A hybridization breeding method for a strong winter-growing Chinese cabbage-type winter rapeseed self-compatibility line.
Through hybridization and multiple generations of backcrossing selection, a strong winter-type Chinese cabbage-like self-compatibility line, LRWCOM-12, was bred, which solved the problem of poor variety stability of winter rapeseed in northern China. This achieved the breeding of varieties with high compatibility and excellent agronomic traits, and laid the foundation for the utilization of heterosis in winter rapeseed in northern China.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-08-11
- Publication Date
- 2026-03-13
AI Technical Summary
The winter rapeseed varieties with strong winter-hardy characteristics, such as Chinese cabbage, planted in cold northern regions are self-incompatible, resulting in varietal mixing, poor stability, short service life, and difficulty in achieving quality improvement and utilizing hybrid vigor.
Through hybridization breeding, the self-compatible winter rapeseed variety Ganza 1 was crossed with the self-incompatible winter rapeseed variety Longyou 7, which is of the strong winter type. After multiple generations of backcrossing and self-selection, a self-compatible strong winter rapeseed self-compatibility line LRWCOM-12 was bred.
A self-compatible and stable winter rapeseed line, LRWCOM-12, was successfully bred, solving the problems of rapid variety degeneration and poor stability. This has enabled the breeding of a winter rapeseed variety with high compatibility and excellent agronomic traits, laying the foundation for the utilization of heterosis in northern winter rapeseed.
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Abstract
Description
[0001] This application is a divisional application. The original application has the application number 202311006867.3, the application date is August 11, 2023, and the invention title is: A method for breeding a self-compatible line of winter rapeseed of the strong winter-growing type. Technical Field
[0002] This invention relates to the field of breeding technology, and in particular to a hybridization breeding method for a strong winter-growing Chinese cabbage-type winter rapeseed self-compatible line. Background Technology
[0003] Winter rapeseed of the Chinese cabbage type possesses characteristics such as cold resistance and early maturity, playing an important role in agricultural production in cold and arid regions of northern China. However, the main varieties cultivated in production are self-incompatible cross-pollinated varieties, i.e., hybrid varieties with high heterogeneity. Self-incompatibility easily leads to varietal mixing, poor varietal stability, and a short service life.
[0004] Therefore, breeding self-compatible varieties is an effective way to improve the quality of winter rapeseed of the strong winter-growing type in northern China, and to increase yield and economic benefits by utilizing heterosis. It is also the key to solving the problem of self-pollination depression in offspring and homozygous parents in quality breeding and the utilization of heterosis. Summary of the Invention
[0005] The purpose of this invention is to provide a method for breeding a strong winter-type Chinese cabbage-like winter rapeseed self-compatible line, so as to transform the self-incompatible winter rapeseed of northern China into a self-compatible one, and to provide a foundation for breeding pure-line varieties, using pure-line parents to solve the bottleneck of the breeding of three-line hybrids of Chinese cabbage-like winter rapeseed, and to significantly increase the yield of Chinese cabbage-like winter rapeseed.
[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution:
[0007] This invention provides a method for breeding a self-compatible line of winter rapeseed of the Chinese cabbage type, comprising the following steps:
[0008] (1) Using the self-compatible winter rapeseed variety Ganza 1 as the female parent and the strong winter rapeseed variety Longyou 7 as the male parent, hybridization was carried out to obtain the F1 generation;
[0009] (2) Using F1 generation plants as the female parent and Longyou 7, a self-incompatible variety of winter rapeseed with strong winter-growing Chinese cabbage type, as the recurrent parent, backcrossing was carried out to obtain BC1F1 generation.
[0010] (3) Select the self-compatible BC1F1 generation plants as the female parent, remove the emasculation of the inflorescences of the female parent branches, and backcross with the self-incompatible winter rapeseed variety Longyou 7 as the recurrent parent to obtain the BC2F1 generation.
