Breeding method of new pitaya sterile line variety

Abstract

The application discloses a kind of pitaya sterile line new variety breeding method, belong to plant breeding technical field.The application method includes the following steps: using the pollen of complex ploidy pitaya to pollinate target female parent hybridization, harvest fruit;Seed is sowed seedling raising, and seedling is obtained;The chromosome ploidy of cotyledon of seedling is measured, and 3-ploid, 5-ploid, 3n+x, 4n+x, 5n+x pitaya offspring are screened;The seedling of screening is strong after grafting in mature old stock, and pollen death is obtained when group blooms, that is, pitaya male sterile line.The method is hybridized by selecting the pollen of complex ploidy pitaya, and through specific hybridization screening and the like, pitaya male sterile line is bred, and further through pollen compatibility, new line with excellent traits is obtained.The breeding method can effectively shorten breeding period, improve breeding efficiency, and the new variety of pitaya bred has characteristic color and taste, and fruit sweetness is high.

Description

Technical Field

[0001] The present invention relates to the technical field of plant breeding, and in particular to a method for breeding new varieties of pitaya sterile lines. Background Art

[0002] Pitaya, also known as red dragon fruit, dragon fruit, etc., is a species of the genus Hylocereus in the Cactaceae family ( Hylocereus ) or the genus Snakehead ( Seleniereus The dragon fruit plant, known for its sweet, nutritious, and health-promoting fruits, is widely popular worldwide and enjoys high market demand. With the continuous development of the dragon fruit industry, the requirements for dragon fruit varieties are also becoming increasingly higher. Cultivating high-quality new dragon fruit varieties has become a key to the industry's development.

[0003] Currently, pitaya breeding is primarily based on conventional hybridization. Conventional hybridization requires multiple generations of hybridization, selfing, and screening, typically requiring a significant period of time to produce new varieties with stable traits. Male sterile pitaya lines are crucial in hybridization, simplifying the hybrid seed production process, shortening the production cycle, and reducing production costs. However, the frequency of male sterile pitaya plants is extremely low under natural conditions, making screening them using conventional methods extremely difficult. Previous studies have observed and screened large numbers of pitaya plants, often only finding a very small number of male sterile plants. These sterile plants may not possess desirable traits and cannot be directly used for breeding new varieties. Currently, there are no reports on the successful cultivation and application of male sterile pitaya. Therefore, developing a method for breeding new pitaya varieties with male sterile lines is crucial for promoting the development of the pitaya industry. Summary of the Invention

[0004] Based on the deficiencies of the existing technology, the present invention aims to provide a method for breeding new pitaya sterile lines to solve the problem of difficulty in breeding existing pitaya male sterile lines, thereby quickly and efficiently breeding new pitaya varieties with excellent traits.

[0005] The technical solution of the present invention mainly includes the following contents:

[0006] A method for breeding new varieties of pitaya sterile lines comprises the following steps:

[0007] (1) Using pitaya pollen with complex ploidy to pollinate the target female parent and harvest the fruit;

[0008] (2) sowing the seeds and raising seedlings to obtain dragon fruit seedlings with changed fertility;

[0009] (3) Measure the chromosome ploidy of the cotyledons of pitaya seedlings, and screen out pitaya offspring with triploid, pentaploid, 3n+x, 4n+x, and 5n+x; "n" represents a chromosome set, which contains a complete set of non-homologous chromosomes necessary for the growth, development, and inheritance of the species. "3n", "4n", and "5n" represent triploid, tetraploid, and pentaploid respectively, that is, there are 3, 4, and 5 chromosome sets in the somatic cells respectively. "x" represents the additional number of chromosomes, x ≠ 0 and x < n; taking "3n + x" as an example, the total number of chromosomes in the cells of this pitaya is increased by x chromosomes based on the triploid (3n), and its chromosome composition is not a standard integer multiple, but a non-integer variation in chromosome number.

[0010] (4) After strengthening the selected polyploid seedlings, graft them onto mature old rootstocks to promote the rapid maturation of the branches and achieve high-quality growth of the scions; when the population is in bloom, detect the pollen viability and pollen amount, and obtain the plant lines with pollen death, that is, the male sterile lines of pitaya.

[0011] Further, in step (2), after disinfecting the seeds, inoculate them on the MS solid medium to promote seed germination. After the growth of the seedling is completed, transplant it to the seedling nursery for cultivation to obtain pitaya seedlings.

