Breeding method of new high-sugar sugarcane strain

Abstract

The invention relates to the technical field of sugarcane breeding, in particular to a sugarcane high-sugar new strain breeding method which comprises the following steps: step 1, parent selection; step 2, directional hybridization; step 3, culturing and screening; the screened sugarcane plants P2 are subjected to a salt stress environment of 60mM sodium chloride in the elongation stage, sugarcane plants P3 with the stem Brix value decreased by less than or equal to 3% and the plant height larger than or equal to 2 m are reserved, the sugarcane plants P3 are transplanted to three different test points respectively, and through a ratoon property test, the yield of the sugarcane plants P3 is increased by more than or equal to 3%. The sucrose content in the mature period is larger than or equal to 20%, and the hectare sugar yield is larger than or equal to 12 tons. According to the method disclosed by the invention, through integrated innovation of technologies of precise parent selection, photoperiod regulation and control directional hybridization, multi-stage strict cultivation and screening and multi-environmental stress verification, traditional breeding limitation is broken through, sugar genetic potential and stress resistance are improved, and efficient and precise breeding is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of sugarcane breeding, and specifically relates to a method for breeding a new high-sugar sugarcane strain. Background Art

[0002] As an important sugar crop globally, the sucrose content of sugarcane is directly related to the efficiency and competitiveness of the sugar industry. With the continuous growth of the market demand for sucrose and the increasing requirements of sugar enterprises for raw material quality, cultivating high-sugar sugarcane varieties has become a key goal in the field of sugarcane breeding. High-sugar sugarcane varieties can not only increase the sugar yield per unit area, increase the economic income of growers, but also meet the demand of sugar enterprises for high-quality raw materials, reduce production costs, and improve the economic benefits of the entire sucrose industry. In addition, in the case of limited land resources, increasing the sugar content of sugarcane is an effective way to improve the overall efficiency of the sugarcane industry, and it also has important significance for ensuring the national sugar supply security. Therefore, it is urgent to carry out the breeding work of new high-sugar sugarcane strains.

[0003] There are many deficiencies in the current sugarcane breeding technology for the selection of new high-sugar strains. Firstly, the selection of parents lacks precision. Traditional breeding often does not fully consider the comprehensive advantages of the sugar content and other traits of parents, resulting in limited genetic potential for sugar in the offspring, making it difficult to break the limitation that sugar and stress resistance cannot coexist, and unable to effectively improve the sugar level of sugarcane varieties. Secondly, there is a lack of effective technical means to ensure synchronous flowering of parents during the hybridization process, and the hybridization success rate is low, increasing the breeding cost and time cycle. Moreover, in the cultivation and screening link, existing technologies mostly use traditional screening methods and standards, with a long screening cycle, and it is difficult to accurately and efficiently screen target traits, and it is impossible to dynamically eliminate weak plants, resulting in poor trait stability of the selected varieties. In addition, existing breeding technologies lack comprehensive verification of multi-ecological region environments. The selected varieties often only show good sugar traits in specific environments, with insufficient sugar stability and stress resistance under different environmental conditions, high planting risks, and limited applicable promotion areas. Therefore, a method for breeding a new high-sugar sugarcane strain is proposed. Summary of the Invention

[0004] To solve the above problems, the present invention provides a method for breeding a new high-sugar sugarcane strain. Through the integrated innovation of precise parent selection, photoperiod-regulated directional hybridization, multi-stage strict cultivation and screening, and multi-environment stress verification, the limitations of traditional breeding are broken, the genetic potential for sugar and stress resistance are improved, and efficient and precise breeding is achieved.

