Method for improving clone improved variety breeding efficiency of toona sinensis and toona ciliata

Abstract

The invention discloses a method for improving clone improved variety breeding efficiency of toona sinensis and toona ciliata, and belongs to the technical field of forest clone breeding. The method comprises the following steps: (1) screening high-standard superior trees or super seedlings; (2) asexual propagation: performing asexual propagation on the screened high-standard superior trees or super seedlings to propagate superior tree or super seedling clonal seedlings; and (3) clone improved variety breeding: constructing a clone determination forest by using the bred clone seedlings of high-standard superior trees or super seedlings, and screening clone improved varieties of cedrela sinensis and toona ciliata from the clone determination forest which is 4 years old to obtain clone improved varieties of cedrela sinensis and toona ciliata. According to the method, high-standard superior tree and super seedling selection is combined with short-period clone improved variety breeding, the breeding workload is small, the period is short, and the clone breeding efficiency and the clone genetic gain are greatly improved.

Description

Technical Field

[0001] This invention belongs to the field of asexual reproduction breeding technology of forest trees, specifically relating to a method for improving the efficiency of asexual reproduction breeding of Toona sinensis and Toona sinensis. Background Technology

[0002] Chinese toon ( Toona sinensis ), Red Toon ( Toona ciliata All of them are deciduous or semi-deciduous trees of the Toona genus in the Meliaceae family. They have straight trunks, grow rapidly, and their wood is yellowish-brown to reddish-brown with beautiful grain. They can be used to make high-end furniture and are listed as fast-growing and precious timber species in my country and national reserve forest species.

[0003] Chinese toon (Toona sinensis) has a very wide distribution and underwent large-scale afforestation from 2000 to 2013. Red toon (Toona sinensis var. rubra) is a national second-class protected wild plant, mainly existing as wild resources, with limited artificial afforestation. In existing Chinese toon and red toon stands, individual differentiation is quite severe, with significant differences in growth between individual trees, resulting in uneven forest stands and low stand quality. Therefore, conducting clonal breeding of superior varieties of Chinese toon and red toon is crucial for improving stand quality and yield.

[0004] Current research on the breeding of superior clones mainly follows two approaches: One approach is to select superior trees in the forest stand → propagate clonal seedlings → conduct clonal testing → select superior clonal lines. For example, in the case of black acacia, superior trees with a diameter at breast height greater than 20% and a tree height greater than 15% are selected in the forest stand, and superior clonal seedlings are propagated. Superior clonal lines are then selected through clonal testing.

[0005] Another approach is to collect superior tree seeds to propagate half-sib family seedlings, or to obtain full-sib family seedlings through hybridization breeding. Then, super seedlings are selected from these family seedlings. By propagating the selected super seedlings into asexual seedlings, asexual lines with high propagation efficiency are screened out and then asexual line testing is conducted for asexual line breeding.

[0006] Secondly, regarding the time required for clonal breeding, both Chinese toon and red toon are fast-growing timber species with a minimum rotation period of 18 years. According to the current industry standard "Specifications for the Approval of Improved Tree Varieties" (GB / T 14071-2025), the breeding cycle for improved varieties of fast-growing tree species should be no less than half the rotation period. Therefore, the clonal breeding time for Chinese toon and red toon requires at least 9 years. Whether clonal breeding is carried out through propagation of superior tree clones or super seedling clones, the key technical issue facing clonal breeding is whether it is possible to select superior clones with high genetic gain in a short period of time.

[0007] Therefore, finding a method to improve the efficiency of clonal breeding of Toona sinensis and Toona sinensis is the key to shortening the clonal breeding cycle and improving the efficiency of clonal breeding. SUMMARY

[0008] In order to solve the above problems in the prior art, the present application provides a method for improving the selection efficiency of good clones of Toona sinensis and T. sinensis var. purpurea, which can directly select good clones of T. sinensis and T. sinensis var. purpurea from 4-year-old clones in a forest.