[0012] Further, pollinate the male sterile line of pitaya with the pollen of diploid pitaya to promote it to bear fruit, and obtain a pitaya strain with high yield, high sweetness, characteristic color and taste. Preferably, the pitaya strain can be self-crossed for multiple generations to stabilize the traits of the plants and obtain pure homozygotes, providing high-quality pure parental lines for further cross-breeding.

[0013] Further, the target female parents include diploid, diploid pitaya, etc.

[0014] Further, the diploid pitaya includes "Dahong" pitaya and "Wucihong" pitaya.

[0015] Further, the target female parents include pitaya varieties such as "Dahong" pitaya, "Wucihong" pitaya, "Meilong" pitaya, "Guilonghong" pitaya, and Brazilian red-skinned pitaya.

[0016] Further, the pollen of pitaya with complex ploidy shows a complex polyploid system, and the pollen ploidy simultaneously shows multiple ploidies such as haploid, diploid, and tetraploid.

[0017] Furthermore, the complex ploidy pitaya includes the "Bird's Nest" dragon fruit. "Bird's Nest" is a tetraploid plant produced by the hybridization of the genera of Hylocereus and Hylocereus, combining some characteristics of both genera. The more common "Bird's Nest" has yellow skin and white flesh. The aforementioned Brazilian red-skinned bird's nest fruit is a pitaya variety originating from Brazil, marketed as "Brazilian red-skinned bird's nest fruit," which has red skin and white flesh.

[0018] Furthermore, the pitaya with complex ploidy also includes other pitaya varieties such as "Black Dragon" pitaya, "Thornless Red" pitaya.

[0019] Furthermore, the rootstocks include "Jindu" pitaya, "Dahong" pitaya, etc.

[0020] Beneficial effects of the present invention:

[0021] The present invention can accurately screen out male sterile lines of pitaya, solves the problem of difficulty in screening male sterile lines in traditional methods, and provides effective materials for utilizing hybrid advantages of pitaya.

[0022] By rationally selecting parents, using pitaya pollen with complex ploidy to pollinate the target female parent for hybridization, and conducting rational screening and evaluation during the breeding process, the present invention can breed new pitaya sterile lines with excellent comprehensive traits. Pollination of male sterile plants can produce new pitaya lines with high sweetness, high yield, and distinctive color and taste. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 : Polyploid seedlings are grafted onto mature old rootstocks.

[0024] Figure 2 : Pollen viability detected by TTC staining. Left: Viable pollen. Right: Dead pollen, inactive pollen, and a large number of empty pollen shells.

[0025] Figure 3 : Select strains with dead pollen and pollinate pollen with diploid chromosome ploidy.

[0026] Figure 4 Seedlings derived from the hybridization of "Bird's Nest Fruit" and "Thornless Red" dragon fruits. The horizontal axis (PB450 - A) represents fluorescence intensity, which measures intracellular DNA content. A larger horizontal axis value indicates a higher cellular DNA content. The vertical axis (Count) represents the number of cells, i.e., the number of cells with a corresponding fluorescence intensity (DNA content).

[0027] Figure 5 : Results of chromosome ploidy detection of cotyledons of pitaya seedlings.

[0028] Figure 6: Fruits obtained after pollination of sterile line F2-88. DETAILED DESCRIPTION

[0029] In order to better understand the technical content of the present invention, the present invention is further described below in conjunction with specific embodiments and drawings.

[0030] Example 1

[0031] (1) Use the pollen of the more complex "Bird's Nest Fruit" to pollinate the target female parent ("Big Red" Pitaya) and harvest the fruit.

[0032] There are a large number of seeds with incomplete embryo development in the fruit, mainly red seeds: seeds with incomplete embryo development, black seeds: seeds with complete embryo, and white seeds: no seed coat and incomplete embryo development.

[0033] (2) After the seeds are disinfected, they are inoculated on MS solid culture medium to promote seed germination. After the seedlings have grown, they are transplanted to the nursery room for cultivation to obtain dragon fruit seedlings.

[0034] (3) The chromosome ploidy of the cotyledons of pitaya seedlings was measured by flow cytometry, and triploid, pentaploid, 3n+x, 4n+x, and 5n+x pitaya offspring were screened out.

[0035] (4) After the selected polyploid seedlings are strengthened, they are grafted onto the mature old rootstock of "Jindu" dragon fruit ( Figure 1 ), promote rapid aging of branches and achieve high-quality growth of scions. When the group blooms, the pollen activity and pollen quantity are detected by TTC staining, and it is found that the pollen quality of different strains is different ( Figure 2 ), pollen activity 0%-98%. Select the strains with dead pollen and pollinate with the pollen of diploid pitaya "Dahong" ( Figure 3 ), to promote its results.

