LU102263B1

LU102263B1 - A Method for Shortening the Juvenile Span by Grafting Pear Hybrid Seedling to the Rootstock of the Same Species

Info

Publication number: LU102263B1
Application number: LU102263A
Authority: LU
Inventors: Shaoling Zhang; Kaijie Qi; Zhihua Xie
Original assignee: Univ Nanjing Agricultural
Priority date: 2020-12-07
Filing date: 2020-12-07
Publication date: 2021-06-07

Abstract

This invention discloses a method for shortening the juvenile span by grafting the terminal bud of pear hybrid seedling to the rootstock of the same species. This method includes the following steps: (1) Scion preparation: collecting a plump bud 20-30cm below the top of the central trunk of a 2-year-old hybrid seedling as the scion. (2) Stock preparation: cutting the hybrid seedling horizontally at the lower part of the trunk base at 10-15cm from the ground as the stock. (3) Grafting: grafting the collected scion directly to the rootstock of the same species by cleft grafting. (4) Bandaging: bandaging all cuts tightly with plastic film. The height of the bearing position (i.e., the juvenile span) of the hybrid seedling can be reduced by more than 1.2m by this method. The decrease of the overall height of the tree can not only enhance the wind resistance of seedlings, prevent tree lodging, branch breaking and fruit dropping, but also facilitate the field operations such as fruit thinning, bagging, pruning and so on, and reduce the manpower for field management of hybrid seedlings.

Description

Description HU102263 A Method for Shortening the Juvenile Span by Grafting Pear Hybrid Seedling to the Rootstock of the Same Species

Technical Field

This invention relates to a method for shortening the juvenile span by grafting the terminal bud of hybrid seedling to the rootstock of the same species, which is especially suitable for breeding excellent and new varieties from a large number of hybrid seedlings in the conventional cross breeding of pear.

This method is also suitable for the management of hybrid seedlings and the breeding of new and excellent varieties in the cross breeding of other Rosaceae fruit trees.

Background Technology

The innovation ability of fruit tree germplasm resources, the number of high-quality new varieties being bred and the germplasm exploiting of characteristic fruit trees will determine the competitive edges of Chinese fruits and their products in the international market, and is also one of the key factors for the sustainable development of fruit production.

Pear is the third largest fruit tree in China, which is loved by people.

It is also a traditional fruit for export to earn foreign exchange.

There are many kinds and varieties of pear, which can be cultivated in different ecological regions.

Pear trees are cultivated in all provinces (cities and districts) except Hainan Province.

By the end of 2009, China's pear cultivation area was 1.0745 million hm2 with a total output of 13.5381 million tons, accounting for 62% and 64% of the world's pear cultivation area and total output respectively, making China the largest pear producing country in the world.

For more than half a century, especially in the past 20 years, China has made great progress in the cultivation and introduction of pear varieties, and has bred new varieties with independent intellectual property rights and international competitiveness, such as ‘Zaosu’, ‘Huangguan’, ‘Zhongli No.1’, ‘Hongxiangsu’, ‘Cuiguan’. With the implementation of the reform and opening-up policy, many excellent and new varieties suitable for China's climate conditions have been introduced from Japan, South Korea, Europe and the United States, such as “Whangkeumbae’, ‘Niitaka’, “Wonhuwang’, ‘Hosui’, ‘Red Comiss’, ‘Bartlett’. These excellent varieties have been gradually extended and popularized, and played an important role in the renewal and improvement of China's pear varieties.

However, compared with other advanced pear producing countries, China still lags behind in the aspects of variety renewal, fruit quality and participation in international fruit market competition.

The composition of the existing pear varieties obviously lags behind the demand of production and development, which is mainly reflected in the facts that the proportion of late maturing varieties among the main varieties is too large (about 55%), and the proportion of early maturing varieties by area is too small (less than 20%); there are many

1 traditional local varieties but relatively few new excellent varicties. In some areas, the LU102263 problem of variety aging is serious, and the market share declines rapidly. With China's entry into WTO, if we do not have new pear varieties with independent intellectual property rights, it will be very disadvantageous for the development of export-oriented pear industry. In this situation, in order to enhance the competitiveness of China's pear in the international fruit market, independent innovation is a must for constantly launching new excellent pear varieties with distinctive characteristics in cultivation characters and fruit quality traits which meet the needs of the market for industrial use.

Based on the above analysis, the breeding of early maturing, high quality and high resistance new varieties is the key direction of current pear breeding research work, and also the first task to enhance the competitiveness of China's pear in the international and domestic markets. However, conventional cross breeding is still one of the most important methods in the cultivation of new pear varieties, that is, seeds are obtained in the year of cross pollination and are sown in the next year to breed a number of hybrid seedlings. After the hybrid seedlings bear fruit, new excellent varieties are selected and bred according to the fruit quality traits.

Juvenile phase is a period of growth and development before the fruit tree seedling has the ability to form flower bud. Once the juvenile phase is over, the fruit tree has the ability to blossom. The turning point of pear hybrid seedling from juvenile phase to adult phase occurs at a certain space height on the crown, and the branch length from such turning point to the root collar is called juvenile span. The results show that there is a high correlation between juvenile span and juvenile phase. In a certain range, the lower the juvenile span of the seedling, the shorter the juvenile phase, the earlier the flowering and fruiting. In the conventional cross breeding of fruit trees, the method of more combinations of small groups or less combinations of large groups is usually used to ensure a certain number of hybrid seedlings for breeding new varieties. Due to the shortage of land resources and the increasing cross bred population year by year, the density of planted hybrid seedlings is usually large. At the end of juvenile phase, the plant height of the hybrid seedlings under normal conditions is generally 3-4m, and the juvenile span is generally 2-2.5m. The over high flowering and fruiting position due to this biological characteristic and the high planting density bring great inconvenience to the field management and superior plant selection in the later stage, resulting in that bagging, picking and other works all need tools, which are time-consuming and laborious. An overlong juvenile span also causes oversized plant and thus poor wind resistance, easy fruit dropping after bearing or branch lodging, breaking, leading to low space utilization. Therefore, there is an urgent need now for a method to reduce the height of the bearing position.

