Method for breeding beet male parent pollination line by using beet combining ability recurrent selection

Abstract

The invention provides a method for breeding a beet male parent pollination line by utilizing beet combining ability recurrent selection, which comprises the following steps of: changing general matching selection of an inbred line into general combining ability identification of early-generation test cross so as to screen out an inbred line with high combining ability, and identifying and selecting a better new pollination material by utilizing special combining ability; adding external materials into other materials, mixing to form a comprehensive group, selecting seed plants, cultivating mother roots, and entering a next combining power recurrent selection procedure. According to the method, general combining ability identification is carried out in advance to early generation of strains, so that the selection range of materials is expanded; the strain material always keeps strong viability, and the character is not weakened; through preselection of general combining ability identification and special combining ability identification, it can be guaranteed that new male parent materials can be bred by 100%; old materials can be upgraded to create new male parent materials; the gene heterozygosis rate is increased, and the material character is improved; the next-generation material always keeps the character advantage, and the pollen amount is sufficient; the whole breeding method is higher in pertinence and directivity.

Description

Technical Field

[0001] The present application relates to the field of crop planting technology, and in particular to a method for breeding a sugar beet male parent pollination line by utilizing sugar beet combining ability recurrent selection. Background Art

[0002] Beet breeding is a complex undertaking, requiring both pairing and selecting the female parent and creating high-quality paternal material. The paternal material is typically obtained through continuous self-pollination of pollen-producing plants to create pure lines. Externally, these plants exhibit dwarfism, decreased vitality, and reduced stress resistance. These are the characteristics of self-pollinated lines. Once these lines are established, breeders pair them with sterile lines, sow them in the spring of the following year, and identify the optimal inbred line based on the results. This optimal inbred line then becomes the new pollination material. This process involves multiple generations of self-pollination of the inbred material, which is then paired with the sterile line to create new pollination material. The drawback is that while new pollination material is selected, the selection range is too narrow, resulting in limited new pollination material.

[0003] The existing technology is to select fertile plants and self-pollinate to form a line, then select individual plants and self-pollinate again, repeating this process until a line with a high fertility rate is selected, and then spatially isolate and propagate it. It is then combined with the sterile line, sown in spring, and identified to select a new pollination line.

[0004] The disadvantage is that fertile plants are self-pollinated multiple times to form strains. These strains are then combined, and the resulting strains are high-generation self-pollinated materials. During these multiple generations of self-pollination, many useful genes have been lost, making the strains too homozygous. When combined with sterile lines, the chances of producing high-value materials are slim, leading to the loss of high-combining-ability materials and a narrowing of the pipeline for obtaining new pollination materials. Consequently, fewer new materials are selected. Summary of the Invention

[0005] In response to the above-mentioned technical limitations, the present application proposes a method for breeding sugar beet male parent pollination lines using sugar beet combining ability recurrent selection; it overcomes the deficiencies and defects mentioned in the background technology.

[0006] This application introduces a pre-staged combining ability identification process, which is implemented during the initial phase of plant formation. This process allows for the selection of a large number of high-combining ability lines. This creates conditions for subsequent rounds of combining ability selection and also provides opportunities for breeding more pollination material. The remaining materials are mixed together, and then exogenous materials are added for seed selection, before entering the next round of combining ability selection. This not only selects highly combining pollination lines with high efficiency, but also allows for the addition of additional exogenous materials, if necessary, to enrich the overall population genotype, before entering the same selection process.

[0007] To achieve the above objectives, this application adopts the following technical solutions: The invention of this application is to provide a method for breeding sugar beet male parents, comprising the following steps: S1. In the first year, an original population A of 10 sugar beet varieties was selected and planted in a diseased field to select for disease resistance. S2. In the second year, the selected disease-resistant varieties are interplanted with their mother roots, crossbred with other fertile plants, and selected for seedlings to obtain fertile plants. S3 third year, in step S2 obtained in a fertile plant again in the selection of plants, small groups after cross-fertilization to obtain two fertile plants, fertile plants two cut flower bagging to form strain B; In the fourth year, strain B was cultured with three sterile lines, and seeds were harvested for general combining ability testing. S5. In the fifth year, spring sowing yield and quality assessment is conducted, and each line is self-pollinated to produce self-pollinated first-generation seeds; In the sixth year, the two parent roots selected after general combining ability assessment are mated with the optimal sterile line, followed by special combining ability assessment and selection. The remaining self-pollinated first generation are then planted together to form integrated population 1. S7. In the seventh year, the two parent roots from step S6 are combined with the optimal sterile line for spring sowing and harvested. The yield and quality of the seeds are evaluated using special combining ability, and the seeds from the optimal combination are selected. The male parent of the seeds from the optimal combination becomes the created pollination line. Simultaneously, the two parent roots from step S6 are self-pollinated to produce second-generation self-pollinated seeds, which are then planted with integrated population 1 to form integrated population 2. S8. In the eighth year, the integrated group 2 mother roots and hybrid varieties of foreign materials were mixed and planted to form an integrated group 3, and the selection of seed plants was performed; S9. In the ninth year, after the seed plants are selected, the strains are formed and the next round of selection is carried out.

