniformly reserved on bearing branches of Korean pine different-stock grafted young trees which are grafted for more than 4 years and are in the early stage of fruiting; selecting medium and large fruit type scion-picking seed trees; collecting medium and large fruit type scions, and storing at low temperature; selecting pinus sylvestris or pinus tabulaeformis branches as stocks for different-stock grafting; or selecting a partial female Korean pine grafting branch as a stock to perform different-stock grafting or same-stock grafting, and starting stock cutting and unbinding, shaping and pruning and timely fruit thinning from the next year after grafting survival according to a cultivated target tree shape. Through selection under the extreme drought condition, the scion stress resistance is enhanced, and the preservation rate of the Korean pine different-stock fruit forest in the semi-arid region is improved; the pollen amount of medium and large fruit type scion Korean pine is increased, and the proportion of full seeds in cones is improved. The fruit thinning strength in the red pine fruiting period is reduced, and the red pine cones picking efficiency is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of forest cultivation and relates to a method for improving the yield of grafted Korean pine cones and balancing tree vigor in semi-arid areas. Background Art

[0002] The Korean pine (Pinus koraiensis) fruit forest is cultivated by drawing on the experience of seed garden management. In terms of superior tree selection, it is mainly carried out in the Korean pine primary asexual seed garden or Korean pine plantation. The high-yield and strong-bearing superior trees are selected based on the fruit yield and the number of fruit scars, and the medium-yield trees with relatively large pollen are selected. The female superior trees and medium-yield trees are used to establish a bud collection nursery at a ratio of 3:1. In addition, in the place of origin, the male-biased Korean pine individuals have a small fruit yield but a large cone size, while the female-biased individuals have a large fruit yield but a small cone size; individuals of the same sex type can be divided into large-fruit type, medium-fruit type and small-fruit type.

[0003] It can be seen that in the origin of Korean pine, the climate, water and soil conditions are suitable for the growth of Korean pine, and the fruit yield and fruit shape of Korean pine are negatively correlated. Therefore, it is not easy to distinguish large-fruited, medium-fruited and small-fruited Korean pine. There is no unified standard and procedure for how to select medium- and large-fruited scions.

[0004] In semi-arid areas, Pinus sylvestris var. mongolica and Pinus tabulaeformis are the main tree species for afforestation. The management benefits of young forests of Pinus sylvestris var. mongolica and Pinus tabulaeformis are relatively low. Using Pinus sylvestris var. mongolica and Pinus tabulaeformis as rootstocks and grafting them with Korean pine to cultivate nut forests provides a new idea for the management of young forests of Pinus sylvestris var. mongolica and Pinus tabulaeformis.

[0005] The scions used in the Korean pine hybrid fruit forest in semi-arid areas are all imported from the origin of Korean pine. First, using Pinus sylvestris or Pinus tabulaeformis as rootstocks, the scions are grafted to ensure survival; second, the crown growth is ensured through fruit thinning; third, the normal fruiting of Korean pine is achieved through irrigation, weeding, shaping and pruning, pest and disease control and other nurturing measures.

[0006] The scions introduced from the origin of Korean pine are mainly female scions. We found that in normal years, the crowns of grafted trees with large fruit yields are prone to dieback or death in the spring after the fruits mature. This shows that in semi-arid areas, female-biased rootstock saplings are prone to imbalance in vegetative growth and reproductive growth, which leads to a decrease in the stress resistance of Korean pine shoots and their inability to survive the winter naturally, which in turn leads to a decrease in the survival rate of Korean pine grafted saplings, a poor forest appearance, and a decrease in yield.

