Method for efficiently breeding by using wild germplasm

Abstract

The invention discloses a method for efficiently breeding by using wild germplasm, and relates to the technical field of agricultural breeding, the method comprises the following steps: hybridizing Guangdong 93-159 as a female parent and GXAS07-6-1 containing saccharum arundinaceum and hemsleya amabilis consanguinity as a male parent to obtain a hybrid A; using cinnamyl sugar 05-164 as a female parent to hybridize with the hybrid A to obtain a hybrid B; hybridizing Guitan 29 serving as a female parent with the hybrid seed B to obtain a hybrid seed C; according to the method, the low-fertility sugarcane variety with poor pollen scattering, low pollen development rate and high sugar content and the high-fertility wild sugarcane with adaptability, disease resistance, cold resistance, high drought resistance and low sugar content are selected as parents for cross breeding, and the high fertility and high resistance of the wild sugarcane make up for the defect of insufficient breeding capacity of the low-fertility sugarcane variety; the breeding efficiency is improved by using wild germplasm, and the obtained hybrid variety is high in sugar, has many effective stems, good growth vigor, strong smut resistance and obvious super-parent advantage.

Description

Technical Field

[0001] The present invention relates to the technical field of agricultural breeding, and in particular to a method for efficient breeding using wild germplasm. Background Art

[0002] Wild sugarcane germplasm harbors numerous excellent traits, such as clumping, perennial rooting, adaptability, disease resistance, cold tolerance, and drought tolerance. Using wild germplasm for distant hybridization with cultivated stock is crucial for broadening the genetic base of cultivated varieties and selecting breakthrough, superior varieties or superior parents. For many years, sugarcane breeders worldwide have hybridized cultivated and tropical varieties with wild species such as Scutellaria serrata, Imperata serrata, Hebawang, and Glechoma yunnanensis, producing a large number of distant hybrid progenies. However, because cultivated and tropical varieties are slow to flower, exhibit significant variations in flowering time, poor pollen shedding, and low pollen development rates, while wild germplasm flowers easily and early. Crossing wild germplasm with conventional parents often results in flowering mismatches, hindering breeding efficiency. Furthermore, because these hybrids originate from different species and genera and are distantly related, pollen fertility in these hybrids is generally low, or even infertile, hindering the efficient and innovative use of sugarcane germplasm.

[0003] Sugarcane smut, also known as whip smut or powdery mildew, is caused by the fungus Ustilago saccharina. It is a common disease in my country's sugarcane-growing areas, particularly affecting ratoon sugarcane and fields planted for many years. The disease's most distinctive characteristic is a downward-curling, inward-curling black whip at the tip of the affected sugarcane, ranging from several centimeters to tens of centimeters in length. The whip's center consists of a core composed of parenchyma or vascular tissue, surrounded by a layer of thick-walled spores. In its early stages, the whip is covered in a silvery-white membrane, which then ruptures, releasing a large amount of black powder, leaving only the core. Infected sugarcane plants germinate early, have small stems, slender, light green leaves, and an increased number of tillers, with later tillers also developing whips. Smut not only reduces sugarcane yield but also reduces the sugar content, impacting quality. Newly planted sugarcane and ratoon sugarcane affected by smut can reduce yield by 30%-50% and 52%-75%, respectively. Breeding sugarcane varieties resistant to black smut is of great significance to promoting the healthy and steady development of the industry and ensuring sugar safety.

[0004] Patent No. CN114916435A discloses a breeding method for obtaining high-brix, ultra-high-sugar sugarcane germplasm using Chinese germplasm. The method involves hybridizing Barwilspt as the female parent and Henan Xuchang sugarcane as the male parent to obtain hybrid A. Hybrid B is hybridized with POJ213 as the female parent. Hybrid C is hybridized with hybrid B using CP94-1100 as the female parent. Hybrid C, a high-sugar parent containing Chinese germplasm, can be used to obtain high-brix, ultra-high-sugar sugarcane germplasm. While this invention can produce sugarcane with high braxity and high sugar content, it does not address the issue of sugarcane resistance to smut.