[0008] Optionally, in the above-mentioned method for breeding the male parent of sugar beet, in the step S1, in early April of the first year, the original group A of 10 new sugar beet varieties is introduced and planted in a diseased garden, and the external performance of each sugar beet variety is observed before harvest, with the leaf cluster height being 40-75cm, the leaf area being 170-230cm2, and the leaf color and leaf area need to be observed for leaf wrinkles and leaf edge waves; the disease resistance needs to be observed for resistance to rhizomes, root rot, and brown spot; after the autumn harvest, the yield and sugar content are measured, and the sugar beet variety with the largest local production volume is used as the control, and sugar beet varieties with a yield and quality exceeding or equivalent to the control are selected; for the selected new sugar beet varieties, 100 single roots are selected for each variety, and the selection criteria are: the weight is selected to be between 900g and 1200g, the root body is smooth, the root shape is good, the root groove is shallow, and the root head is small, and all the mother roots are mixed and stored in a cellar.

[0009] Optionally, in the above-mentioned method for breeding the male parent of sugar beet, in step S2, in late March of the second year, the rotten mother roots are removed and the sugar content is checked again. At this time, the sugar content standard is ≥16%, and the mother roots that do not meet the standard are removed, and the mother roots that meet the standard are planted in a spatial isolation area with a plant spacing of 50 cm and a row spacing of 40 cm; during the flowering period, the plants freely pollinate each other, and the individual plants with sufficient pollen are observed and determined. The individual plants with sufficient pollen are marked and retained, and the rest are pulled out; between July 25 and August 5 of the same year, the individual plants retained for summer sowing are marked with a plant-row spacing of 10×50 cm, and each plant is sown separately in an area to cultivate the mother roots; from the end of October to the beginning of November, the mother roots with a weight greater than 100 g are harvested in autumn, and the rest are discarded. The mother roots are placed in a cellar and buried with washed sand with a moisture content of 60%, and the temperature in the cellar is 1-5°C and the humidity is 60%-80%.

[0010] Optionally, in the above-mentioned method for selecting the male parent of sugar beet, in step S3, the mother roots stored in step S2 are taken out in late March of the third year, and each mother root is planted in a separate space with an interval of 5000 meters between each mother root; during the flowering period, the individual plants with sufficient powder are observed again and marked, and the individual plants with sufficient powder are removed, and after the flowers are cut and bagged, they are sown with a spacing of 10×50 cm between July 25 and August 5 of the same year to cultivate the mother roots; at the same time, the yield of three summer sowings is ≥6 tons / 667m 2 , the mother roots of the sterile lines cms1, cms2, and cms3 seeds with a sugar content ≥16% were harvested and stored in cellars.

[0011] Optionally, in the above-mentioned method for breeding the male parent of sugar beet, in step S4, a general combining ability identification is carried out in the fourth year, that is, the mother root of each plant line in step S3 is planted together with the three sterile lines cms1, cms2, and cms3, and the distance between them is 5,000 meters. Seeds are harvested from each sterile line, and 3 seeds are harvested from 3 sterile lines. The 3 seeds are then identified for spring sowing, and the average value is calculated; 4 seeds are harvested in each isolation point, 3 test cross seeds are harvested from the three sterile lines, and one self-pollinated first-generation seed is harvested from the plant line.

[0012] Optionally, in the above-mentioned method for breeding the male parent of sugar beet, in step S5, in the fifth year, the seeds harvested from cms1, cms2, and cms3 are subjected to spring sowing identification, normal management, and harvested in autumn; then a yield and quality identification is performed, i.e., 10 sugar beets are randomly selected from the harvested materials for single-plant sugar measurement to obtain the average value; the sugar beets produced by each test cross seed are weighed, and converted into per mu yield based on the sowing area; the sugar content and per mu yield are the yield and quality of the test cross seed; based on the results, the mother root material of the plant line with an average yield and quality better than the control is selected, and its corresponding male parent is the selected material with development prospects.

[0013] Optionally, in the above-mentioned method for breeding the male parent of sugar beet, in the step S6, the two self-pollinated first-generation mother roots with the best performance in the general combining ability selection are selected in the sixth year, and are test-crossed with the optimal sterile line cms4 mother root cultivated in step S5, and the self-pollinated second-generation seeds and the test-cross seeds are harvested respectively, and the self-pollinated second-generation seeds are sown in the summer of the same year, and the self-pollinated second-generation mother roots are cultivated and stored in a cellar; the self-pollinated first-generation mother roots are concentratedly planted in the same year to synthesize the integrated group 1, and free open pollination is carried out within the group during the flowering period, and then seed plants are selected, and the dominant seed plants are selected, and the rest are eliminated. The seeds of the dominant seed plants are harvested in the same year, and the mother roots are sown in the summer of the same year, which are the mother roots of the integrated group 1.

[0014] Optionally, in the above-mentioned method for breeding the male parent of sugar beet, in the step S7, the combination of the test cross in step S6 is subjected to a special combining ability identification test in the seventh year, and the specific method is: the test cross seeds harvested are sown in spring, and the sugar content is measured and weighed after harvest in autumn, and the unit yield is calculated. After comparison with the control, the combination that exceeds the control is selected, and the optimal combination is determined by the yield, and the male parent of the optimal combination is the pollination material; at the same time, the mother roots of the integrated group 1 and the self-pollinated second-generation mother roots formed by the test cross are mixed together, and planted together to synthesize the integrated group 2; free open pollination is carried out in the group during the flowering period, and then seed plants are selected, and the dominant seed plants are selected, and the rest are eliminated. The seeds of the dominant seed plants are harvested in the same year, and the mother roots are sown and cultivated in the summer of the same year, which are the mother roots of the integrated group 2.