[0009] To achieve the above object, the technical scheme adopted by the present application to solve its technical problem is: The object of the present application is to provide a method for improving the selection efficiency of good clones of T. sinensis and T. sinensis var. purpurea, which comprises the following steps: (1) Screening of high-standard superior trees or super seedlings S1, Screening of high-standard superior trees In a T. sinensis or T. sinensis var. purpurea stand of 2-year-old young forest and above, high-standard superior trees are selected with a diameter at breast height (DBH) of ≥40% and a tree height of ≥15% of the average value of the stand; S2, Screening of super seedlings The 1-year-old half-sib family seedlings of T. sinensis or T. sinensis var. purpurea are screened for super seedlings by using the mean value ± 2-3 times the standard deviation for both ground diameter and seedling height; the super seedlings are replanted for 1 year, and then the replanted super seedlings are reselected with a DBH of ≥40% and a seedling height of ≥30% to obtain high-standard super seedlings; Generally, super seedlings are used for clone selection, and the super seedlings are directly propagated to obtain clone seedlings for clone determination. The number of clones participating in clone determination is large, the workload of seedling propagation and post-planting management is large, and the proportion of clones that can be selected as good clones in the later stage is small.

[0010] (2) Vegetative propagation The high-standard superior trees or high-standard super seedlings obtained by screening are vegetatively propagated to obtain clone seedlings of the high-standard superior trees or high-standard super seedlings; (3) Selection of good clones The clone seedlings of the high-standard superior trees or high-standard super seedlings are used to construct a clone determination forest, and good clones of T. sinensis and T. sinensis var. purpurea are selected from the 4-year-old clone determination forest.

[0011] For the selection standard of superior trees, the general selection standard of superior trees is a DBH of greater than 20% and a tree height of greater than 15%. The selection standard of superior trees is relatively low, the number of clones participating in clone determination is relatively large, the workload of selection is relatively large, the genetic gain of part of the superior tree clones after afforestation is limited, and the probability of becoming a good clone after afforestation is not high.

[0012] As for the number of times of selecting superior trees, the application only needs to be selected once, and the time only needs one year, which greatly shortens the time of selecting superior trees, and is equivalent to improving the efficiency of clone breeding in time. The application selects high-standard superior trees with a diameter of more than 40% and a height of more than 15%, which not only reduces the workload of clone seedling propagation and regional test afforestation, but also greatly improves the genetic gain of the selected superior tree clone after afforestation, and greatly improves the probability of becoming a clone variety after afforestation, which is equivalent to improving the efficiency of clone breeding in quality.

[0013] The application shortens the time of clone variety breeding of Toona sinensis and Toona ciliata to 4 years, which is 5 years earlier than the time (9 years) specified by the industry standard, and greatly improves the efficiency of clone breeding.

[0014] Further, step S1 is performed in a high-standard superior tree selection in a 5-year-old Toona sinensis and a 2-year-old Toona ciliata young forest.

[0015] Further, the process of step S2 is: The selected 1-year-old super seedlings of Toona sinensis and Toona ciliata are planted on forest land with consistent site conditions, with a plant spacing of 0.5m*0.5m, and the trunk is cut at a distance of 10cm from the ground after planting. The same management measures are adopted in the later period, and the ground diameter and seedling height of all super seedlings are investigated after 1 year. The super seedlings are reselected according to the standard of diameter ≥40% and height ≥30%, and the selection rate is not higher than 15%.

[0016] The application reselects the selected super seedlings according to the high standard of diameter ≥40% and height ≥30% at the time of afforestation for 1 year, and controls the reselection rate within 15%, which not only reduces the selection link and time, but also reduces the workload of clone seedling propagation and regional test afforestation. The genetic gain of the selected superior tree clone after afforestation is very high, and the probability of becoming a clone variety after afforestation is greatly improved, which is equivalent to improving the efficiency of clone variety breeding in quality.

[0017] Further, in step (2), the clone is propagated by cuttage, root propagation or tissue culture.

[0018] Further, in step (2), the superior tree or super seedling clone with more than 90 seedlings is used for clone variety breeding.