[0005] Therefore, it is necessary to explore a method for efficient breeding using wild sugarcane species. Summary of the Invention

[0006] To address the above shortcomings, the present invention provides a method for efficient breeding using wild germplasm. This method utilizes the high fertility of wild sugarcane to solve the problems of cultivated and tropical varieties that are difficult to flower, have large differences in flowering periods, poor pollen shedding, and low pollen development rates, thereby improving hybridization efficiency. The high resistance of wild sugarcane is used to improve the resistance of offspring, while also regulating the flowering period, further promoting efficient breeding of wild germplasm. The hybrid varieties obtained by the present invention have high sugar content, many effective stems, good growth potential, strong resistance to smut, and obvious super-parent advantages. The specific technical solutions are as follows:

[0007] A method for efficient breeding using wild germplasm, comprising the following steps:

[0008] Hybrid A was obtained by crossing Yuetang 93-159 as the female parent and GXAS07-6-1, which has the bloodline of Imperata serrata and Scutellaria serrata, as the male parent.

[0009] Hybrid B was obtained by crossing Hybrid A with Guitang 05-164 as the female parent;

[0010] Hybrid C was obtained by hybridizing Guitang 29 with hybrid B.

[0011] Furthermore, the breeding method specifically comprises the following steps:

[0012] Parent selection: First, Yuetang 93-159 was used as the female parent, and GXAS07-6-1, which has the bloodline of Imperata serrata and Scutellaria baicalensis, was used as the male parent; then Guitang 05-164 and Guitang No. 29 were selected as recurrent parents;

[0013] Parent treatment: Plant the male parent GXAS07-6-1 in barrels in mid-to-late June, and plant in batches every other week. One month before the sugarcane blooms, phimosis the female parent to promote rooting. Select parents with the same flowering period for hybridization.

[0014] Hybrid seed treatment: After hybridization, the hybrid seeds are subjected to after-ripening treatment to obtain treated hybrid seeds;

[0015] Seedling sowing: In March or April, place the seedling medium in the seedling box, then evenly sow the sugarcane seeds on the seedling box for sowing. After the seedlings grow 3-5 true leaves, they are transplanted.

[0016] Hybrid nursery screening: Transplant the transplanted seedlings to the field in May-June, and select them at the end of the year or the beginning of the next year when the sugarcane is mature. Select plants with excellent performance based on the number of effective stems, hammer hardness, disease resistance, and sugar content.

[0017] Furthermore, in the seedling sowing step, the seedling medium is prepared by: selecting nutrient-rich soil, crushing it, sieving it, mixing it in a mass ratio of soil: organic matter: fine sand = 7:2:1, and then sterilizing it in a disinfection cabinet at 120°C for 2 hours, thereby obtaining the obtained medium;

[0018] Furthermore, in the parent treatment step, the method for regulating flowering period comprises the following steps:

[0019] S1, night light stage, the male parent is treated with night light to delay the flowering period to coincide with the flowering period of the female parent. From mid-July to mid-September, light is applied after sunset every day for 40-60 minutes, and the treatment lasts for 55-60 days;

[0020] S2, the night light-off stage, the male parent began to be treated with night light from mid-September, and was illuminated with a light source from 0:00 to 4:00 every morning. The light intensity was controlled at 100-150Lx from 0:00 to 2:00 in the morning, and 50-80Lx from 2:00 to 4:00 in the morning, and the treatment lasted for 15-25 days;

[0021] S3, light reduction treatment stage: light reduction treatment is carried out after the night light treatment is completed. The lighting time during 0:00-2:00 in the morning and 2:00-4:00 in the morning is reduced by 2 minutes every day. The light intensity during 0:00-2:00 in the morning is controlled to 80-100Lx, and the light intensity during 2:00-4:00 in the morning is controlled to 30-60Lx. The treatment continues for 10-15 days.

[0022] Furthermore, in step S1, the light intensity after sunset is 10-30 Lx.

[0023] Furthermore, the step S2 further includes controlling the temperature of the nighttime illumination treatment stage to be 28-30° C., and the temperature of the remaining illumination treatment stages to be at atmospheric temperature.

[0024] Furthermore, the method for regulating flowering period also includes water stress, wherein the male parent is soaked in water three times in late August, late October and late November, with an interval of 2-3 days between each soaking treatment. The soaking treatment adopts automatic drip irrigation, and the drip irrigation time is 3-4 hours.