[0015] Optionally, in the above-mentioned method for breeding the male parent of sugar beet, in step S8, the integrated population 2 is mixed with the mother roots of another hybrid variety and planted in the eighth year to synthesize the integrated population 3.

[0016] The key technical points of the present invention are: We can select basic materials in a targeted and directional manner, or adopt new methods based on existing pollination materials to tap the potential of existing pollination materials and produce new pollination systems.

[0017] The original population is selected from better hybrids or materials commonly used in current production. Alternatively, selected pollination materials can be used as the original population.

[0018] Plant the original population together in an open environment and allow free pollination during the flowering period. Select individual plants with good plant shape and sufficient pollen for labeling. Alternatively, among the existing pollination materials, the pollination lines to be modified can be planted together and allowed to open pollinate. Harvest seeds from the individual listed plants, sow them that summer, and cultivate mother roots for storage in a cellar.

[0019] The following spring, remove the mother roots and plant them separately, 5,000 meters apart. Select the seedlings, cut the individual flowers, and label them. Mark them carefully. Sow again in the summer, cultivate the mother roots, and store them in a cellar. At the same time, plant the three high-yield varieties, CMS1, CMS2, and CMS3, in the summer, cultivate the mother roots, and store them in a cellar.

[0020] The following year, the mother root was removed and each line's mother root was planted together with the three CMS1, CMS2, and CMS3, and seeds were harvested separately. The following year, the seeds harvested from CMS1, CMS2, and CMS3 were identified for spring sowing.

[0021] The above steps are to identify the general compatibility of the strains. At this point, based on the results, a certain number of strains with poor yield quality are eliminated, and the strains with the greatest potential for development are screened out, thus avoiding the loss of good materials.

[0022] The superior materials selected through general combining ability assessment are then used to cultivate mother roots from their self-pollinated progeny and undergo special combining ability assessment. Based on the results, superior materials are again selected, and their tissue cultured male parent materials become the new pollination lines. The remaining materials continue to be sown in summer to cultivate mother roots, then planted together again, open pollinated, selected seed plants, listed, harvested, and cultivated mother roots.

[0023] Testcrossing is then performed again with a CMS4 (the best-performing sterile line used in production) to determine the specific combining abilities of these strains. Based on the results, the optimal combination is selected to determine the optimal male parent material. The remaining materials are then sown again in summer, small female roots are cultivated, and stored. The following year, they are mixed together, planted collectively, open-pollinated, selected, labeled, and the seeds harvested.

[0024] Following the above breeding process, after mixed harvesting and strain formation, general combining ability is assessed. This maximizes the selection of promising materials. Additionally, existing pollination materials are modified. If, during this process, the yield and quality of selected combinations decline, additional foreign materials can be promptly introduced for open pollination, enriching the material's genotypes and increasing the degree of genetic hybridization, thereby finding a solution to maintain trait attenuation.

[0025] Compared with the prior art, this application has the following advantages: 1. The general combining ability identification is advanced to the early generation of the strain, which expands the selection range of materials. The acquisition rate of high combining ability materials is increased by 30%. The original breeding method is to carry out bagging and self-pollination for each strain separately, and continue bagging and self-pollination for 4-5 generations until the fertility rate of the offspring of a certain strain reaches 75%. These 75% strain materials are then used for group matching. General combining ability and special combining ability identification are not performed. This method, however, conducts general combining ability identification when the strain is formed, and selects promising strain materials. This method was not included in the original breeding method. Since general combining ability identification is carried out during the strain formation period, the probability of selecting valuable materials is 100% higher than the original method.

[0026] 2. Due to the proper method of this application, the traits of each material will not weaken and the vitality will not decrease during the breeding process. The original breeding method is to carry out bagging and self-pollination after the strain is formed, and it takes 4-5 generations until the fertility rate of a certain strain reaches 75%, which leads to the vitality and traits of the offspring of the strain becoming weaker and weaker, with an overall decrease of 50%. However, the strains of this method are intercrossed, so the strain materials always maintain strong vitality and the traits are not weakened.

[0027] 3. This application uses early identification of general combining ability to prevent the loss of high-combining ability materials. Special combining ability identification is then performed promptly, allowing new pollination lines to be bred early. The fertility-rich materials bred using existing methods are obtained only after multiple generations of continuous self-pollination of the lines. This is actually a high-purity inbred line. This method, however, performs general combining ability identification at the time of bred, which is equivalent to a pre-selection of each line. Only qualified lines are then subjected to special combining ability identification, resulting in a 100% chance of bred new male parents. The original method, however, was blind and random.

[0028] 4. This method can be used to upgrade and transform old materials to create new materials. Since the materials selected by the old method are inbred lines, a new material can be introduced and interbred with it, and then individual plants can be selected. However, according to the method of this application, the probability of creating a new and better paternal material is 100%, which is also an upgrade and transformation of old materials, thereby creating new paternal materials.