[0011] (4) Repeat step (3) to continue backcrossing until generation BC4F1 is obtained;
[0012] (5) Select individual plants with a compatibility index ≥6 and a relative compatibility index ≥60% from the BC4F1 generation plant population, bag them and self-pollinate them for a total of 3 generations to obtain the BC4F4 generation.
[0013] (6) Select plants from the BC4F4 generation with 100% self-compatible rate, compatibility index ≥6, relative compatibility index ≥60%, and uniform traits for isolation and propagation to obtain a strong winter-type Chinese cabbage-like winter rapeseed self-compatible line.
[0014] Preferably, the self-compatible BC1F1 generation plants in step (3) are self-compatible BC1F1 generation plants with a compatibility index ≥6 and a relative compatibility index ≥60%.
[0015] Preferably, the self-compatible BC1F1 generation plants also exhibit the characteristic of not bolting when sown in spring.
[0016] Preferably, the temperature for spring sowing is 10-25℃, and the growing period is 70-90 days.
[0017] Compared with the prior art, the present invention has the following beneficial effects:
[0018] This invention marks the first successful breeding of a high-compatibility self-pollination line for winter rapeseed of the Chinese cabbage type, named LRWCOM-12. LRWCOM-12 exhibits stable self-compatibility, with a 100% self-compatibility rate, a self-compatibility index ≥6, and a relative compatibility index ≥60%. It possesses excellent agronomic traits: plant height 130cm, branching point 40cm, 7 primary branches, 200 siliques per plant, ≥14 siliques per silique, silique length 5cm, beak length 0.5cm, 1000-seed weight 3.7g, and yield per plant 12g. It also features open petals, normal anther development, and 87% pollen viability; and good cold resistance.
[0019] This invention successfully bred a self-compatible, strong winter-growing Chinese cabbage-type winter rapeseed by crossing self-incompatible Brassica napus-type winter rapeseed with self-compatible Brassica napus-type winter rapeseed. This solves the problems of rapid degeneration and poor stability of winter-growing Chinese cabbage-type winter rapeseed varieties in northern China, providing germplasm and technology for the breeding of pure-line varieties of strong winter-growing Chinese cabbage-type winter rapeseed. At the same time, it resolves the contradiction between the need for parental homozygosity and self-pollination degradation in the utilization of heterosis in Chinese cabbage-type winter rapeseed, making it possible to increase the yield of strong winter-growing Chinese cabbage-type winter rapeseed in northern China by utilizing heterosis. Attached Figure Description
[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.
[0021] Figure 1 The characteristics of the inflorescence apex of the self-compatible line LRWCOM-12 selected in Example 1 are compared with those of the self-incompatible Chinese cabbage-type rapeseed Longyou 7. In the figure, the left is LRWCOM-12 and the right is Longyou 7.
[0022] Figure 2 The performance of the self-compatible line LRWCOM-12 selected in Example 1 in the field under cellophane bags for self-pollination and open pollination for pod formation;
[0023] Figure 3 The images show the fruit set of the self-incompatible line Longyou 7 and the self-compatible line LRWCOM-12 under open pollination and bagged self-pollination. The left image shows the fruit set of the self-incompatible line Longyou 7 under open pollination and bagged self-pollination, while the right image shows the fruit set of the self-compatible line LRWCOM-12 under open pollination and bagged self-pollination.
[0024] Figure 4 for Figure 3 Comparison of the pod formation of the self-incompatible line Longyou 7 and the self-compatible line LRWCOM-12 after bagging and removing the cellophane bag with open pollination;
[0025] Figure 5 A comparison of open-pollinated siliques (left) and self-pollinated siliques (right) of the self-compatible line LRWCOM-12;
[0026] Figure 6 Comparative results of stigma proteomics of the self-incompatible line Longyou 7 and the self-compatible line LRWCOM-12 of the winter-hardy Chinese rapeseed. Detailed Implementation
[0027] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.