[0036] (5) After fruiting, the quality of the fruits of each strain was measured, and strains with a central sweetness greater than 22% Brix and a yield of more than 8,000 jin / mu were obtained.

[0037] Example 2

[0038] (1) Use the pollen of “Bird’s Nest Fruit” with more complex ploidy to pollinate “Thornless Red” dragon fruit and harvest the fruit.

[0039] There are a large number of seeds with incomplete embryo development in the fruit, mainly red seeds: seeds with incomplete embryo development, black seeds: seeds with complete embryo, and white seeds: no seed coat and incomplete embryo development.

[0040] (2) After the seeds are disinfected, they are inoculated on MS solid culture medium to promote seed germination. After the seedlings have grown, they are transplanted to the nursery room for cultivation, and about 3,000 dragon fruit seedlings are obtained ( Figure 4 );

[0041] (3) The chromosome ploidy of the cotyledons of pitaya seedlings was measured by flow cytometry, and triploid, pentaploid, 3n+x, 4n+x, and 5n+x pitaya offspring were screened out. Figure 5 The results of chromosome ploidy detection of some cotyledons of pitaya seedlings are shown.

[0042] (4) The selected offspring seedlings were grafted onto sufficiently mature "Jindu" dragon fruit rootstocks to promote rapid aging of the seedlings and achieve high-quality growth of the scion. When the group bloomed, the pollen activity and pollen quantity were detected using the TTC staining method. The lines with dead pollen were selected and pollinated with pollen from the diploid dragon fruit "Wuxihong" to promote fruiting.

[0043] (5) After fruiting, the quality of the fruits of each strain was measured, and strains with a central sweetness greater than 22% Brix and a yield of more than 8,000 jin / mu were obtained.

[0044] Example 3

[0045] (1) Use the pollen of the more complex "Bird's Nest Fruit" to pollinate the target female parent ("Big Red" Pitaya) and harvest the fruit.

[0046] There are a large number of seeds with incomplete embryo development in the fruit, mainly red seeds: seeds with incomplete embryo development, black seeds: seeds with complete embryo, and white seeds: no seed coat and incomplete embryo development.

[0047] (2) After the seeds are disinfected, they are inoculated on MS solid culture medium to promote seed germination. After the seedlings have grown, they are transplanted to the nursery room for cultivation to obtain dragon fruit seedlings.

[0048] (3) The chromosome ploidy of the cotyledons of pitaya seedlings was measured by flow cytometry, and triploid, pentaploid, 3n+x, 4n+x, and 5n+x pitaya offspring were screened out.

[0049] (4) After the selected polyploid seedlings are strengthened, they are grafted onto mature rootstocks of the "Dahong" pitaya to promote rapid aging of the branches. When the group blooms, the pollen activity and pollen quantity are detected using the TTC staining method. The lines with dead pollen are selected and pollinated with pollen from the diploid pitaya "Wushihong" to promote fruiting.

[0050] (5) After fruiting, the quality of the fruits of each strain was measured, and strains with a central sweetness greater than 22% Brix and a yield of more than 8,000 jin / mu were obtained.

[0051] Example 4

[0052] (1) Use the pollen of the more complex "Black Dragon" pitaya to pollinate the target female parent ("Meilong No. 1" pitaya) and harvest the fruit.

[0053] There are a large number of seeds with incomplete embryo development in the fruit, mainly red seeds: seeds with incomplete embryo development, black seeds: seeds with complete embryo, and white seeds: no seed coat and incomplete embryo development.

[0054] (2) After the seeds are disinfected, they are inoculated on MS solid culture medium to promote seed germination. After the seedlings have grown, they are transplanted to the nursery room for cultivation to obtain dragon fruit seedlings.

[0055] (3) The chromosome ploidy of the cotyledons of pitaya seedlings was measured by flow cytometry, and triploid, pentaploid, 3n+x, 4n+x, and 5n+x pitaya offspring were screened out.

[0056] (4) After the selected polyploid seedlings are strengthened, they are grafted onto mature rootstocks of the "Dahong" pitaya to promote rapid aging of the branches. When the group blooms, the pollen activity and pollen quantity are detected using the TTC staining method. The lines with dead pollen are selected and pollinated with pollen from the diploid pitaya "Wushihong" to promote fruiting.

