A method of breeding a distantly related cross of a purple mustard line

Abstract

The present application belongs to the technical field of biological breeding, and provides a distant cross breeding method of a purple mustard line. The present application prepares a new type of purple mustard line through distant cross, introduces the purple trait of Brassica napus into Guangning large mustard, and cultivates a purple leaf and stem type large mustard, thereby obtaining an excellent strain with deep purple leaves, and making up for the shortage of purple mustard variety resources on the market.

Description

Technical Field

[0001] This invention belongs to the field of biological breeding technology and relates to the preparation of purple mustard varieties, specifically to a method for distant hybridization breeding of purple mustard varieties. Background Technology

[0002] Distant hybridization refers to the technique of crossing different species, genera, and even more distantly related species in plant taxonomy. It is an important pathway to achieve gene exchange between species and create new germplasm. It can also be used to study the theory of genetic recombination between subgenomes through the artificial synthesis of polyploids from multiple species. However, due to severe reproductive isolation between species, distant hybridization often faces technical bottlenecks such as hybridization incompatibility, embryo abortion, and rampant segregation in offspring. In most crops, distant hybridization still faces challenges such as low success rates and difficulties in directional selection, urgently requiring the development of more successful breeding practices. In the field of rapeseed breeding, distant hybridization has successfully created a number of groundbreaking new varieties. The most typical example is the use of somatic cell hybridization between rapeseed and Isatis indigotica (woad), which, after years of selection, resulted in the "Isatis indigotica Green Vegetable" ("Songyou No. 1"). This variety not only retains the edible quality of rapeseed flower stalks but also incorporates the antiviral components and high calcium and zinc properties of Isatis indigotica. It has been widely adopted in Hubei, Gansu, Yunnan, and other regions, becoming a benchmark achievement for functional vegetables. Furthermore, through distant hybridization between rapeseed and closely related species such as Orychophragmus violaceus and radish, intermediate breeding materials with excellent traits have been obtained, further demonstrating the unique value of distant hybridization in broadening the genetic base of rapeseed.

[0003] Purple-leaf mustard-type rapeseed (Brassica juncea) is an important dual-purpose crop for both oilseed and vegetable production within the Brassicaceae family. Its purple leaves, primarily due to anthocyanin accumulation, not only offer excellent ornamental value but also endow the plant with strong stress resistance and antioxidant properties, making it a promising candidate for development as a vegetable, a tourist attraction, and a health food product. However, the germplasm resources of purple-leaf mustard-type rapeseed are currently relatively scarce. Existing purple materials exhibit unstable leaf color expression and suffer from low yield and poor disease resistance, making direct application in production difficult. Traditional breeding methods are limited by the narrow genetic diversity within mustard-type rapeseed, making it challenging to simultaneously improve leaf color while combining high yield, high quality, and disease resistance through conventional hybridization.

[0004] Creating novel purple mustard varieties using distant hybridization technology has significant advantages: First, it can overcome interspecific reproductive barriers, introducing key genes regulating anthocyanin synthesis and high stress resistance genes from other cruciferous species (such as woad, violet, radish, and Chinese cabbage-type rapeseed) into mustard-type rapeseed, achieving targeted improvement of the purple trait and synergistic aggregation of multiple traits. Second, the offspring produced by distant hybridization typically exhibit rich trait segregation, providing a broad selection space for breeding new varieties with comprehensive superior traits such as purple color, high quality, high yield, and disease resistance. Third, drawing on the successful model of "Isatis root mustard," purple-leaf mustard-type rapeseed created through distant hybridization can not only be promoted as a specialty flowering scape variety but also expanded into functional food development and agritourism, demonstrating significant economic benefits and market prospects. Therefore, conducting research on the creation of purple-leaf mustard-type rapeseed through distant hybridization is of great significance for enriching rapeseed germplasm resources and increasing the added value of the rapeseed industry. Therefore, this invention provides a method for distant hybridization breeding of purple mustard varieties, solving the above-mentioned technical problems. Summary of the Invention