[0029] 5. If, during the breeding process, the yield and quality of the strain material are found to have declined, foreign materials can be added before the special combining ability is determined to enrich the population genes and improve the quality of the population traits. Due to the increase in the gene heterozygosity rate, the traits of the material are greatly enhanced.

[0030] 6. By using concentrated planting between strains, mixed pollination, and then selecting the plants, the next generation of materials can always maintain the trait advantages and the pollen supply of the plants is sufficient. This method uses inter-strain crosses to achieve a high genetic heterozygosity rate in the strain materials, which is not achievable by self-pollination within the strain in the existing technical solutions. The advantages of this application method are obvious.

[0031] 7. This application method has clear objectives and strong control. Using two-stage testing and identification, it not only selects inbred lines with high combining ability, but also promptly selects new pollination lines. Because the general combining ability of each strain is assessed early in the breeding process, high-combining inbred lines are selected early. This method is more targeted and directional than previous breeding methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a conceptual diagram of the process of Example 1 of this application, wherein: Year 1: The original population (A1, A2, A3, A4....A10) is selected for disease resistance in the disease nursery; Second year: Select and retain disease-resistant varieties, interplant mother roots, intercross fertile plants, and make seed plant selection; In the third year, seed plants are selected again from the above fertile plants, and small groups are intercrossed. The fertile plants are cut and bagged to form strain B; Year 4: The strain was mated with three sterile lines, and seeds were harvested from the three sterile lines for general combining ability assessment. The fifth year: the spring sowing yield quality assessment is carried out, and at the same time, each plant line is self-pollinated to form the self-pollinated first-generation seeds; Year 6: After identification, the two best ones are selected to enter the next process (special combining ability selection), and the remaining self-pollinated first-generation materials are planted together to form comprehensive group 1; Year 7: The best material selected through general combining ability assessment is then paired with the best sterile line, CMS4, for specific combining ability assessment. Seeds harvested from spring sowing on CMS4 are assessed for yield and quality, and the best combination is selected, whose male parent is the latest pollination line. The other two materials paired with CMS4 are also self-pollinated to form second-generation self-pollinated seeds, which are then combined with comprehensive population 1 to form comprehensive population 2. Year 8: The mother roots of foreign materials are mixed with the mother roots of integrated group 2 and cross-pollinated during the flowering period to form integrated group 3, and seed plants are selected; Year 9: The plants are grown to form strains and the next round of selection is carried out.

[0033] Figure 2 This is a flowchart of the process of breeding pollination lines using the recurrent selection method for combining ability of sugar beets for this application. DETAILED DESCRIPTION

[0034] To make the purpose, technical solutions and advantages of this application more clear, this application is further described in detail below. However, it should be understood that the description herein is only used to explain this application and is not intended to limit the scope of this application.

[0035] Unless otherwise defined, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which this application pertains. The terms used herein in the specification of this application are intended solely for the purpose of describing specific embodiments and are not intended to limit this application. The reagents and instruments used herein are commercially available, and the characterization methods involved can be found in the relevant descriptions in the prior art and will not be further elaborated herein.

[0036] In order to further understand the present application, the present application is further described in detail below in conjunction with the best embodiment.

[0037] Example 1 Phenotypically, they should have low foliage, spindle-shaped or wedge-shaped tubers, short root tips, and smooth root surfaces. Hybrids with these characteristics can be used as seed stocks. These seed stocks are primarily resistant to sugar beet diseases, so varieties with these characteristics are selected for planting in diseased nurseries. After screening, disease-resistant seed stocks proceed to the next stage.

[0038] In the first year, 10 varieties are introduced and tested in disease-tolerant fields. Those that are not disease-resistant are eliminated. In autumn, the remaining varieties are tested for sugar content and weighed to verify their yield and quality. If two varieties are eliminated in the first year's disease-tolerant testing, leaving eight, select individual roots with high sugar content, large weight, and smooth surfaces and store them in cellars.

[0039] The following year, roots are inspected again as the grapes are removed from the cellar. Healthy, high-sugar, heavy, and free of rot mother roots are selected. These mother roots are then mixed and planted together for open pollination. Next, all flowering plants are selected for seedlings. The selection criteria are: high pollen yield, tall seedlings, good plant shape, plump pollen grains, and sufficient pollen. These selected individual plants are then listed for planting. Summer sowing is then carried out to cultivate the mother roots.

[0040] Year 3: The individual mother roots from the previous year's listing were spatially isolated and planted 5,000 meters apart. During flowering, the individual plants with high pollen counts were cut, bagged, self-pollinated, and listed. The seeds were harvested individually and sown in the summer to cultivate mother roots. At the same time, three different yield and quality lines, CMS1, CMS2, and CMS3 (sterile lines), were sown in the summer to cultivate mother roots.

[0041] Year 4: General combining ability tests were conducted on the mother roots of the lines formed the previous year. Specifically, the mother roots of different lines were planted together with three CMS1, CMS2, and CMS3 mother roots. Each line material was planted together with three sterile lines, 5,000 meters away from other lines, to provide spatial isolation. The line used as the male parent material was simultaneously self-pollinated to produce self-pollinated first-generation seed, S1, which was sown in summer to cultivate mother roots. Simultaneously, a CMS4, the best sterile line used in production at the time, was sown again in summer to cultivate mother roots.