[0019] Further, in step (3), the establishment process of the clone test forest is as follows: The clone seedlings of the high-standard superior trees or high-standard super seedlings are established in a clone test forest in 3-4 different ecological points in the suitable area of Toona sinensis and Toona ciliata, all of which adopt 10 plant plots with 3 repetitions. The local main variety of Toona sinensis and Toona ciliata is used as a control, and Toona sinensis adopts a plant spacing of 2m*3m, and Toona ciliata adopts a plant spacing of 3m*4m.

[0020] Further, the test forest adopts the same management measures, and after afforestation, 1-3 years, 3 times of weeding, 1 time of topdressing, 1 time of pruning and removing sprouts every year; 1-2 times of weeding and 1 time of pruning and shaping every year starting from the 4th year; 1000g per plant per year for 2 consecutive years of formula fertilization from the 7th to 8th year; and timely monitoring and disease and pest control according to the actual situation every year.

[0021] Further, the topdressing amount every year from 1 to 3 years is as follows: 200g in the first year, 250g in the second year and 500g in the third year.

[0022] The beneficial effects of the present application are as follows: The present application selects high-standard superior trees with a diameter at breast height ≥40% and a tree height ≥15% in young forest of Chinese toona and red toona, or selects super seedlings from superior tree half-sib family seedlings, and 1-year reselection of super seedlings with a diameter at breast height ≥40% and a tree height ≥30% high standard; after asexual reproduction, asexual clone determination can be carried out at 4 years old. The selection time of superior trees and super seedlings is reduced, the quality of superior trees and super seedlings is improved, the workload of asexual clone breeding in the later stage is reduced, the efficiency of asexual clone breeding is improved, the cycle of asexual clone breeding is greatly shortened, and the problems of long cycle and low efficiency of asexual clone breeding of Chinese toona and red toona are solved.

[0023] The method of the present application uses high-standard superior trees or super seedlings to reproduce asexual clone seedlings for asexual clone breeding, and combines the method of short-cycle asexual clone breeding, which has small breeding workload, short cycle, and greatly improves the efficiency of asexual clone breeding and the genetic gain of asexual clone. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 The growth comparison chart of 1-8 years of asexual clone breeding of Chinese toona and the control (back row) in the same place of Pengxi is shown. DETAILED DESCRIPTION

[0025] The specific embodiments of the present application are described below to facilitate understanding of the present application by those skilled in the art, but it should be clear that the present application is not limited to the scope of the specific embodiments, and for those skilled in the art, it is obvious that various changes are within the spirit and scope of the present application defined and determined by the appended claims, and all the inventions utilizing the concept of the present application are within the scope of protection.

[0026] Example 1 1. High-standard superior tree selection 1) Superior tree selection tree age According to the results of early and late correlation analysis of Toona sinensis and T. surensis superior trees, the diameter at breast height, tree height and single tree volume of T. sinensis superior trees have extremely significant positive correlation in 5-8 years, so the diameter at breast height and single tree volume can be used as the main indexes for superior tree selection in 5-year-old young forest; the diameter at breast height, tree height and single tree volume of T. surensis superior trees have extremely significant positive correlation in 2-10 years, so the diameter at breast height and tree height can be used as the main indexes for superior tree selection in 2-year-old young forest and above.

[0027] Table 1 Early and late correlation analysis of 2-8-year-old T. sinensis superior trees in Pengxi

[0028] Table 2 Early and late correlation analysis of 2-10-year-old T. surensis growth

[0029] 2) High-standard superior tree selection criteria According to the existing clonal determination results, in addition to the basic criteria of selecting healthy growth, straight trunk and small side branches, the high-standard superior tree selection criteria of T. sinensis and T. surensis are as follows: the proportion of diameter at breast height ≥ 40% and tree height ≥ 15% of the average value of the stand for superior tree selection. The superior trees selected by this high-standard method are used to breed clonal seedlings for clonal breeding, which has a higher probability of breeding clonal varieties and higher volume gain in the later period.