[0057] (5) After fruiting, the quality of the fruits of each strain was measured, and the strain with a central sweetness greater than 22% Brix, a distinctive color and taste, and a yield of more than 8,300 jin / mu was obtained.

[0058] Example 5

[0059] (1) Use the pollen of the more complex “thornless red” pitaya to pollinate the target female parent (Brazilian red-skinned bird’s nest fruit) and harvest the fruit.

[0060] There are a large number of seeds with incomplete embryo development in the fruit, mainly red seeds: seeds with incomplete embryo development, black seeds: seeds with complete embryo, and white seeds: no seed coat and incomplete embryo development.

[0061] (2) After the seeds are disinfected, they are inoculated on MS solid culture medium to promote seed germination. After the seedlings have grown, they are transplanted to the nursery room for cultivation to obtain dragon fruit seedlings.

[0062] (3) The chromosome ploidy of the cotyledons of pitaya seedlings was measured by flow cytometry, and triploid, pentaploid, 3n+x, 4n+x, and 5n+x pitaya offspring were screened out.

[0063] (4) After the selected polyploid seedlings are strong, they are grafted onto mature old rootstocks of "Dahong" pitaya to promote rapid aging of branches. When the group blooms, the pollen activity and pollen quantity are detected by TTC staining. The lines with dead pollen are selected and pollinated with pollen from diploid pitaya "Wuxihong" to promote fruiting ( Figure 6 ).

[0064] (5) After fruiting, the quality of the fruits of each strain was measured, and the strains of dragon fruit with a center sweetness greater than 22% Brix, a distinctive color (orange-red with a little light brown) and a taste (pomegranate flavor) were obtained, and the yield reached more than 8,000 jin / mu.

[0065] Comparative Example 1

[0066] Pollination with the "bird's nest fruit" pitaya as the male and female parents can produce fruit, but cannot obtain a sterile line, and cannot obtain a new strain of pitaya with distinctive color and taste.

[0067] Comparative Example 2

[0068] Pollination with "Dahong" pitaya as the male and female parents can produce fruit, but cannot obtain sterile lines and new pitaya lines with distinctive color and taste.

[0069] Comparative Example 3

[0070] Hybridization using "Jindu" pitaya as the male parent and "Dahong" pitaya as the female parent can produce fruit, but cannot obtain a sterile line, and cannot obtain a new pitaya plant line with distinctive color and taste.

[0071] The above descriptions are only some embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made by those skilled in the art within the spirit and principles of the present invention shall fall within the scope of protection of the present invention.

Claims

1. A method for breeding new varieties of pitaya sterile lines, characterized in that: The following steps are involved: (1) Using pitaya pollen with complex ploidy to pollinate the target female parent and harvest the fruit; The pitaya pollen with complex ploidy exhibits a complex polyploid system, and the pollen ploidy exhibits both haploid and diploid characteristics; the pitaya with complex ploidy is a "bird's nest fruit" pitaya, a "black dragon" pitaya, or a "thornless red" pitaya; The target female parent is "Dahong" pitaya, "Spineless Red" pitaya, "Meilong" pitaya, "Guihonglong" pitaya or Brazilian red-skinned bird's nest fruit; Among them, the female parent pollinated by the pollen of "Bird's Nest Fruit" dragon fruit is "Big Red" dragon fruit or "Thornless Red" dragon fruit; the female parent pollinated by the pollen of "Black Dragon" dragon fruit is "Mei Long" dragon fruit; the female parent pollinated by the pollen of "Thornless Red" dragon fruit is Brazilian Red-skin Bird's Nest Fruit; (2) sowing the seeds and raising seedlings to obtain dragon fruit seedlings with changed fertility; (3) Measure the chromosome ploidy of the cotyledons of pitaya seedlings and select triploid, pentaploid, 3n+x, 4n+x, or 5n+x pitaya offspring; "n" represents a chromosome set, "x" represents the number of additional chromosomes, x ≠ 0 and x < n; (4) The selected polyploid seedlings are grafted onto mature old rootstocks after they have grown strong. When the population blooms, the pollen activity is tested to obtain the lines with dead pollen, i.e., the male sterile lines of pitaya. The rootstock is "Jindu" dragon fruit or "Dahong" dragon fruit.

2. The method for breeding new varieties of pitaya sterile lines according to claim 1, wherein The male sterile pitaya line was pollinated with diploid pitaya pollen to induce fruiting.

3. The method for breeding new varieties of pitaya sterile lines according to claim 2, wherein The diploid pitaya is a "big red" pitaya or a "thornless red" pitaya.

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