[0005] To achieve the above object, the technical solution of the present invention is as follows: A method for breeding a new high-sugar sugarcane strain, comprising the following steps:

[0006] Step 1, Parent Selection: Select sugarcane varieties with a sugar content of ≥15% as the male and female parents for hybridization;

[0007] Step 2, Directed Hybridization: Induce synchronous flowering of the male and female parents through photoperiod regulation, and hybridize and seed the male and female sugarcane through artificial pollination to obtain 1 hybrid spike;

[0008] Step 3, Cultivation and Screening: Sow and cultivate the hybrid seeds with sterilized soil as the substrate in the greenhouse. Transplant the seedlings with more than 3 leaves grown out to the seedling trays for temporary planting, and then transplant them to the field after 30 - 40 days to form a hybrid nursery. Conduct a preliminary screening of the hybrid nursery according to Standard 1 to obtain a preliminary screening nursery. Conduct a re-screening of the sugarcane at the maturity stage in the preliminary screening nursery according to Standard 2, and select the sugarcane plants P1 that will enter the seed selection nursery in the following year;

[0009] Step 4, Intermediate Seed Selection Nursery: Transplant the sugarcane plants P1 to the field. Measure the growth rate of the stem Brix value ≥0.4% / week during the tillering stage, and control the soil water content at 50% for screening. Select the sugarcane plants P2 with a survival rate ≥90% and meeting Standard 3 to enter the next round of seed selection nursery;

[0010] Step 5, Advanced Seed Selection Nursery: For the selected sugarcane plants P2, simulate a salt stress environment of 60 mM sodium chloride during the elongation stage for 10 days. Retain the sugarcane plants P3 with a decrease in stem Brix value ≤3% and a plant height ≥2 m. Transplant the sugarcane plants P3 to three different test sites respectively. Finally, after the ratooning ability test, select the stable lines with a sucrose content ≥20% and a hectare sugar yield ≥12 tons at maturity.

[0011] Furthermore, in Step 1, the preferred criteria for the female parent are: a sugar content of 15% - 18%, a stem diameter of 2.8 - 3.2 cm, a susceptible variety to smut with a smut incidence ≥30%, and a ratooning plant rate between 60% - 80% in the following year, and can be continuously planted for 2 - 3 years;

[0012] The preferred criteria for the male parent are: a sugar content ≥18% and drought resistance.

[0013] Furthermore, in Step 2, the photoperiod regulation is 14 - hour light per day, and after pollination, isolate and culture until the seeds mature.

[0014] Furthermore, in Step 3, the greenhouse conditions are a temperature of 20 - 35°C, a humidity of 60% - 100%, the pore size distribution of the seedling trays is 5x10 holes or 6x10 holes, and when transplanting to the field, plant according to a row spacing of 1.2 m and a plant spacing of 0.3 m.

[0015] Furthermore, in Step 3, the first standard for preliminary screening is selected as: select single plants with a stem diameter ≥5 mm, upright leaves and no disease spots at the seedling stage, and the retention rate ≤30.

[0016] Furthermore, in step three, the second criterion for reselection is: plant height ≥2.5m, stem diameter ≥2.5cm, number of harvested stems formed by effective tillers per plant ≥2, leaf shedding ratio at maturity ≥70%, and Brix value ≥16% of the strains are determined and retained.

[0017] Furthermore, in step 4, the Brix value increase rate is achieved by non-destructive testing of the middle stalks of the sugarcane plants using near-infrared spectroscopy once a week.

[0018] Furthermore, in step 4, the third screening criterion is selected as follows: the sugarcane plant P2 line satisfies the coefficient of variation of stem diameter ≤ 5% and the stem fiber content ≤ 12%.

[0019] Furthermore, in step five, the environments of the three test sites are: tropical with an average annual temperature ≥ 24°C, subtropical with an average annual temperature of 18-24°C, and semi-arid with an annual rainfall ≤ 800 mm.

[0020] Furthermore, in step five, the ratoon test is that the sugar content of the sugarcane stubble after three consecutive years of stubble retention decreases by ≤1.5%, and the number of stalks per hectare is ≥70,000.