Invention Summary The purpose of this invention is to provide a method for shortening the juvenile span by grafting the terminal bud of pear hybrid seedling to the rootstock of the same species against 2 the deficiency of the prior art. LU102263 The invention is implemented by the following technical scheme: The method for shortening the juvenile span by grafting the terminal bud of pear hybrid seedling to the rootstock of the same species, which takes the following steps: (1) Scion preparation: collecting a plump bud 20-30cm below the top of the central trunk of a 2-year-old hybrid seedling as the scion. (2) Stock preparation: cutting the trunk of the hybrid seedling horizontally at 10-15cm from the ground and keep the base as the stock. (3) Grafting: grafting the collected scion directly to the described stock by cleft grafting. (4) Bandaging: bandaging all cuts tightly with plastic film.

The age of the described hybrid seedling is 2-year-old and the height is more than 150 cm.

The described scion and stock are both from the same seedling, and the grafting joint is 10-15cm away from the ground.

The beneficial effects of this invention are as follows: At the end of the juvenile phase of the seedling under normal conditions, its plant height is about 3.5-4m and the juvenile span is about 2-2.5m. The biological characteristics of flowers and fruits being too far from the ground have caused many inconveniences in breeding and field production management. After treatment by using this invention, the lowest position of flowering and fruiting is only about 90cm away from the ground. Therefore, it has the following beneficial effects:

1. It reduces the height of the bearing position. Typically, ladder and other tools are needed for field operations such as bagging and picking. However, by using this invention, it is not necessary to use fixing support or prepare other grafting stock, so that manpower and material resources for field management are reduced, the cost is saved, and the efficiency is improved.

2. It reduces the plant height. The hybrid seedling grown under normal conditions is thin and long, which makes it vulnerable to wind damage. After fruit bearing, the weight imbalance between the upper and lower parts of the tree easily causes lodging and breaking of branches, and easily causes fruit dropping or fruit surface abrasion. By using this invention, the plant height of hybrid seedling can be reduced by 1-2m, which enhances the wind resistance and solves the above problems fundamentally.

3. It improves the lighting and ventilation conditions in the field, reduces the covering area of a single seedling, and increases the land use efficiency. The plant height is reduced, the number and length of seedling branches are reduced, the mutual shielding between branches is prevented, therefore, the ventilation and lighting conditions in the field are improved, and the land resources are saved.

Detailed Description of the Presently Preferred Embodiments

1. By using this method, the best implementation time is in spring when the height of a 2-year-old pear tree is 150cm or higher than 150cm, but it can be implemented in autumn if 3 the tree height is less than 1.5 m. The hybrid combination “Jimi x Fengyue” of 2006 was LU102263 taken as an example in this invention.

2. Implementation steps (1) Scion preparation: on March 10 in Nanjing, a 2-year-old pear seedling with a height about 180cm was selected and cut with pruning shears at a position 20cm below the top. A plump bud without disease was carefully selected from the cut branches as the scion for later use.

(2) Juvenile shorting and stock preparation: the sprouts at the base of the seedling were removed, and then the seedling with top removed in (1) was cut horizontally at a position 15cm above the ground surface as the stock.

(3) Grafting: the scion was grafted to the stock by cleft grafting. Care should be taken to align the scion cambium with the stock cambium.

(4) Bandaging: all joints and cuts were bandaged tightly with 2em wide plastic film to prevent water loss.

3. Fruit bearing After treatment by this method, the plant height was about 2.1m and the juvenile span was about 0.9m at the end of the juvenile phase, that is, the lowest flowering and fruiting position was only about 90cm away from the ground. In contrast, the plant height of the seedling grown under normal conditions (control) was about 3-4m and the juvenile span was about 2-2.5m at the end of juvenile phase, which meant that the lowest flowering and fruiting position was only about 2-2.5m away from the ground.

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Claims

Claims LU102263

1. The method for shortening the juvenile span by grafting the terminal bud of pear hybrid seedling to the rootstock of the same species is characterized by taking the following steps: (1) Scion preparation: collecting a plump bud 20-30cm below the top of the central trunk of a 2-year-old hybrid seedling as the scion. (2) Stock preparation: cutting the trunk of the hybrid seedling horizontally at 10-15cm from the ground and keep the base as the stock. (3) Grafting: grafting the collected scion directly to the described stock by cleft grafting. (4) Bandaging: bandaging all cuts tightly with plastic film.

2. The method for shortening the juvenile span by grafting the terminal bud of pear hybrid seedling to the rootstock of the same species according to Claim 1 is characterized in that the age of the hybrid seedling is 2 years, and the tree height is more than 150 cm.

3. The method for shortening the juvenile span by grafting the terminal bud of pear hybrid seedling to the rootstock of the same species according to Claim 1 is characterized in that the scion and stock are both from the same hybrid seedling, and the grafting joint is 10-15cm away from the ground.