[0042] In the fifth year, we planted the three CMS configurations identified in the previous year in spring. At the same time, we cultivated the mother roots of the self-pollinated first generation. In the summer, we planted a CMS4 with the best production and cultivated the mother roots.

[0043] In the sixth year, based on the identification results, the selected first-generation self-pollinated plant material mother roots are planted together and intercrossed during the flowering period to form Comprehensive Group 1. Seed plants are selected, sown in summer, and the mother roots are cultivated. This forms the mother roots of Comprehensive Group 1.

[0044] At the same time, the strain with the best general combining ability was test-crossed with the best CMS4 mother root from the previous year and then self-pollinated. This produced the second-generation seed, or S2. Two seed pools were harvested: one from the CMS4 and one from the S2 generated by the self-pollinated strain itself.

[0045] Year 7: Plant the parent roots of Synthetic Group 1 and the parent roots of the second-generation self-pollinated S2 plant to form Synthetic Group 2, and select seedlings. Harvest seeds, sow in summer, and cultivate the parent roots of Synthetic Group 2. Special combining ability tests are performed on seeds harvested from the previous year's CMS4 plant. The optimal combination is selected, and the strain corresponding to the male parent material becomes the new pollination strain.

[0046] In the eighth year, the parent roots of Synthetic Group 2, formed the previous year, were planted together with a newly introduced parent root of foreign material L to form the third generation Synthetic Group 3. Open pollination occurred during the flowering period, and seed plants were selected and listed. Seeds were harvested and the parent roots were cultivated to form the parent roots of Synthetic Group 3 (F1, F2, F3, and F4).

[0047] In the ninth year, new strains (G1, G2, G3, G4, etc.) enter a new round of selection procedures.

[0048] Example 2 Select the basic material according to the breeding goal. In terms of production quality, the basic material can be 6.5 tons / 667m 2 High yield, 15.5%-16.5% medium sugar content, or 16.5% or higher sugar content, yield 5.5-6.5 tons / 667m 2 Above average, but all have resistance to beet diseases, mainly beet root rot, rhizomes, and brown spot. In addition, the leaf cluster height is 40-50cm, the leaves are small, the leaf color is dark green, and the leaf area is 190-230cm 2 Suitable for modern agricultural mechanized harvesting. This is the most basic requirement for basic materials. This application is to select and breed new pollination lines, so the scope of basic materials is appropriately expanded according to the breeding goals. Previously bred materials are also included in the scope of basic materials. Doing so can further improve the quality of the materials, further tap the potential of existing germplasm resources, and create new materials.

[0049] In early April of the first year, in order to have a wider selection range, 10 new high-quality sugar beet varieties, including kws7748, kws3354, kws1231, kws7772, kws1479, kws0469, kws3928, kws6939, kws2935, and kws9147 (A1, A2, A3, A4...A10), were introduced and planted in the diseased beds. The external performance of each sugar beet variety was observed before harvest, mainly for the leaf height of 40-75 cm and the leaf area of ​​170-230 cm. 2 . Leaf color and leaf area are mainly reflected in leaf wrinkles and whether there are waves on the leaf edges. And whether it is disease-resistant, mainly rhizomes, root rot, brown spot, etc. Suppose: 10 varieties are introduced and planted in diseased beds. After the above series of observations and identifications, 9 varieties pass the test, and the other 1 is eliminated. Reason for elimination: not resistant to one of the diseases among rhizomes, root rot, and brown spot. The remaining 9 varieties are resistant to 3 diseases. Harvest in autumn, and then measure the yield and sugar content. In this link, the beet variety used in local production is ck, and beet varieties with higher yield and quality than it or equivalent to it are selected. The yield of ck is 6.5 tons / 667m 2 , with a sugar content of 16.0%. If eight varieties are selected, the reason for selection is: yield and sugar content greater than or equal to CK. One variety will be eliminated. The reason is: yield lower than CK (for field varieties) or sugar content lower than CK (for field varieties). From these eight selected varieties, 100 individual roots are selected for each variety. The selection criteria are: weight between 900g and 1200g, smooth roots, good root shape, shallow root grooves, and small root heads. The total number of mother roots for the eight varieties is 800. Then, they are mixed together and stored in a cellar.

[0050] In late March of the second year, remove the mother roots that are rotten and do not meet the requirements, and check the sugar content again. The sugar content standard at this time is ≥16%. The mother roots that do not meet the standard are removed. If there are 600 mother roots left. Then, plant these 600 mother roots in a spatial isolation area with a plant spacing of 50 cm and a row spacing of 40 cm. At this point, the preparation of the basic materials stops here. Of course, the pollination materials that have been cultivated can also be cultivated into mother roots and added to the mother root planting, or they can be not added and planted separately in spatial isolation as basic materials. This application is to add them to the large mother root planting area. During the flowering period, let the flowering plants pollinate each other freely, and observe the single plants with sufficient pollen. Specific description: During the peak flowering period, between 11 am and 6 pm, observe the pollen amount. Gently shake the flower branches with your hands, and the pollen will fall down in large quantities, or stroke the flower branches with your hands, and your hands will be stained with a large amount of pollen. This is a single plant with sufficient pollen. Use the same method for other individual plants. Those that do not exhibit the above symptoms are considered to have insufficient pollen. Label them with tags. If 300 plants in a planting area have good pollen counts, label them. Pull out all others. Harvest seeds from each of these 300 plants, and keep the tags with the seeds. Do not lose or mix them up. Between July 25th and August 5th of the same year, sow these 300 seed lots in the summer, with rows and plants 10 x 50 cm apart. Sow each lot in a separate plot. Cultivate mother roots. Then, harvest these mother roots in the autumn, from late October to early November. Label each lot, and collect those weighing more than 100 grams. Discard any remaining roots. Store the collected mother roots in a cellar according to the tags. Cover them with washed sand at a 60% moisture content and label them. Store each lot in a centralized storage location. Maintain a constant temperature of 1-5°C and humidity of 60%-80% within the cellar.