[0021] The above scheme has the following beneficial effects:

[0022] 1. This plan, by selecting a female parent with high sugar content, strong perennial rooting and moderate sacrifice of disease resistance, and conducting directed hybridization with a high sugar and drought-resistant male parent, breaks the limitation of traditional breeding that sugar and stress resistance cannot coexist, significantly improves the sugar genetic potential of the offspring, and at the same time compensates for the disease resistance shortcomings through perennial rooting, ensuring the long-term stability and adaptability of the variety.

[0023] 2. This program dynamically eliminates weak plants through non-destructive testing and environmental stress (such as salt stress and water control), significantly shortens the screening cycle and improves the stability of target traits. It simultaneously verifies the performance of varieties in multiple ecological regions such as tropical, subtropical, and semi-arid areas, and combines salt stress, drought simulation and other adversity screening to ensure the sugar stability and stress resistance of the selected varieties in different environments, reduce planting risks, and expand the applicable areas for promotion.

[0024] 3. This scheme uses photoperiod regulation to achieve synchronous flowering of parents, thereby improving the success rate of hybridization; uses near-infrared spectroscopy technology to non-destructively monitor sugar dynamics and reduce plant damage; and precisely controls environmental parameters such as soil moisture content and salt stress intensity to achieve standardization and repeatability of phenotypic screening, significantly shortening the breeding cycle.

[0025] 4. This program selects strains with uniform stems, low fiber content, and easily detached leaves, reducing the difficulty of mechanized harvesting and energy consumption in sugar mills, thereby improving sugar production efficiency. Furthermore, perennial root testing ensures the sustainable cultivation of these varieties, reduces farmers' replanting costs, and promotes cost reduction and efficiency improvement across the entire supply chain.

[0026] Additional aspects and advantages of the present invention will be given in part in the following description, become apparent in part from the following description, or be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the method steps of an embodiment of the method for breeding a new high-sugar sugarcane strain of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0028] The technical solutions of the present invention will be described clearly and completely below with reference to the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0029] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be understood as a limitation of the present invention. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0030] In the description of the present invention, it should be noted that unless otherwise clearly defined and limited, the terms "installed", "connected", "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0031] The following will be further described in detail through specific embodiments:

[0032] Example 1:

[0033] As shown in the attached Figure 1 figures: A method for breeding a new high-sugar sugarcane strain includes the following steps:

[0034] Step 1, Parent Selection: Select sugarcane varieties with a sugar content ≥ 15% as the male and female parents for hybridization. The preferred criteria for the female parent are: sugar content of 15% - 18%, stem diameter of 2.8 - 3.2 cm, a susceptible variety to smut with a smut incidence ≥ 30%, and the ratoon plant rate in the next year between 60% - 80%, and it can be continuously planted for 2 - 3 years; the preferred criteria for the male parent are: sugar content ≥ 18% and drought resistance.

[0035] Step 2, Directed Hybridization: Induce the male and female parents to bloom synchronously through photoperiod regulation. The photoperiod regulation is 14 hours of light per day. After pollination, isolate and culture until the seeds mature. Hybridize the male and female sugarcane through artificial pollination to obtain 1 hybrid spike.

[0036] Step 3, Cultivation and Screening: Under the greenhouse conditions with a temperature of 20 - 35°C and a humidity of 60% - 100%, use sterilized soil as the substrate to sow and cultivate the hybrid seeds. Pot the seedlings with more than 3 leaves on a seedling tray with a pore size distribution of 5x10 holes or 6x10 holes. After 30 - 40 days, transplant them to the field at a row spacing of 1.2 m and a plant spacing of 0.3 m to form a hybrid nursery. Conduct a preliminary screening of the hybrid nursery according to the standard. The first standard for the preliminary screening is to select single plants with a stem diameter ≥ 5 mm, upright leaves and no disease spots at the seedling stage, and the retention rate ≤ 30 to obtain a preliminary screening nursery. Conduct a re-screening of the sugarcane at the mature stage in the preliminary screening nursery according to the second standard. The second standard for the re-screening is: the plant height ≥ 2.5 m, the stem diameter ≥ 2.5 cm, the number of harvested stems formed by single-plant effective tillering ≥ 2, the leaf shedding ratio at the mature stage ≥ 70%, measure the Brix value and retain the plant lines with ≥ 16% to select the sugarcane plants P1 that enter the seed selection nursery in the next year.