[0007] Therefore, how to develop a method for improving the cone yield and tree vigor balance of grafted Korean pine in semi-arid areas is an urgent problem that technicians in this field need to solve. Summary of the invention

[0008] In view of this, the present invention provides a method for improving the yield of grafted Korean pine cones and the balance of tree vigor in semi-arid areas. In order to achieve the above object, the present invention adopts the following technical scheme:

[0009] A method for improving the cone yield and tree vigor balance of grafted Korean pine in semi-arid areas comprises the following steps:

[0010] (1) In semi-arid areas, from early April to early May, select fruiting branches with less than 5 to 8 cones from saplings grafted on different rootstocks of Korean pine that are more than 4 years old and in the early stage of fruiting, and evenly retain 2 to 3 one-year-old cones on the fruiting branches;

[0011] (2) From late September to late October, during the period of Korean pine cone maturity, select Korean pine cross-root grafted saplings with a single fruiting branch having a maximum cone length of 12.0-14.0 cm or more from the fruiting branches selected in step (1) as medium-to-large fruiting mother trees;

[0012] (3) From early January to early March of the following year, collect medium-large fruit scions from medium-large fruit scion mother trees and store them at low temperature mixed with ice and snow;

[0013] (4) From mid-to-late April to early May of the following year, select robust branches of Pinus sylvestris or Pinus tabulaeformis as rootstocks and use the nail-shaped multi-bud bagging cleft grafting method for cross-rootstock grafting;

[0014] Alternatively, strong branches of a grafted pine tree with a biased female shape are selected as rootstocks, and the grafting is performed by using a nail-shaped multi-bud bagging cleft grafting method or a pith cambium grafting method. After grafting, the hole is enlarged and watered 1 to 2 times to obtain a grafted pine tree with a biased female shape and a medium-large fruit type scion.

[0015] (5) For grafted gyno-korean pine trees with medium-to-large fruit-bearing scions, the target tree shape should be cultivated and the rootstock should be cut, untied, and shaped and pruned starting in the spring of the following year after the grafting is successful. The medium-to-large fruit-bearing scions on the gyno-korean pine trees should be thinned out in time, leaving 2 to 3 fruits on each fruiting branch.

[0016] Furthermore, in step (1), the rootstock of the Korean pine cross-root grafted sapling is Pinus sylvestris var. mongolica.

[0017] Furthermore, in step (4), the rootstock of the female-biased Korean pine grafted tree is Pinus sylvestris or Pinus koraiensis.

[0018] Furthermore, in step (5), the female Korean pine grafted trees with medium-to-large fruit scions are shaped and pruned into a Y-shape or a happy heart shape according to the target tree shape to be cultivated.

[0019] The present invention also provides an application of the method for improving the cone yield and tree vigor balance of grafted Korean pine in semi-arid areas in bud nursery construction or fruit forest construction.

[0020] The beneficial effects of the present invention are as follows: the prior art mainly uses high-yield and medium-yield Korean pine scions, while the present invention uses medium- and large-fruit scions selected under extreme drought conditions as construction materials for scion nurseries or hetero-rootstock fruit forests.

[0021] The existing technology is based on continuous observation of fruiting amount in normal years, using "average fruiting amount + standard deviation" as the basis for selection. The present invention selects medium and large fruiting scions based on the length of mature cones of Korean pine saplings that bear a small amount of fruit and overwinter normally under extreme drought conditions.

[0022] The prior art is applicable to humid or semi-humid climates. In the origin of Korean pine, with sufficient precipitation and fertile soil as guarantees, even if a large number of fruits are produced, Korean pine will not die back after wintering. The present invention is based on the semi-arid climate. In areas where Korean pine is not suitable for growth, the precipitation is insufficient and fluctuates greatly between years, and it is dry and windy. On the basis of ensuring the preservation rate of Korean pine, the Korean pine can be produced, which is economically superior to the management of artificial young forests of Scots pine or Pinus tabulaeformis.

[0023] The invention is selected under extreme drought conditions, so that the stress resistance of the scion is enhanced, and the preservation rate of Korean pine hetero-rootstock fruit forests in semi-arid areas is improved; the pollen amount of Korean pine in the medium-to-large fruit type scion is increased, and the proportion of full seeds in the cones is increased.

[0024] The annual fruiting branches of Pinus sylvestris or Pinus tabulaeformis grafted trees with medium-large fruit-type scions selected through extreme drought conditions mostly have 3 to 8 cones, and the annual fruiting branches of the female Pinus koraiensis grafted trees mostly have 6 to 13 cones. The present invention reduces the intensity of annual cone thinning during the fruiting period of Pinus koraiensis and improves the efficiency of picking cones of Pinus koraiensis.