[0051] In the third year, 300 mother roots are taken out in late March of spring, and each mother root is planted in a separate space with an interval of 5000 meters between each mother root. During the flowering period, the pollen volume is observed again, and the standard for sufficient pollen volume is the same as above. Individual plants with poor pollen volume are eliminated. At this time, each mother root has multiple individual plants with good pollen volume, and then the flowers are cut, bagged and labeled, and the marking work is done well. Then, between July 25th and August 5th, sow again with a row spacing of 10×50cm, cultivate the mother roots, and the labels are carried along with the seeds, and they cannot be confused or lost. At the same time, the three summer sowing yields are ≥6 tons / 667m 2 Seeds of the sterile lines CMS1, CMS2, and CMS3 with a sugar content of 16% or higher were used. The amount of sterile line seeds was equivalent to the total amount of seeds from the 300 selected mother roots. The sowing time and method were the same as above. The mother roots were harvested and stored in a cellar.

[0052] In the fourth year, a general combining ability test was conducted. The mother root of each plant line was planted together with three sterile lines, 5,000 meters apart. Seeds were harvested from each sterile line, and 3 seeds were harvested from 3 sterile lines. The 3 seeds were then sown in spring for identification, and the average value was calculated. The specific method was as follows: each plant line material was planted together with three sterile lines, cms1, cms2, and cms3, with cms1 in one row, cms2 in one row, and cms3 in one row. The mother roots of the other plant lines were planted in one row on each side, surrounding the sterile line in the middle. The spacing between plants and rows was 20×30 cm, and free pollination and pollination were allowed during the flowering period. The same method was used for the mother roots of other plant lines. There needed to be a 5,000-meter spatial separation between them. If there were 8 such spatial isolation points, 8 self-pollinated first-generation seeds and 24 test-cross seeds would be produced. All 32 seeds should be labeled and marked. The final result was: in each isolation point, 4 seeds were harvested, 3 test cross seeds were harvested from three sterile lines, and one self-pollinated first-generation seed was harvested from the plant line.

[0053] In the fifth year, the seeds harvested from cms1, cms2, and cms3 were used for spring sowing identification. Specific procedures were as follows: 24 test cross seeds harvested and the variety currently planted in the field (ck) were sown in mid-April with a row spacing of 14.5 × 50 cm. Each test cross seed was sown in a separate plot of 50 m2. 2 ck was also sown in a similarly large plot, managed normally, and harvested in the fall. Yield and quality were then assessed. Specifically, 10 beets were randomly selected from the harvested material and the sugar content was measured individually. The average value was calculated. This was the sugar content of the testcross material. The beets produced from each testcross seed were weighed and converted to yield per mu based on the sown area. The sugar content and yield per mu represent the yield of the testcross seed. The 24 testcross seeds were paired with 8 individual mother roots. The sugar content and yield of the three testcross seeds corresponding to each mother root of each line were averaged. For example, using the mother root of line A1 as the male parent, testcross seeds harvested from the corresponding cms1, cms2, and cms3 were then assessed for yield. The yield values ​​of the cms1 testcross seed, cms2 testcross seed, and cms3 testcross seed were averaged to obtain an average value, B1. Thus, the eight mother roots of each line correspond to eight B values ​​(average values), B1-B8.

[0054] Based on the results, the parent root materials of the lines with average yield and quality exceeding the control are selected. If 18 are selected, then the corresponding (male) parents of these 18 are the promising materials. These are the six inbred lines with high combining ability. Generally, CMS1, CMS2, and CMS3 are combined with the line materials. Since the male parent materials are the same and have good performance, the seeds harvested from the CMS (sterile line) will show good yield and quality during spring sowing assessment. Therefore, CMS1, CMS2, and CMS3 are used to test the yield and quality of many line materials, and the results are used to judge the potential of the line materials. This is the general combining ability assessment of these line materials. This assessment is used to select materials with high combining ability. Simultaneously, these six line materials are self-pollinated while undergoing general combining ability assessment. Therefore, the six seeds harvested again are the self-pollinated first-generation seeds. Six self-pollinated first-generation seeds were sown between July 25 and August 5 of the same year with a spacing of 10×50 cm between rows and plants. Harvested in early November, the mother roots weighing more than 100 grams were selected, and the rest were discarded and stored in cellars. At the same time, the sugar content ≥16.5% and the yield ≥6 tons / 667m 2 The best sterile line cms4 was sown between July 25 and August 5 of the same year with a plant spacing of 10×50 cm. It was harvested in early November. Mother roots weighing more than 100 grams were selected and the rest were eliminated.