[0037] Step 4, Intermediate Seed Selection Nursery: Transplant the sugarcane plants P1 to the field. Measure the Brix value growth rate of the stem ≥ 0.4% / week during the tillering stage. The Brix value growth rate is achieved by non-destructively detecting the middle stem of the sugarcane plant by near-infrared spectroscopy once a week, and control the soil water content at 50% for screening. Select the sugarcane plants P2 with a survival rate ≥ 90% and meeting the third standard to enter the next round of seed selection nursery. The third standard for the screening is: the plant line of the sugarcane plants P2 meets a stem diameter coefficient of variation ≤ 5% and a stem fiber content ≤ 12%.

[0038] Step 5, Advanced Seed Selection Nursery: For the selected sugarcane plants P2, simulate a salt stress environment of 60 mM sodium chloride during the elongation period for 10 days. Retain the sugarcane plants P3 with a decrease in the Brix value of the stem ≤ 3% and a plant height ≥ 2 m. Transplant the sugarcane plants P3 to three different test sites, and the environments of the three test sites are as follows: tropics with an average annual temperature ≥ 24°C, subtropics with an average annual temperature of 18 - 24°C, and semi-arid areas with an annual rainfall ≤ 800 mm. Finally, after the sugar content of the sugarcane stubble decreases ≤ 1.5% after three consecutive years of stubble retention and the ratooning ability test with a number of stems per hectare ≥ 70,000, select stable lines with a sucrose content ≥ 20% and a sugar yield per hectare ≥ 12 tons at maturity.

[0039] Take the sugarcane variety bred according to this example as the experimental group, and select a sugarcane variety with a sucrose content ≥ 20% on the market as the control group. Conduct experiments for three consecutive years in the subtropical region with an average annual temperature of 18 - 24°C to obtain the following agronomic trait performances:

[0040] Table 1 Comparison of Agronomic Trait Performances

[0041]

[0042] As can be seen from Table 1, in this example, when the sucrose content of the experimental group is comparable to that of the control group, the germination rate of the experimental group is higher than that of the control group, and the ratooning plant emergence rate is high, with an average of 150.7%, which is 41.25% higher than that of the control group. The tillering rate is average, the early growth is faster, the jointing is earlier, and because it has experienced salt stress screening during the elongation period, it can better adapt to various soil environments. The growth during the elongation period is vigorous, the growth potential of the plants is sufficient, the plants are taller, the stem formation rate is high, and the number of effective stems is large, with an average of 74,698 stems / hm 2 , which is 23.64% more than that of the control group.

[0043] Obviously, the above examples are only illustrations for clear explanation and not limitations on the implementation methods. For those of ordinary skill in the art, other different forms of changes or variations can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. And the obvious changes or variations derived therefrom are still within the protection scope of the present invention.