[0028] Example 1
[0029] From autumn 2009 to spring 2010, in the experimental field of winter rapeseed in Shangchuan, Lanzhou, the self-compatible winter rapeseed variety Ganza 1 was used as the female parent and the self-incompatible winter rapeseed variety Longyou 7 (original code Mxw-1) was used as the male parent to obtain F1 generation seeds.
[0030] The F1 generation currently produces radish-shaped fruits with about 4 seeds per pod. It exhibits high self-incompatibility, and its offspring show deformities such as male infertility. It also shows significant variation and is not easily stabilized.
[0031] In the autumn of 2010, the F1 generation seeds obtained by hybridizing Ganza 1 and Longyou 7 were sown with Longyou 7 seeds in Shangchuan, Lanzhou. After the plants turned green and flowered in the spring of 2011, backcrossing was carried out using the F1 generation plants as the female parent and Longyou 7 as the recurrent parent (male parent) to obtain BC1F1 generation seeds.
[0032] In the autumn of 2011, BC1F1 seeds and Longyou No. 7 seeds were sown in Shangchuan, Lanzhou. In the spring of 2012, BC1F1 plants in the flowering period were bagged and self-pollinated, with 3 inflorescences bagged per plant and 10-12 flower buds bagged per inflorescence. Self-pollination was examined 10 days later. BC1F1 plants with high self-compatibility (compatibility index ≥ 6, relative compatibility index ≥ 60%) were selected as female parents and backcrossed with the recurrent parent (Longyou No. 7) to obtain BC2F2 generation seeds.
[0033] Self-compatibility index = Total number of siliques from bagged self-pollination / Total number of pollinated flowers;
[0034] Relative self-compatibility index = Average number of siliques per bagged self-pollinating silique / Average number of siliques per open-pollinated silique × 100%.
[0035] From autumn 2012 to spring 2014, following the work steps from autumn 2011 to spring 2012, self-compatible single plants with strong self-compatibility (self-compatibility index ≥ 6, relative compatibility index ≥ 60%) and plant type similar to cabbage were selected and backcrossed with the recurrent parents until BC4F1 generation seeds were obtained.
[0036] In the autumn of 2014, BC4F1 generation seeds were sown; after flowering the following spring, the BC4F1 generation plants were bagged and self-pollinated during the flowering period to detect changes in self-compatibility; individual plants with a compatibility index ≥6 and a relative compatibility index ≥60% were selected, and the selected self-compatible individual plants were tested at maturity, and the self-compatibility index was calculated. Individual plants with a compatibility index ≥6 and a relative compatibility index ≥60% were selected to obtain BC4F2 seeds;
[0037] Due to the segregation of self-compatibility and temperature sensitivity characteristics in the BC4F2 generation, BC4F2 seeds were sown individually at the Lanzhou Shangchuan base in the spring of 2016. (The main purpose of spring sowing was to eliminate plants with weak temperature sensitivity, as semi-wintering plants with weak temperature sensitivity can generally undergo vernalization, bolting, flowering, and eventually pod formation and maturity under spring sowing conditions or higher growing temperatures, while strong wintering plants can remain in a vegetative growth state, only growing leaves and not bolting.) After 70-90 days of growth following emergence, bolting plants were removed and eliminated, allowing the non-bolting plants that maintained a creeping growth pattern to continue growing. When the temperature dropped to around -10℃ in winter, the plants were covered with mulch to prevent damage from vegetative growth. Excessive exposure to prolonged conditions and excessively large vegetative bodies led to frost damage and death. In the spring of 2017, after flowering, BC4F2 generation plants were bagged and self-pollinated during the flowering period to assess changes in self-compatibility. Individual plants with a compatibility index ≥6 and a relative compatibility index ≥60% were selected. These selected self-compatible plants (those with an average of more than one silique in bagged self-pollination were considered self-compatible) underwent seed testing at maturity, and the self-compatibility index was calculated. The percentage of self-compatible plants was statistically analyzed, and individual plants with a compatibility index ≥6 and a relative compatibility index ≥60% were selected for threshing to obtain BC4F3 seeds. BC4F3 seeds were sown in the autumn of 2017. In the spring of 2018, self-pollination was continued during the flowering period, and individual plants with a compatibility index ≥6 and a relative compatibility index ≥60% were selected. BC4F4 generation seeds were obtained in June 2018.