[0025] The present invention adopts medium-large fruit type scions to achieve a balance between the yield of Korean pine cones and tree vigor, improve the preservation rate of Korean pine cross-rootstock saplings, and ultimately achieve the goal of stable and high yields. DETAILED DESCRIPTION

[0026] The principles and features of the present invention are described in conjunction with the following embodiments. The examples are only used to explain the present invention and are not used to limit the scope of the present invention.

[0027] Example 1

[0028] The method for improving the cone yield and tree vigor balance of grafted Korean pine in semi-arid areas comprises the following steps:

[0029] (1) From April 27 to May 8, 2023, at the Huangyugou Sand Control and Afforestation Forest Farm in Keshiketeng Banner, Chifeng City, Inner Mongolia Autonomous Region, on 4-year-old Korean pine grafted saplings in the early fruiting stage, the rootstock of the Korean pine grafted saplings was Pinus sylvestris, fruiting branches with less than 8 cones were selected, and 2 to 3 one-year-old cones were evenly retained on the fruiting branches;

[0030] (2) On October 18, 2023, after the Korean pine cones mature, select Korean pine cross-root grafted saplings on the fruiting branches selected in step (1) with the largest cone on the single fruiting branch being 12.0 cm or longer as medium-to-large fruit-bearing mother trees;

[0031] (3) From February 8 to March 6, 2024, collect medium-large fruit scions from medium-large fruit mother trees and store them at low temperature mixed with ice and snow;

[0032] (4) From April 25 to May 9, 2024, sturdy branches of Larix gmelinii with a height of 0.6-1.7 m were selected as rootstocks in Sidaogou, Dongjuziying Forest Area, Wangyedian Experimental Forest Farm, Kalaqin Banner, Chifeng City, and the nail-shaped multi-bud bagging method was used for grafting to establish a mountain-type bud collection nursery without irrigation; on July 4, 2024, the bags were removed.

[0033] Grafting results: According to the survey on July 4, 2024, the survival rate of medium and large fruit type scion grafting was 95.0%.

[0034] The same group of grafting workers grafted female-dominated scions of red pine introduced from Kaiyuan City, Liaoning Province at the state-owned Anqinggou Forest Farm in Songshan District, Chifeng City. They used 2.2-2.5m high Larix gmelinii saplings as rootstocks. After topping, they grafted 2 to 3 scions on 1.7m branches. After grafting, the holes were expanded and watered once. The grafting survival rate was 86.0% as surveyed on September 23, 2024.

[0035] Example 2

[0036] The method for improving the cone yield and tree vigor balance of grafted Korean pine in semi-arid areas comprises the following steps:

[0037] (1) In Zhongxing Village, Dajing Town, Linxi County, Chifeng City, Inner Mongolia Autonomous Region, from May 2 to May 13, 2021, on 6-year-old Korean pine grafted saplings in the early fruiting stage, the rootstock of the Korean pine grafted saplings was Pinus sylvestris, fruiting branches with less than 5 cones were selected, and 2 to 3 one-year-old cones were evenly retained on the fruiting branches;

[0038] (2) On September 28, 2021, after the Korean pine cones mature, select a Korean pine cross-root grafted sapling on a fruiting branch with a maximum cone length of 14.0 cm or more from the fruiting branches selected in step (1) as a large-fruit type budding mother tree;

[0039] (3) From January 5 to January 12, 2022, large-fruit scions were collected from large-fruit mother trees and stored at low temperatures mixed with ice and snow;

[0040] (4) From May 6 to May 13, 2022, in Zhongxing Village, Dajing Town, Linxi County, Chifeng City, Inner Mongolia Autonomous Region, strong branches of gynogenetic Korean pine grafted trees were selected as rootstocks. The rootstock of the gynogenetic Korean pine grafted trees was Pinus sylvestris var. mongolica. The grafting was performed using the pith cambium grafting method. After grafting, the hole was enlarged and watered twice to obtain gynogenetic Korean pine grafted trees with large-fruited scions.