[0025] Furthermore, the hybrid seed processing step specifically includes:

[0026] The hybrid seeds were placed in a cold storage for ripening. The temperature of the cold storage was controlled at 1-3°C. The ripening time was 3-5 days. After the ripening was completed, they were soaked in warm water at 40-50°C for 2-3 days. The water was changed every 12 hours. Before sowing, the seeds were soaked in a mixed reagent of methyl salicylate 2-4 mg / L, tebuconazole 5-10 mg / L, and 2,4-dichlorophenoxyacetic acid 1-3 mg / L for 1-2 days. The seeds were then removed and drained to obtain the treated hybrid seeds.

[0027] Furthermore, the ratio of the mixed reagent to seeds is 1L:15-20kg.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] 1. The present invention provides a method for efficient breeding using wild germplasm. This method utilizes wild germplasm to improve breeding efficiency. Low-fertility sugarcane varieties with poor pollen shedding, low pollen development rate, and high sugar content are selected with high-fertility wild sugarcane varieties that are adaptable, disease-resistant, cold-resistant, drought-resistant, and low in sugar content as parents for hybrid breeding. The high fertility of wild sugarcane compensates for the difficulties of cultivated and tropical varieties in flowering, with large differences in flowering periods, poor pollen shedding, and low pollen development rates. This improves hybridization efficiency, utilizes the high resistance of wild sugarcane to improve the resistance of offspring, and simultaneously regulates the flowering period, further promoting efficient breeding of wild germplasm. The hybrid varieties obtained by the present invention have high sugar content, abundant effective stems, good growth potential, strong smut resistance, and significant super-parent advantages.

[0030] 2. The present invention can accurately regulate the flowering period of wild species through light treatment in the night light stage, the night light-off stage, and the light reduction treatment stage, and postpone the flowering period of wild species to meet the cultivated species. The night light stage simulates the photoperiod changes in the natural environment. The night light-off stage and the light reduction treatment stage regulate hormone and metabolic synthesis, delay flower bud differentiation and delay flowering; mild water stress can promote the physiological response of wild species, prolong the flowering period, and improve the accuracy and stability of flowering period regulation by adjusting the soil moisture conditions. The flowering period of the male parent GXAS07-6-1 is postponed from early November to early December to mid-January.

[0031] 3. In the seed treatment step of the present invention, the seeds are first placed in a cold storage for low-temperature treatment at 1-3°C for after-ripening, and then soaked in warm water at 40-50°C after the seeds are taken to promote physiological maturation of the seeds. Warm water soaking can soften the seed coat and improve the water absorption and germination ability of the seeds. Before sowing, a mixed reagent of 2-4 mg / L of methyl salicylate, 5-10 mg / L of tebuconazole, and 1-3 mg / L of 2,4-dichlorophenoxyacetic acid is used to soak the seeds. Soaking in the mixed reagent can further improve the disease resistance and vitality of the seeds, and ultimately ensure that the seeds can germinate quickly and grow healthily after sowing, thereby improving the germination rate of the seeds, and the germination rate of hybrid seeds can be increased to more than 90%. DETAILED DESCRIPTION

[0032] The specific embodiments of the present invention are described in detail below, but it should be understood that the scope of protection of the present invention is not limited by the specific embodiments. Unless otherwise defined, all technical terms used hereinafter have the same meaning as those generally understood by those skilled in the art. The technical terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention. Unless otherwise specified, the various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or can be prepared by existing methods.

[0033] GXAS07-6-1 of the embodiment of the present invention is a GXAS07-6-1 complex of GXAS07-6-1 containing two wild germplasm lines of GXAS07-6-1 and GXAS07-6-1 obtained by hybridizing GXA87-7, a close relative of sugarcane, with GXS79-9, a close relative of sugarcane, Guangxi GXAS07-6-1.

[0034] Example 1

[0035] A method for efficient breeding using wild germplasm, comprising the following steps:

[0036] Hybrid A was obtained by crossing Yuetang 93-159 as the female parent and GXAS07-6-1, which has the bloodline of Imperata scabra and Scutellaria baicalensis, as the male parent; hybrid B was obtained by crossing Guitang 05-164 as the female parent with hybrid A; hybrid C was obtained by crossing Guitang 29 as the female parent with hybrid B.