[0055] In the sixth year, six selfed first-generation mother roots were removed, and the top two performing best in general combining ability selection (the top two in B) were selected for testcrossing with the CMS4 mother roots cultivated the previous year. Specifically, each of the top two B mother roots was planted alongside CMS4, again spatially isolated at two isolation sites, 5000 meters apart. Within each isolation site, the CMS4 were planted together in one or more rows, while the male parent, B, was planted together in one or more rows, but the ratio of CMS4 to B was 3:1: that is, three rows of CMS4 were planted for the female parent and one row for the B. From the five isolation sites formed by the five B mother roots, five selfed second-generation seeds and two testcross seeds were harvested. These two selfed second-generation seeds were sown that summer, and mother roots were cultivated. The mother roots at this point became the selfed second-generation mother roots, and then cellared (the summer sowing, mother root selection, and cellaring procedures were the same as above).

[0056] The remaining self-pollinated first-generation mother roots are collectively planted that year to form Integrated Population 1. Free pollination is allowed within the population during the flowering period, and then seedlings are selected based on their tall stature and high pollen yield. The remaining seedlings are eliminated. Seeds from the selected seedlings are harvested that year, sown that summer, and mother roots are cultivated. These mother roots are considered the mother roots of Integrated Population 1.

[0057] In the seventh year, the combinations tested in the previous year were subjected to special combining ability testing. The specific method was: Two testcross seeds from the previous year's harvest were sown in mid-April in spring, with a spacing of 14.5 x 50 cm between rows. Two testcross seeds were sown in two plots, with a local production variety used as a control (CK). In the autumn, the seeds were harvested, sugar levels were tested and weighed in each plot to calculate the unit yield. The yield was then compared to the CK, and combinations with a yield exceeding CK were selected. The combination with the highest yield was deemed the optimal combination. The male parent of this optimal combination also served as the new pollination material. Simultaneously, the maternal roots of Synthetic Group 1 were mixed with the second-generation maternal roots from the selfed testcross, and planted together to form Synthetic Group 2. Free pollination occurred during flowering, and seed selection was repeated using the same method as above. Overall, the maternal roots from this generation became the maternal roots of Synthetic Group 2. Synthetic Group 1 was then intercrossed with the second-generation maternal roots from the selfed testcross, resulting in the formation of Synthetic Group 2, thus improving the genetic profile of Group 1. Synthetic Group 2 was also sown in the summer of the same year, and maternal roots were cultivated.

[0058] In the eighth year, a new hybrid root is introduced into Comprehensive Group 2 and planted together with the root from Group 2 to create Comprehensive Group 3. The specific method is as follows: the root stock is mixed before planting, then planted in rows with a spacing of 20 x 20 cm, and cross-pollinated during flowering. Seedling selection is then performed using the same method as above. The plants are then listed, seeds harvested from each plant, and the root stock is cultivated, entering a new round of selection. Generally, after screening for exceptional combining ability, new material and new genes are introduced to enrich the original group's genetic profile and increase the heterozygosity rate, thereby improving the original comprehensive group and laying a solid foundation for the next round of selection.

[0059] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements or improvements made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A method for breeding sugar beet male parents, characterized in that: The following steps are involved: In the first year, an original group A of 10 sugar beet varieties was selected and planted in the diseased garden for disease resistance selection; In the second year, the disease-resistant varieties selected will be mixed with mother roots, cross-bred with breeding plants, and selected for seed plants to obtain fertile plants. In the third year, seed selection is performed again on the fertile plant 1 obtained in step S2, and fertile plant 2 is obtained after cross-crossing of the small group. The fertile plant 2 is cut and bagged to form plant line B; In the fourth year, line B was mated with three sterile lines, and seeds were harvested for general combining ability evaluation. In the fifth year, the spring sowing yield quality assessment is carried out and each plant line is self-pollinated to form self-pollinated first-generation seeds; In the sixth year, the two mother roots of the materials selected after the general combining ability identification were mated with the best sterile line, and then the special combining ability identification and selection were carried out. The remaining self-pollinated first generation were planted together to form comprehensive group 1; In the seventh year, the seeds obtained by combining the two material mother roots in step S6 with the optimal sterile line are harvested in spring, and their yield and quality are assessed by special combining ability. The seeds obtained by the optimal combination are screened, and the male parent of the seeds obtained by the optimal combination is the created pollination line. At the same time, the two material mother roots in step S6 are self-pollinated to form self-pollinated second-generation seeds, which are planted together with the integrated population 1 to form the integrated population 2. In the eighth year, the mother roots of integrated group 2 were mixed with the mother roots of hybrid varieties of foreign materials to form integrated group 3, and seed selection was carried out on them; In the ninth year, the seed plants are selected to form a strain and the next round of selection is carried out.

2. The method for breeding a sugar beet male parent according to claim 1, characterized in that: In step S1, in early April of the first year, the original population A of 10 new sugar beet varieties was introduced and planted in the diseased garden. The external performance of each sugar beet variety was observed before harvest. The leaf height was 40-75 cm and the leaf area was 170-230 cm. 2 Leaf color and leaf area need to be observed for leaf wrinkles and leaf edge waves; disease resistance needs to be observed for resistance to rhizomania, root rot, and brown spot; after the autumn harvest, the yield and sugar content will be measured, using the local sugar beet variety with the largest production volume as the control, and selecting sugar beet varieties with a yield and quality exceeding or equivalent to it; For the new beet varieties selected, 100 single roots of each variety were picked. The selection criteria were: weight between 900g-1200g, smooth root body, good root shape, shallow root groove, small root head. All the mother roots were mixed and stored in the cellar.