[0005] The purpose of this invention is to provide a distant hybridization breeding method for purple mustard varieties, which involves distant hybridization of Guangning large mustard and Brassica napus purple rapeseed, introducing the purple trait of closely related species into Guangning large mustard, thus providing a new approach and means for the development of new vegetable varieties.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows:

[0007] This invention provides a method for distant hybridization breeding of purple mustard varieties. The method specifically includes: selecting a Brassica napus with dark purple leaves as the male parent and Guangning mustard as the female parent; through distant hybridization, selecting plants with extremely dark purple and large leaves as the parent in the first generation; backcrossing Guangning mustard as the recurrent parent for two generations; and finally selecting plants with large and purple leaves for two generations of interbreeding and cultivation into the finished product.

[0008] Preferably, the specific cultivation conditions are as follows: sowing in a greenhouse, potted plants, temperature set between 23-25℃, humidity varying between 65-85% during light and dark periods, and photoperiod set to light / dark: 16 h / 8 h.

[0009] The present invention also provides a novel mustard-type purple rapeseed obtained according to the above-described distant hybridization breeding method.

[0010] Preferably, the novel mustard-type purple rapeseed has no fewer than 20 secondary branches and strong branching ability.

[0011] The beneficial effects of this invention are:

[0012] This technology created a new purple mustard variety through distant hybridization, introducing the purple trait of Brassica oleracea-type purple rapeseed into Guangning mustard greens to cultivate a purple leaf and stem type of mustard green. By employing a novel method for cultivating purple mustard greens and introducing the purple trait of closely related species, a superior strain with a deep purple leaf color was obtained, filling the current gap in the market for purple mustard greens. Attached Figure Description

[0013] Figure 1 These are the maternal and paternal plants in this invention (A is the maternal plant, Guangning mustard; B is the paternal plant, purple-leafed rapeseed).

[0014] Figure 2 This is a novel purple-leaf mustard-type rapeseed in this invention;

[0015] Figure 3 This is the implementation process of an application example in this invention. Detailed Implementation

[0016] Unless otherwise specified, the experimental methods used in the following examples are conventional methods.

[0017] Unless otherwise specified, all materials and reagents used in the following examples are commercially available.

[0018] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0019] Application examples

[0020] 1. Source of materials

[0021] Guangning Big Mustard Greens: This variety originates from Guangning County, Zhaoqing City, and is a mustard-type rapeseed. It has a large plant size, large, oval leaves with petioles and multiple pairs of lateral lobes. The leaves are hairless, and the stems and leaves are edible and slightly sweet, which meets the typical characteristics of mustard-type rapeseed.

[0022] Purple-leaf Brassica napus: This variety is derived from a Brassica napus strain with deep purple leaves, which was independently cultivated by the applicant and conforms to the typical characteristics of Brassica napus.

[0023] 2. Breeding pedigree

[0024] In March 2022, a distant hybridization was conducted using Guangning large mustard (2n=36, AABB) as the female parent and purple-leaf cabbage type rapeseed (2n=38, AACC) as the male parent. Figure 1In May 2022, F1 generation seeds were obtained. In March 2023, individuals with large purple leaves were selected from the F1 generation plants (2n=37, AABC). This plant was a distant hybrid with an odd number of chromosomes in its genome. During gamete production, chromosome pairing was disordered, resulting in very low pollen fertility. Using this plant as the female parent, it was further hybridized with Guangning mustard greens to produce backcross BC1 generation, and the hybrid was retained.

[0025] The seeds were sown in November 2023. In March 2024, purple-leaved and large-leaved plants were selected in the field and crossbred with Guangning mustard greens to produce backcross BC2F1 generation. The hybrids were retained and sown in November 2024. In March 2025, purple-leaved and large-leaved fertile lines were selected in the field and crossbred with these lines. The seeds produced in May 2025 were the BC2F2 generation self-crossed seeds.