[0037] 1. Parent treatment: Plant the male parent GXAS07-6-1 in barrels in mid-to-late June and plant in batches every week; one month before the sugarcane blooms, phimosis the female parent to promote rooting; select parents with the same flowering period for hybridization.

[0038] 2. Hybrid seed processing: After hybridization, the hybrid seeds are processed and placed in a cold storage for ripening. The temperature of the cold storage is controlled at 2°C and the ripening time is 4 days to obtain the processed hybrid seeds.

[0039] 3. Seedling sowing: In March, the seedling medium is placed in the seedling box, and then the hybrid seeds are evenly sown on the seedling box for sowing. After the seedlings grow 4 true leaves, they are transplanted; the preparation method of the seedling medium is: select nutrient-rich soil, crush and sieve it, and mix it according to the mass ratio of soil: organic matter: fine sand = 7:2:1, and then sterilize it in a disinfection cabinet at 120℃ for 2h.

[0040] 4. Hybrid nursery screening: Transplant the transplanted seedlings to the field in May and select them at the end of the year or the beginning of the next year when the sugarcane is mature. Select plants with excellent performance based on the number of effective stems, hammer hardness, disease resistance, and sugar content.

[0041] Example 2

[0042] A method for efficient breeding using wild germplasm, comprising the following steps:

[0043] Hybrid A was obtained by crossing Yuetang 93-159 as the female parent and GXAS07-6-1, which has the bloodline of Imperata scabra and Scutellaria baicalensis, as the male parent; hybrid B was obtained by crossing Guitang 05-164 as the female parent with hybrid A; hybrid C was obtained by crossing Guitang 29 as the female parent with hybrid B.

[0044] 1. Parent treatment: Plant the male parent GXAS07-6-1 in barrels in mid-to-late June and plant in batches every week; one month before the sugarcane blooms, phimosis the female parent to promote rooting; select parents with the same flowering period for hybridization.

[0045] 2. Hybrid seed processing: After hybridization, the hybrid seeds are processed and placed in a cold storage for ripening. The temperature of the cold storage is controlled at 1°C and the ripening time is 3 days to obtain the processed hybrid seeds.

[0046] 3. Seedling sowing: In April, the seedling medium is placed in the seedling box, and then the hybrid seeds are evenly sown on the seedling box for sowing. After the seedlings grow 5 true leaves, they are transplanted; the preparation method of the seedling medium is: select nutrient-rich soil, crush and sieve it, and mix it according to the mass ratio of soil: organic matter: fine sand = 7:2:1, and then sterilize it in a disinfection cabinet at 120℃ for 2h.

[0047] 4. Hybrid nursery screening: Transplant the transplanted seedlings to the field in June and select them at the end of the year or the beginning of the next year when the sugarcane is mature. Select plants with excellent performance based on the number of effective stems, hammer hardness, disease resistance, and sugar content.

[0048] Example 3

[0049] A method for efficient breeding using wild germplasm, comprising the following steps:

[0050] Hybrid A was obtained by crossing Yuetang 93-159 as the female parent and GXAS07-6-1, which has the bloodline of Imperata scabra and Scutellaria baicalensis, as the male parent; hybrid B was obtained by crossing Guitang 05-164 as the female parent with hybrid A; hybrid C was obtained by crossing Guitang 29 as the female parent with hybrid B.

[0051] 1. Parent treatment: Plant the male parent GXAS07-6-1 in barrels in mid-to-late June and plant in batches every week; one month before the sugarcane blooms, phimosis the female parent to promote rooting; select parents with the same flowering period for hybridization.

[0052] 2. Hybrid seed treatment: After hybridization, the hybrid seeds are treated and placed in a cold storage for after-ripening. The temperature of the cold storage is controlled at 2°C and the after-ripening time is 4 days. After the after-ripening is completed, soak them in 45°C warm water for 2 days, and change the water every 12 hours. Before sowing, soak the seeds in a mixed reagent of 3 mg / L methyl salicylate, 8 mg / L tebuconazole, and 2 mg / L 2,4-dichlorophenoxyacetic acid for 2 days, then remove them and drain them to obtain the treated hybrid seeds.