[0041] (5) For grafted pine trees with large-fruit scions, the target tree shape should be cultivated. The pruning should be started from the spring of the following year after the grafting is successful. The grafted pine trees with large-fruit scions should be shaped and pruned into a Y shape according to the target tree shape. The large-fruit scions on the grafted pine trees should be thinned out in time, leaving 2 to 3 fruits on each fruiting branch.

[0042] Grafting results: According to the investigation on July 5, 2024, the survival rate of large-fruit scion grafted trees was 85.5%; in Zhongxing Village, Dajing Town, Linxi County, the same group of workers grafted mainly female scions purchased from Mudanjiang City, Heilongjiang Province from May 1 to May 4, 2022, and the survival rate of grafted trees was 75.1%.

[0043] Example 3

[0044] The method for improving the cone yield and tree vigor balance of grafted Korean pine in semi-arid areas comprises the following steps:

[0045] (1) In Zhongxing Village, Dajing Town, Linxi County, Chifeng City, Inner Mongolia Autonomous Region, from May 2 to May 13, 2021, on 6-year-old Korean pine grafted saplings in the early fruiting stage, the rootstock of the Korean pine grafted saplings was Pinus sylvestris, fruiting branches with less than 5 cones were selected, and 2 to 3 one-year-old cones were evenly retained on the fruiting branches;

[0046] (2) On September 28, 2021, after the Korean pine enters the cone maturity period, select the Korean pine cross-root grafted saplings on the fruiting branches with the largest cone length of 12.0-13.9 cm on the single fruiting branches selected in step (1) as the medium-fruit type budding mother trees;

[0047] (3) From January 5 to January 12, 2022, collect medium-fruiting scions from medium-fruiting mother trees and store them at low temperatures mixed with ice and snow;

[0048] (4) From May 6 to May 13, 2022, in Zhongxing Village, Dajing Town, Linxi County, Chifeng City, Inner Mongolia Autonomous Region, strong branches of gynecological Korean pine grafted trees were selected as rootstocks. The rootstock of the gynecological Korean pine grafted trees was Pinus sylvestris. The grafting was performed using the nail-shaped multi-bud bagging cleft grafting method. Each plant was grafted with 2-3 buds. After grafting, the hole was enlarged and watered once to obtain gynecological Korean pine grafted trees with medium-fruit type scions;

[0049] (5) For grafted gynoecium-dominated Korean pine trees with medium-fruited scions, the target tree shape should be cultivated. The pruning should be started from the year after the grafting is successful. The grafted gynoecium-dominated Korean pine trees with medium-fruited scions should be shaped and pruned into an open-heart shape according to the target tree shape. The medium-fruited scions on the grafted gynoecium-dominated Korean pine trees should be thinned out in time, leaving 2 to 3 fruits on each fruiting branch.

[0050] Grafting results: According to the survey on July 5, 2024, the grafting survival rate of medium-fruit scion was 88.0%; the grafting survival rate of mainly female scion was 75.1%.

[0051] Example 4

[0052] The method for improving the cone yield and tree vigor balance of grafted Korean pine in semi-arid areas is characterized by comprising the following steps:

[0053] (1) At the Huangyugou Sand Control and Afforestation Forest Farm in Keshiketeng Banner, Chifeng City, Inner Mongolia Autonomous Region, from April 27 to May 8, on 4-year-old Korean pine grafted saplings in the early fruiting stage, the rootstock of the Korean pine grafted saplings was Pinus sylvestris, fruiting branches with less than 8 cones were selected, and 2 to 3 one-year-old cones were evenly retained on the fruiting branches;

[0054] (2) On October 18, 2023, after the Korean pine enters the cone maturity period, select the Korean pine cross-root grafted saplings on the fruiting branches selected in step (1) with the largest cone on the single fruiting branch being 12.0 cm or longer as the medium-to-large fruit-bearing mother trees;

[0055] (3) From February 8 to March 6, 2024, collect medium-large fruit scions from medium-large fruit mother trees and store them at low temperature mixed with ice and snow;

[0056] (4) From April 25 to May 9, 2024, sturdy branches of Pinus tabulaeformis with a height of 1.5-2.2 m were selected as rootstocks in the Gushan Forestry Area of ​​Wangyedian Experimental Forest Farm in Kalaqin Banner, Chifeng City. The nail-shaped multi-bud bagging method was used for grafting, with 1 to 4 scions grafted per plant to build a nut forest. Because it rained once during the grafting period, no watering was done after grafting; on July 4, the bags were removed.