[0026] In June 2025, the seeds were sown in flowerpots in a greenhouse, and a new type of purple-leaf mustard rapeseed was obtained in December 2025. Figure 2 The plant's genome has essentially returned to normal, making it a fertile line. The entire process is as follows: Figure 3 As shown.

[0027] 3. Cultivation conditions

[0028] The parent lines and intermediate breeding materials were all planted in the rapeseed experimental field of Zhaoqing University in Zhaoqing City, Guangdong Province. The specific steps are as follows:

[0029] (1) Selection of planting plots: Select plots with thick soil, fertile soil, sufficient sunlight, and moderate pH value.

[0030] (2) Land preparation before sowing: harrow the land appropriately to make the soil uniform, and apply compound fertilizer, trace elements and boron fertilizer mixed in a certain proportion as base fertilizer. Plant on raised beds with a bed width of about 120 cm, a plant spacing of 20 cm and a row spacing of 40 cm, with a density of 3000 to 3500 plants per mu.

[0031] (3) Field management: Remove weeds in time before the canopy closes in the early stage, focus on preventing and controlling the damage caused by flea beetles and cabbage caterpillars, remove weeds in time, ensure sufficient and balanced water and fertilizer supply, water frequently with small amounts, and avoid flooding. Spray foliar fertilizer during the seedling and flowering stages, and supplement boron, calcium and other trace elements in time to ensure the supply of micronutrients. Spray pesticides periodically to prevent the occurrence of diseases and pests.

[0032] (4) Pollination: Select superior male plants and bag them during the flowering period, and use artificial emasculation and pollination to pollinate the female plants.

[0033] A new type of mustard-type rapeseed developed in 2025:

[0034] Sow in a greenhouse, in pots, with the temperature set between 23-25℃, and the humidity varying between 65-85% during light and dark periods. The photoperiod is set to light / dark: 16 h / 8 h.

[0035] 4. Phenotypic characteristics of the novel purple-leaf mustard-type rapeseed:

[0036] Phenotypic average data: 8 primary effective branches; plant height 113 cm at full bloom; canopy height 97 cm. Leaves are elliptical with shallowly lobed margins and 2 pairs of lateral lobes; they are free of bristles and wax powder. The largest leaf on potted plants is 26 cm long and 13 cm wide. The petioles of the stem-leaf scapes are semi-amplexicaul, about 5 cm long. There are 25 secondary branches. It has strong branching ability, separate petals, and short, slender siliques with a sweet taste.

[0037] In summary, this invention has created a new purple mustard variety through distant hybridization, introducing the purple trait of Brassica oleracea-type purple rapeseed into Guangning large mustard, and cultivating a purple leaf and stem type of large mustard, thus making up for the current shortage of purple mustard varieties in the market.

[0038] The above-described embodiments are merely preferred embodiments of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the appended claims.

Claims

1. A method for distant hybridization breeding of a purple mustard variety, characterized in that, The method specifically includes: selecting a Brassica napus with dark purple leaves as the male parent and Guangning mustard as the female parent; through distant hybridization, selecting plants with extremely dark purple and large leaves as the parent in the first generation; backcrossing Guangning mustard as the recurrent parent for two generations; and finally selecting plants with large and purple leaves for two generations of interbreeding and cultivation into the finished product.

2. The method for distant hybridization breeding according to claim 1, characterized in that, The specific cultivation conditions are as follows: sowing in a greenhouse, potted plants, temperature set between 23-25℃, humidity varying between 65-85% during light and dark periods, and photoperiod set to light / dark: 16 h / 8 h.

3. A novel mustard-type purple rapeseed obtained by the distant hybridization breeding method according to any one of claims 1-2.

4. The novel mustard-type purple rapeseed according to claim 3, characterized in that, The novel mustard-type purple rapeseed has no fewer than 20 secondary branches and strong branching ability.

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