[0053] 3. Seedling sowing: In March, the seedling medium is placed in the seedling box, and then the hybrid seeds are evenly sown on the seedling box for sowing. After the seedlings grow 4 true leaves, they are transplanted; the preparation method of the seedling medium is: select nutrient-rich soil, crush and sieve it, and mix it according to the mass ratio of soil: organic matter: fine sand = 7:2:1, and then sterilize it in a disinfection cabinet at 120℃ for 2h.

[0054] 4. Hybrid nursery screening: Transplant the transplanted seedlings to the field in May and select them at the end of the year or the beginning of the next year when the sugarcane is mature. Select plants with excellent performance based on the number of effective stems, hammer hardness, disease resistance, and sugar content.

[0055] Example 4

[0056] A method for efficient breeding using wild germplasm, comprising the following steps:

[0057] Hybrid A was obtained by crossing Yuetang 93-159 as the female parent and GXAS07-6-1, which has the bloodline of Imperata scabra and Scutellaria baicalensis, as the male parent; hybrid B was obtained by crossing Guitang 05-164 as the female parent with hybrid A; hybrid C was obtained by crossing Guitang 29 as the female parent with hybrid B.

[0058] 1. Parent treatment: Plant the male parent GXAS07-6-1 in barrels in mid-to-late June and plant in batches every other week; one month before the sugarcane blooms, phimosis the female parent to promote rooting; regulate the flowering period from mid-July to mid-September, and select parents with the same flowering period for hybridization.

[0059] The method for regulating the flowering period comprises the following steps:

[0060] During the nighttime illumination stage, the male parent was illuminated at night to delay the flowering period to coincide with the flowering period of the female parent. From mid-July to mid-September, the male parent was illuminated with a light source after sunset every day. The light intensity was 20 Lx for 50 minutes, and the treatment lasted for 58 days.

[0061] In the night-light-cut stage, the male parent was treated with night-light-cut treatment starting in mid-September. Light was applied from 0:00 to 4:00 a.m. every day. The light intensity was controlled at 120 Lx from 0:00 to 2:00 a.m. and 65 Lx from 2:00 to 4:00 a.m. The temperature was controlled at 29°C and the treatment lasted for 20 days.

[0062] During the light reduction treatment stage, light reduction treatment was carried out after the night light treatment. The lighting time was reduced by 2 minutes every day during 0:00-2:00 in the morning and 2:00-4:00 in the morning. The light intensity was controlled at 90Lx during 0:00-2:00 in the morning and 45Lx during 2:00-4:00 in the morning. The treatment continued for 12 days.

[0063] 2. Hybrid seed treatment: After hybridization, the hybrid seeds are treated and placed in a cold storage for after-ripening. The temperature of the cold storage is controlled at 2°C and the after-ripening time is 4 days. After the after-ripening is completed, soak them in 45°C warm water for 2 days, and change the water every 12 hours. Before sowing, soak the seeds in a mixed reagent of 3 mg / L methyl salicylate, 8 mg / L tebuconazole, and 2 mg / L 2,4-dichlorophenoxyacetic acid for 2 days, then remove them and drain them to obtain the treated hybrid seeds.

[0064] 3. Seedling sowing: In March, the seedling medium is placed in the seedling box, and then the hybrid seeds are evenly sown on the seedling box for sowing. After the seedlings grow 4 true leaves, they are transplanted; the preparation method of the seedling medium is: select nutrient-rich soil, crush and sieve it, and mix it according to the mass ratio of soil: organic matter: fine sand = 7:2:1, and then sterilize it in a disinfection cabinet at 120℃ for 2h.

[0065] 4. Hybrid nursery screening: Transplant the transplanted seedlings to the field in May and select them at the end of the year or the beginning of the next year when the sugarcane is mature. Select plants with excellent performance based on the number of effective stems, hammer hardness, disease resistance, and sugar content.

[0066] Example 5

[0067] A method for efficient breeding using wild germplasm, comprising the following steps:

[0068] Hybrid A was obtained by crossing Yuetang 93-159 as the female parent and GXAS07-6-1, which has the bloodline of Imperata scabra and Scutellaria baicalensis, as the male parent; hybrid B was obtained by crossing Guitang 05-164 as the female parent with hybrid A; hybrid C was obtained by crossing Guitang 29 as the female parent with hybrid B.