[0057] Grafting results: According to the survey on July 4, 2024, the survival rate of medium and large fruit type scion grafting was 90.5%.

[0058] The same group of grafting workers grafted female-dominated scions of red pine introduced from Kaiyuan City, Liaoning Province at the state-owned Anqinggou Forest Farm in Songshan District, Chifeng City. They used 2.2-2.5m high Larix gmelinii saplings as rootstocks. After topping, they grafted 2 to 3 scions on 1.7m branches. After grafting, the holes were expanded and watered once. The grafting survival rate was 86.0% as surveyed on September 23, 2024.

[0059] The specific operations of the pith cambium grafting method and the nail-shaped multi-bud bagging cleft grafting method of the present invention are shown in: Chifeng Local Standard DB1504 / T 1040-2024 Technical Regulations for Korean Pine Different Rootstock Grafting.

[0060] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for improving the yield and tree vigor balance of grafted Korean pine cones in semi-arid areas, characterized in that: The following steps are involved: (1) In semi-arid areas, from early April to early May, select fruiting branches with less than 5-8 cones from saplings grafted on different rootstocks of Korean pine that are grafted for more than 4 years and are in the early stage of fruiting, and evenly retain 2-3 one-year-old cones on the fruiting branches; (2) From late September to late October, during the period of Korean pine cone maturity, select Korean pine cross-root grafted saplings with a single fruiting branch having a maximum cone length of 12.0-14.0 cm or more from the fruiting branches selected in step (1) as medium-to-large fruiting mother trees; (3) From early January to early March of the following year, collect medium-large fruit scions from medium-large fruit scion mother trees and store them at low temperature mixed with ice and snow; (4) From mid-to-late April to early May of the following year, select robust branches of Pinus sylvestris or Pinus tabulaeformis as rootstocks and use the nail-shaped multi-bud bagging cleft grafting method for cross-rootstock grafting; Alternatively, strong branches of a grafted pine tree with a biased female shape are selected as rootstocks, and the grafting is performed by using a nail-shaped multi-bud bagging cleft grafting method or a pith cambium grafting method. After grafting, the hole is enlarged and watered 1 to 2 times to obtain a grafted pine tree with a biased female shape and a medium-large fruit type scion. (5) For grafted gyno-korean pine trees with medium-to-large fruit-bearing scions, the target tree shape should be cultivated and the rootstock should be cut, untied, and shaped and pruned starting in the spring of the following year after the grafting is successful. The medium-to-large fruit-bearing scions on the gyno-korean pine trees should be thinned out in time, leaving 2 to 3 fruits on each fruiting branch.

2. A method for improving the yield and tree vigor balance of grafted Korean pine cones in semi-arid areas according to claim 1, characterized in that: In step (1), the rootstock of the Korean pine cross-root grafted sapling is Pinus sylvestris var. mongolica.

3. A method for improving the yield and tree vigor balance of grafted Korean pine cones in semi-arid areas according to claim 1, characterized in that: In step (4), the rootstock of the female-biased Korean pine grafted tree is Pinus sylvestris or Pinus koraiensis.

4. A method for improving the yield and tree vigor balance of grafted Korean pine cones in semi-arid areas according to claim 1, characterized in that: In step (5), the female Korean pine grafted trees with medium-to-large fruit-shaped scions are shaped and pruned into a Y-shape or a happy heart shape according to the target tree shape.

5. Use of the method for improving cone yield and tree vigor balance of grafted Korean pine in semi-arid areas as described in any one of claims 1 to 4 in bud nursery construction or fruit forest construction.