[0030] Table 3 Growth of 2 T. sinensis superior trees selected as clonal varieties

[0031] 2) High-standard super seedling selection 1) Super seedling primary selection The mean value ± 2-3 times the standard deviation method is used to select super seedlings for 1-year-old half-sib family seedlings of T. sinensis and T. surensis.

[0032] 2) High-standard super seedling reselection The selected 1-year-old super seedlings of T. sinensis and T. surensis are planted in forest land with consistent site conditions, with a plant spacing of 0.5m x 0.5m. After planting, the stems are cut at 10cm from the ground, and the same management measures are adopted in the later period. After 1 year, the ground diameter and height of all super seedlings are investigated, and the super seedlings are reselected according to the criteria of diameter at breast height ≥ 40% and height ≥ 30%. The selection rate should not be higher than 15%. The high-standard super seedlings selected by this standard are used to breed clonal seedlings for clonal breeding, which has a smaller workload, a higher probability of breeding clonal varieties and higher volume gain.

[0033] 3) Vegetative reproduction The selected high-standard superior trees or high-standard super seedlings are propagated asexually using various methods such as cutting propagation, root propagation, or tissue culture. The asexual lines of the high-standard superior trees or high-standard super seedlings that produce more than 90 seedlings are used for the selection and breeding of superior asexual varieties.

[0034] 4. Clone determination 1) Clonal testing forest establishment For the high-standard superior trees or high-standard super seedlings propagated from clonal seedlings, clonal testing forests were established at 3-4 different ecological sites in the suitable growing areas of Chinese toon and red toon. Each plot used 10 trees and 3 replicates. The local main varieties of Chinese toon and red toon were used as controls. The spacing between Chinese toon was 2m×3m and the spacing between red toon was 3m×4m.

[0035] 2) Experimental forest management The experimental forest adopted the same management measures. For the first 1-3 years after afforestation, weeding was carried out 3 times a year, topdressing was applied once a year (200g, 250g, and 500g per year for the first, second, and third years, respectively), and pruning and removing sprouts were done once a year. Starting from the fourth year, weeding was carried out 1-2 times a year, and pruning and shaping were done once a year. For the 7th and 8th years, formula fertilizer was applied for 2 consecutive years, with 1000g per tree per year. Pests and diseases were monitored and controlled in a timely manner according to the actual situation each year.

[0036] 5. Selection and breeding of superior clones 1) Breeding of superior clonal varieties of Toona sinensis Chinese toon is an early-growing fast-growing tree species. Correlation analysis of early-toon clones from 4 to 8 years showed a significant positive correlation between 8-year-old and 4-year-old Chinese toon clones in terms of diameter at breast height (DBH), tree height, and single-tree volume. Furthermore, a highly significant positive correlation was found between 8-year-old and 5-8-year-old Chinese toon clones in these same parameters. Therefore, the earliest suitable clonal variety can be selected and bred from 4-year-old clone testing forests. The superior clonal variety 'Shu Chun No. 1' bred in Pengxi (see...) Figure 1 A good example is the growth pictures of 'Shuchun No. 1' from 1 to 8 years and the control group, which show that the growth advantage of the actual clonal superior variety is evident in the first year of afforestation. The 8-year-old control group had an average diameter at breast height of 10.2 cm, an average tree height of 10.4 m, and a single tree volume of 0.0455 m². Figure 1 Among them, the 8-year-old 'Shuchun No. 1' has a diameter at breast height of 15.6cm, a tree height of 16.7m, and a single tree volume of 0.1592m³. 3 The increases in diameter at breast height (DBH), tree height, and single-tree volume were 52.9%, 60.6%, and 249.9%, respectively. The superior clone of 'Shuchun No. 1' was propagated from high-standard superior trees selected from 5-year-old Chinese toon stands, and its corresponding number is GX16 (Table 3).