[0069] 1. Parent treatment: Plant the male parent GXAS07-6-1 in barrels in mid-to-late June and plant in batches every other week; one month before the sugarcane blooms, phimosis the female parent to promote rooting; regulate the flowering period from mid-July to mid-September, and select parents with the same flowering period for hybridization.

[0070] The method for regulating the flowering period comprises the following steps:

[0071] During the nighttime illumination stage, the male parent was illuminated at night to delay the flowering period to coincide with the flowering period of the female parent. From mid-July to mid-September, the male parent was illuminated with a light source after sunset every day. The light intensity was 20 Lx for 50 minutes, and the treatment lasted for 58 days.

[0072] In the night-light-cut stage, the male parent was treated with night-light-cut treatment starting in mid-September. Light was applied from 0:00 to 4:00 a.m. every day. The light intensity was controlled at 120 Lx from 0:00 to 2:00 a.m. and 65 Lx from 2:00 to 4:00 a.m. The temperature was controlled at 29°C and the treatment lasted for 20 days.

[0073] During the light reduction treatment stage, light reduction treatment was carried out after the night light treatment. The lighting time was reduced by 2 minutes every day during 0:00-2:00 in the morning and 2:00-4:00 in the morning. The light intensity was controlled at 90Lx during 0:00-2:00 in the morning and 45Lx during 2:00-4:00 in the morning. The treatment continued for 12 days.

[0074] For water stress, the male parent was soaked in water three times in late August, late October and late November, with an interval of 2.5 days between each soaking treatment. The soaking treatment was carried out using automatic drip irrigation with a drip irrigation time of 3.5 hours.

[0075] 2. Hybrid seed treatment: After hybridization, the hybrid seeds are treated and placed in a cold storage for after-ripening. The temperature of the cold storage is controlled at 2°C and the after-ripening time is 4 days. After the after-ripening is completed, soak them in 45°C warm water for 2 days, and change the water every 12 hours. Before sowing, soak the seeds in a mixed reagent of 3 mg / L methyl salicylate, 8 mg / L tebuconazole, and 2 mg / L 2,4-dichlorophenoxyacetic acid for 2 days, then remove them and drain them to obtain the treated hybrid seeds.

[0076] 3. Seedling sowing: In March, the seedling medium is placed in the seedling box, and then the hybrid seeds are evenly sown on the seedling box for sowing. After the seedlings grow 4 true leaves, they are transplanted; the preparation method of the seedling medium is: select nutrient-rich soil, crush and sieve it, and mix it according to the mass ratio of soil: organic matter: fine sand = 7:2:1, and then sterilize it in a disinfection cabinet at 120℃ for 2h.

[0077] 4. Hybrid nursery screening: Transplant the transplanted seedlings to the field in May and select them at the end of the year or the beginning of the next year when the sugarcane is mature. Select plants with excellent performance based on the number of effective stems, hammer hardness, disease resistance, and sugar content.

[0078] Control example 1: The sugarcane variety used in this control example is New Taiwan Sugar No. 22.

[0079] Control example 2: The sugarcane variety in this control example is Guitang 42.

[0080] The experimental site was located in Long'an County, Guangxi Province. Plants were planted in ridged plots with a spacing of 20 cm and a row spacing of 50 cm. Each experimental field covered an area of ​​1 mu. Hybrid A obtained in Example 1 was named ASF108-2-28, and hybrid B was named ASBC112-A6-3.

[0081] The difficulty of flowering is judged based on the flowering rate of the plant in the following year. Plants with a flowering rate ≤ 10% are difficult to bloom, and the rest are easy to bloom.