[0038] Self-compatible plant rate = (Number of self-compatible plants in the population / Total number of plants in the population) × 100%.
[0039] In the autumn of 2018, the Lanzhou Shangchuan base was divided into 35 sub-areas, each with an area of 20 square meters. 2 BC4F4 generation seeds were sown manually in furrows, with 500 plants sown in each plot. In the spring of 2019, during the flowering period, self-pollination was carried out by bagging 100 plants per plot, with each plant bagged with 40 flower buds (4 inflorescences, 10 flower buds per inflorescence). Simultaneously, a 150-mesh nylon mesh was placed over each plot for isolation. After plant maturity, the self-compatibility rate (%), self-compatibility index, and relative self-compatibility index were calculated.
[0040] A self-compatible line with a self-compatibility rate of 100%, a self-compatibility index ≥6, and a relative self-compatibility index >60% was selected and named LRWCOM-12. After 2019, the morphological characteristics and stigma proteomics of the autumn-sown self-compatible line LRWCOM-12 were recorded and analyzed at various stages. The results are as follows: Figure 1-6 As shown.
[0041] Figure 1This study compares the characteristics of the inflorescence apex of the self-compatible line LRWCOM-12 and the Chinese rapeseed variety Longyou 7. The left image shows LRWCOM-12, and the right image shows Longyou 7. It can be seen that the inflorescence apex of LRWCOM-12 consists of unopened buds, with the open flowers located below them, while the unopened buds of Longyou 7 are covered by already opened flowers.
[0042] Figure 2 The results showed that the siliques of the self-compatible line LRWCOM-12 were developed normally in the field by self-pollination with cellophane bags and open pollination, and the length of the siliques was similar to that of the open-pollinated siliques.
[0043] Figure 3 The figures show the seed set of the self-incompatible line Longyou 7 and the self-compatible line LRWCOM-12 after open pollination and bagged self-pollination. The left figure shows the seed set of the self-incompatible line Longyou 7 after open pollination and bagged self-pollination, while the right figure shows the seed set of the self-compatible line LRWCOM-12 after open pollination and bagged self-pollination. The comparison shows that the self-incompatible line produces very few seeds, while the number of seeds produced by the self-compatible line is close to that of the open-pollination line, indicating that the high compatibility of the self-compatible line LRWCOM-12 is indeed true.
[0044] Figure 4 for Figure 3 A comparison was made between the pod formation of the self-incompatible line Longyou 7 and the self-compatible line LRWCOM-12 after removing the cellophane bags during bagged self-pollination and open pollination. The self-incompatible line produced very few pods after bagged self-pollination, which was significantly different from the number of pods produced by open pollination. In contrast, the number of pods produced by bagged self-pollination of the self-compatible line was close to the number of pods produced by open pollination, indicating that the self-compatible line LRWCOM-12 has high compatibility.
[0045] Figure 5 A comparison of open-pollinated siliques (left) and self-pollinated siliques (right) of the self-compatible line LRWCOM-12 was shown; it was found that the number of siliques produced by bagged self-pollination of the self-compatible line was close to the number of siliques produced by open pollination.
[0046] Figure 6 Comparative results of stigma proteomics of the self-incompatible line Longyou 7 and the self-compatible line LRWCOM-12 of the winter-hardy Chinese rapeseed.
[0047] In the autumn of 2020, 12 groups of the self-compatible line LRWCOM-12 were sown. In June 2021, the self-compatibility index, cross-compatibility index (i.e., the number of fruits per pod under open pollination conditions) and relative compatibility index were counted. The results are shown in Table 1.