[0037] 2) Breeding of superior clonal varieties of Toona sinensis The redtoon also belongs to the early fast-growing tree species. According to the early and late correlation analysis results of the redtoon clone 4-8 years, the diameter, height and single tree volume of the 8-year-old redtoon clone are in a very significant positive correlation with the 4-year-old redtoon clone. Therefore, the clone breeding can be determined from the 4-year-old clone in the forest.

[0038] Therefore, the clone breeding time of the Chinese toon and the redtoon can be shortened to 4 years.

[0039] Table 4 Early and late correlation analysis of the Pengxi Chinese toon clone 2-8 years

[0040] Table 5 Early and late correlation analysis of the Luxian redtoon clone 2-8 years

[0041] Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solutions of the present application and are not limiting. Although the present application is described in detail with reference to the examples, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present application, and they should be covered in the scope of the claims of the present application.

Claims

1. A method for improving the efficiency of clonal breeding of Toona sinensis and Toona sinensis, characterized in that, Includes the following steps: (1) Select high-standard superior trees or super seedlings S1, High-Standard Excellent Tree Selection In Chinese toon and red toon forests with 2-year-old saplings and above, high-standard superior trees are selected based on the average stand value of diameter at breast height ≥40% and tree height ≥15%. S2, Super Seedling Screening For one-year-old half-sib seedlings propagated from superior Toona sinensis and Toona sinensis seeds, super seedlings were selected by using the mean ± 2-3 times standard deviation for both ground diameter and seedling height. One year after the selected super seedlings were planted, they were re-selected for super seedlings based on the standard of ≥40% diameter at breast height and ≥30% seedling height, and high-standard super seedlings were selected. (2) Asexual reproduction The selected high-standard superior trees or high-standard super seedlings are propagated asexually to produce asexual seedlings of high-standard superior trees or high-standard super seedlings. (3) Selection and breeding of superior clonal varieties Clonal testing forests were constructed using high-standard superior trees or high-standard super seedlings propagated from clonal lines. Superior clonal varieties of Toona sinensis and Toona sinensis were selected from the 4-year-old clonal testing forests.

2. The method according to claim 1, characterized in that, The process of step S2 is as follows: The selected one-year-old super seedlings of Chinese toon and red toon were planted on forest land with consistent site conditions, with a plant spacing of 0.5m × 0.5m. After planting, the trunks were cut off 10cm from the ground. The same management measures were adopted in the later stage. One year later, the ground diameter and seedling height of all super seedlings were investigated. Super seedlings were re-selected based on the standard of diameter at breast height ≥ 40% and seedling height ≥ 30%, with the selection rate not exceeding 15%.

3. The method according to claim 1, characterized in that, In step (2), asexual reproduction is carried out through cutting propagation, root propagation, or tissue culture.

4. The method according to claim 1, characterized in that, In step (2), the superior trees or super seedlings that have produced more than 90 seedlings are used for the selection and breeding of superior clonal varieties.

5. The method according to claim 1, characterized in that, The process of establishing the clonal testing forest in step (3) is as follows: For the high-standard superior trees or high-standard super seedlings propagated from clonal seedlings, clonal testing forests were established at 3-4 different ecological sites in the suitable growing areas of Chinese toon and red toon. Each plot used 10 trees and 3 replicates. The local main varieties of Chinese toon and red toon were used as controls. The spacing between Chinese toon was 2m×3m and the spacing between red toon was 3m×4m.

6. The method according to claim 5, characterized in that, The experimental forest adopted the same management measures. For the first 1-3 years after afforestation, weeding was carried out 3 times a year, topdressing was applied once a year, and pruning and removing sprouts was done once a year. Starting from the fourth year, weeding was carried out 1-2 times a year, and pruning and shaping were done once a year. Weeding was carried out 1-2 times a year thereafter. For the 7th and 8th years, formula fertilizer was applied for 2 consecutive years, 1000g per tree per year. Pests and diseases were monitored and controlled in a timely manner according to the actual situation each year.

7. The method according to claim 6, characterized in that, The amount of fertilizer applied annually for 1-3 years is as follows: 200g in the first year, 250g in the second year, and 500g in the third year.

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