3. The method for breeding a sugar beet male parent according to claim 1, characterized in that: In the step S2, in late March of the second year, rotten mother roots are removed and the sugar content is checked again. At this time, the sugar content standard is ≥16%, and the mother roots that do not meet the standard are removed. The mother roots that meet the standard are planted in a spatial isolation area with a plant spacing of 50 cm and a row spacing of 40 cm; during the flowering period, the plants are freely cross-pollinated, and the individual plants with sufficient pollen are observed and determined. The individual plants with sufficient pollen are marked and retained, and the rest are removed; between July 25 and August 5 of the same year, the individual plants retained for summer sowing are marked with a plant spacing of 10×50 cm, and each plant is sown separately in an area to cultivate the mother roots; from the end of October to the beginning of November, the mother roots with a weight greater than 100 g are harvested in autumn, and the rest are discarded. The mother roots are placed in a cellar and buried with washed sand with a moisture content of 60%, and the temperature in the cellar is 1-5°C and the humidity is 60%-80%.

4. The method for breeding a sugar beet male parent according to claim 1, characterized in that: In the step S3, the mother roots stored in step S2 are taken out in late March of the third year, and each mother root is planted in a separate space with an interval of 5000 meters between each mother root; during the flowering period, the individual plants with sufficient pollen are observed again and marked, and the individual plants with sufficient pollen are removed, and the flowers are cut, bagged and marked. Between July 25 and August 5 of the same year, the mother roots are sown with a spacing of 10×50 cm between rows and plants to cultivate the mother roots; at the same time, the yield of three summer sowings is ≥6 tons / 667m 2 , the mother roots of the sterile lines cms1, cms2, and cms3 seeds with a sugar content ≥16% were harvested and stored in cellars.

5. The method for breeding a sugar beet male parent according to claim 1, characterized in that: In the step S4, a general combining ability identification is performed in the fourth year, that is, the mother root of each plant line in step S3 is planted together with the three sterile lines cms1, cms2, and cms3, and the distance between them is 5,000 meters. Seeds are harvested from each sterile line, and 3 seeds are harvested from 3 sterile lines. The 3 seeds are then identified for spring sowing and the average value is calculated. In each isolation point, 4 seeds are harvested, 3 test cross seeds are harvested from the three sterile lines, and one self-pollinated first-generation seed is harvested from the plant line.

6. The method for breeding a sugar beet male parent according to claim 1, characterized in that: In step S5, the seeds harvested from cms1, cms2, and cms3 in the fifth year are subjected to spring sowing identification, normal management, and harvested in autumn; then, a yield and quality identification is performed, i.e., 10 beets are randomly selected from the harvested materials for single-plant sugar measurement to obtain the average value; the beets produced by each test cross seed are weighed and converted into per-acre yield based on the sown area; the sugar content and per-acre yield are the yield and quality of the test cross seeds; based on the results, the mother root material of the plant line with an average yield and quality better than the control is selected, and its corresponding father parent is the selected material with development prospects.

7. The method for breeding a sugar beet male parent according to claim 1, characterized in that: In the step S6, the two self-pollinated first-generation mother roots with the best performance in the general combining ability selection are selected in the sixth year, and are test-crossed with the optimal sterile line cms4 mother roots cultivated in step S5, and the self-pollinated second-generation seeds and the test-cross seeds are harvested respectively. The self-pollinated second-generation seeds are sown in the summer of the same year, and the self-pollinated second-generation mother roots are cultivated and stored in a cellar; the self-pollinated first-generation mother roots are concentratedly planted in the same year to synthesize the integrated population 1, and free open pollination is carried out within the population during the flowering period, and then seed plants are selected, and the dominant seed plants are selected, and the others are eliminated. The dominant seed plants are harvested in the same year, and the seed plants are sown in the summer of the same year and the mother roots are cultivated, which are the mother roots of the integrated population 1.

8. The method for breeding a sugar beet male parent according to claim 1, characterized in that: In the step S7, the combination tested in step S6 is subjected to a special combining ability identification test in the seventh year, and the specific method is as follows: the test cross seeds are sown in spring, and after harvest in autumn, the sugar content is measured and weighed, and the unit yield is calculated. After comparison with the control, a combination that exceeds the control is selected, and the optimal combination is determined by the yield. The male parent of the optimal combination is the pollination material; at the same time, the mother roots of the integrated group 1 and the self-pollinated second-generation mother roots formed by the test cross are mixed together, and planted together to synthesize the integrated group 2; free open pollination is carried out in the group during the flowering period, and then seed plants are selected, and the dominant seed plants are selected, and the others are eliminated. The seeds of the dominant seed plants are harvested in the same year, and the mother roots are sown and cultivated in the summer of the same year, which are the mother roots of the integrated group 2.

9. The method for breeding a sugar beet male parent according to claim 1, characterized in that: In step S8, in the eighth year, the integrated population 2 is mixed with the mother roots of another hybrid variety and planted to synthesize the integrated population 3.

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