Claims

1. A breeding method for a new high-sugar sugarcane strain, characterized in that, It includes the following steps: Step 1, Parent selection: Select sugarcane varieties with a sugar content ≥ 15% as the male and female parents for hybridization; Step 2, Directed hybridization: Induce the male and female parents to bloom synchronously through photoperiod regulation, and hybridize and produce seeds by artificial pollination between the male and female sugarcanes to obtain 1 hybrid spike; Step 3, Cultivation and screening: Using sterilized soil as the substrate in the greenhouse, sow and cultivate the hybrid seeds. Pot the seedlings with more than 3 leaves on the seedling tray, and transplant them to the field after 30 - 40 days to form a hybrid nursery. Conduct a preliminary screening of the hybrid nursery according to Standard 1 to obtain a preliminary screening nursery. Conduct a re-screening on the sugarcanes at the maturity stage in the preliminary screening nursery according to Standard 2, and select the sugarcane plants P1 that will enter the seed selection nursery in the next year; Step 4, Intermediate seed selection nursery: Transplant the sugarcane plants P1 to the field. Measure the growth rate of the Brix value of the stem ≥ 0.4% / week during the tillering stage, and control the soil water content at 50% for screening. Select the sugarcane plants P2 with a survival rate ≥ 90% and meeting Standard 3 to enter the next round of seed selection nursery; Step 5, Advanced seed selection nursery: For the selected sugarcane plants P2, simulate a salt stress environment of 60 mM sodium chloride during the elongation stage for 10 days. Retain the sugarcane plants P3 with a decrease in the Brix value of the stem ≤ 3% and a plant height ≥ 2 m. Transplant the sugarcane plants P3 to three different test sites respectively. Finally, after the ratooning ability test, select the stable lines with a mature sucrose content ≥ 20% and a sugar yield per hectare ≥ 12 tons; 2. The breeding method of the new high-sugar sugarcane strain according to claim 1, characterized in that, In Step 1, the preferred criteria for the female parent are: a sugar content of 15% - 18%, a stem diameter of 2.8 - 3.2 cm, a susceptible variety to smut with a smut incidence ≥ 30%, and a ratooning rate between 60% - 80% in the following year, and can be continuously planted for 2 - 3 years; The preferred criteria for the male parent are: a sugar content ≥ 18% and drought resistance; 3. The breeding method of the new high-sugar sugarcane strain according to claim 2, characterized in that, In Step 2, the photoperiod regulation is 14 hours of light per day, and after pollination, isolate and culture until the seeds mature; 4. The breeding method of the new high-sugar sugarcane strain according to claim 3, characterized in that In Step 3, the greenhouse conditions are a temperature of 20 - 35°C, a humidity of 60% - 100%, the pore size distribution of the seedling tray is 5x10 holes or 6x10 holes, and when transplanting to the field, plant according to a row spacing of 1.2 m and a plant spacing of 0.3 m; 5. The breeding method of the new sugarcane high-sugar strain according to claim 4, characterized in that, [[ID=AB]]In Step 3, the first standard for preliminary screening is to select single plants with a stem diameter ≥ 5 mm, upright leaves and no disease spots at the seedling stage, and the retention rate ≤ 30; 6. The breeding method of the new high-sugar sugarcane strain according to claim 5, characterized in that, In Step 3, the second standard for re-screening is: plants ≥ 2.5 m, a stem diameter ≥ 2.5 cm, the number of harvested stems formed by effective tillers per single plant ≥ 2, the leaf shedding ratio at maturity ≥ 70%, measure the Brix value and retain the lines ≥ 16%; 7. The breeding method of the new high-sugar sugarcane strain according to claim 6, characterized in that, In Step 4, the growth rate of the Brix value is achieved by non-destructively detecting the middle stem of the sugarcane plant by near-infrared spectroscopy once a week; 8. The breeding method of the new high-sugar sugarcane strain according to claim 7, characterized in that, In Step 4, the third standard for screening is: the lines of the sugarcane plants P2 meet a stem diameter coefficient of variation ≤ 5% and a stem fiber content ≤ 12%; 9. The breeding method of the new sugarcane high-sugar strain according to claim 8, characterized in that, In Step 5, the environments of the three test sites are: the tropics with an annual average temperature ≥ 24°C, the subtropics with an annual average temperature of 18 - 24°C, and the semi-arid region with an annual rainfall ≤ 800 mm.

10. The breeding method of the new sugarcane high-sugar strain according to claim 9, characterized in that, In Step 5, the ratooning test requires that after three consecutive years of stubble retention, the sugar content decline of the sugarcane stubble is ≤ 1.5%, and the number of stems per hectare is ≥ 70,000.

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