[0048] Table 1. LRWCOM-12 self-compatibility index statistics for the 2021 harvest season (mid-June).
[0049] serial number Self-compatibility index Cross-fertility index Relative affinity index % LRWCOM-12-1 8.56 11.22 76 LRWCOM-12-2 15.33 16.22 95 LRWCOM-12-3 7.37 12.10 61 LRWCOM-12-4 6.78 9.22 74 LRWCOM-12-5 7.12 8.59 83 LRWCOM-12-6 6.47 9.4 69 LRWCOM-12-7 8.06 13.06 62 LRWCOM-12-8 9.08 15.24 60 LRWCOM-12-9 7.37 12.10 61 LRWCOM-12-10 9.47 12.80 74 LRWCOM-12-11 6.57 7.93 83 LRWCOM-12-12 7.80 10.27 76 average 8.33 11.51 73
[0050] As shown in Table 1, the self-compatibility index of individual plants in the LRWCOM-12 population after bagging is greater than 6.47, and the relative compatibility index is above 60%.
[0051] In the autumn of 2021, the self-compatible line LRWCOM-12 was sown again, totaling 11 groups. One group of Longyou 7 was also sown simultaneously as a control. Each group underwent both bagged self-pollination and open pollination treatments. Seed count, compatibility index, and relative compatibility index were recorded. The results are shown in Table 2.
[0052] Table 2. Results of LRWCOM-12 affinity index determination during the 2022 harvest season (mid-June).
[0053]
[0054]
[0055] As shown in Table 2, the self-compatibility index of bagged individual plants in the LRWCOM-12 population is greater than 6.47, and the relative compatibility index is above 60%.
[0056] As can be seen from the above embodiments, the present invention provides a method for breeding a strong winter-growing Chinese cabbage-type winter rapeseed self-compatible line, and successfully bred the strong winter-growing Chinese cabbage-type winter rapeseed high self-compatibility line LRWCOM-12. LRWCOM-12 has stable self-compatibility, with a self-compatibility rate of 100%, a self-compatibility index ≥6, and a relative compatibility index ≥60%.
[0057] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.
Claims
1. A method for breeding a strong winter-growing Chinese cabbage-type self-compatible line of winter rapeseed, characterized in that, Includes the following steps: (1) Using the self-compatible winter rapeseed variety Ganza 1 as the female parent and the strong winter rapeseed variety Longyou 7 as the male parent, hybridization was carried out to obtain the F1 generation; (2) Using F1 generation plants as the female parent and Longyou 7, a self-incompatible variety of winter rapeseed with strong winter-growing Chinese cabbage type, as the recurrent parent, backcrossing was carried out to obtain BC1F1 generation. (3) Select the self-compatible BC1F1 generation plants as the female parent, remove the emasculation of the inflorescences of the female parent branches, and backcross with the self-incompatible winter rapeseed variety Longyou 7 as the recurrent parent to obtain the BC2F1 generation. (4) Repeat step (3) to continue backcrossing until generation BC4F1 is obtained; (5) Select individual plants with a compatibility index ≥6 and a relative compatibility index ≥60% from the BC4F1 generation plant population, bag them and self-pollinate them for a total of 3 generations to obtain the BC4F4 generation. (6) Select plants from the BC4F4 generation with 100% self-compatible plant rate, compatibility index ≥6, relative compatibility index ≥60%, and uniform traits for isolation and propagation to obtain a strong winter-type Chinese cabbage-like winter rapeseed self-compatible line; The self-compatible BC1F1 generation plants mentioned in step (3) are BC1F1 generation plants with a self-compatibility index ≥6 and a relative compatibility index ≥60%. The self-compatible BC1F1 generation plants also exhibit the characteristic of not bolting when sown in spring. The ideal temperature for spring sowing is 10-25℃, and the growing period is 70-90 days.