[0082] Pollen viability was determined using in vitro germination and staining methods, using iodine-potassium iodide (I2-KI) staining. Pollen grains contain starch, which turns blue when exposed to iodine. Vitality was determined by the depth of the color. Three active inflorescences were selected from spikes that were 1 / 4 to 1 / 3 open. Two unopened spikelets adjacent to opened spikelets were selected from each spike. The yellow anthers within the spikelets were carefully squeezed out with tweezers and placed on a glass slide. One drop of 1% I2-KI solution was then added, and the anthers were gently crushed. The anthers were covered with a coverslip and observed under a microscope (10×4 magnification). Pollen grains that were spherical and stained bluish-brown were considered viable, while those that were triangular or shrunken and unstained or very lightly stained were considered immature or underdeveloped, indicating inactivity. Three fields of view were observed consecutively to assess pollen abundance and staining rate. The hundredth digit is represented by 1 when the pollen amount occupies less than 50% of the total visual field area, and the hundredth digit is represented by 2 when it exceeds 50%. The tens and units digits represent the pollen staining rate.

[0083] Tables 1 and 2 below show the sugarcane characteristics of the female and male parents.

[0084] Table 1 Characteristics of female sugarcane

[0085]

[0086] Table 2 Sugarcane characteristics of male parent

[0087] Male parent Flowering period Pollen Vitality Difficulty of flowering Features GXAS07-6-1 Early November 150 easy Good pollen fertility and resistance <![CDATA[ASF108-2-28]]> Late November to early December 280 easy Tall plants with more effective stems <![CDATA[ASBC112-A6-3]]> Late November 250 easy High sugar content, strong perennial rooting

[0088] Hybrid C obtained in Example 1 was named ASBC215-114. Comparisons of ASBC215-114 with New Taiwan Sugar 22 and Guitang 42 revealed that ASBC215-114 surpassed the control varieties New Taiwan Sugar 22 and Guitang 42 in sugar content, brix, effective stems, and smut resistance, as shown in Table 3.

[0089] Table 3 Agronomic traits of ASBC215-114, New Taiwan Sugar 22, and Guitang 42

[0090]

[0091] The germination rates of Examples 1-5 and the flowering period of the male parent hybrid A were tested, as shown in Table 4 below.

[0092] Table 4 Germination rate of Examples 1-5 and flowering period of male parent hybrid A

[0093]

[0094]

[0095] As can be seen from Table 4, the hybrid seed treatment method of the present invention can improve the germination rate, light regulation can delay the flowering period, and water stress can prolong the flowering period and improve the accuracy of the delayed flowering period, so that the flowering periods of the male and female parents coincide, thereby eliminating the need for artificial pollen collection and refrigeration in advance, reducing the decrease in pollen viability, and thus improving the breeding efficiency of wild germplasm.

[0096] In summary, the present invention provides a method for efficient breeding using wild germplasm, wherein a low-fertility sugarcane variety with poor pollen shedding, low pollen development rate, and high sugar content is selected, and a high-fertility wild sugarcane with high adaptability, disease resistance, cold resistance, drought resistance, and low sugar content is selected as parents for hybrid breeding. The high fertility and high resistance of the wild sugarcane make up for the insufficient breeding ability of the low-fertility sugarcane variety, and the wild germplasm is used to improve breeding efficiency. The hybrid variety obtained by the present invention has high sugar content, many effective stems, good growth vigor, strong resistance to smut, and obvious super-parent advantage.

[0097] The present invention can accurately regulate the flowering period of wild species through light treatment in the night light stage, the night light-off stage, and the light reduction treatment stage, and postpone the flowering period of the wild species to coincide with the cultivated species. The night light stage simulates the photoperiod changes in the natural environment. The night light-off stage and the light reduction treatment stage regulate hormone and metabolic synthesis, delay flower bud differentiation, and delay flowering. Mild water stress can simulate the alternating changes of drought and moisture in the natural environment by regulating soil moisture conditions, promote the physiological response of wild species, prolong the flowering period, and improve the accuracy and stability of flowering period regulation, thereby postponing the flowering period of the male parent GXAS07-6-1 from early November to early December to mid-January.

[0098] In the seed treatment step of the present invention, the seeds are first placed in a cold storage for low-temperature treatment at 1-3°C for after-ripening, and then soaked in warm water at 40-50°C after the seeds are taken to promote physiological maturation of the seeds. The warm water soaking can soften the seed coat and improve the water absorption and germination ability of the seeds. Before sowing, the seeds are soaked in a mixed reagent of 2-4 mg / L of methyl salicylate, 5-10 mg / L of tebuconazole, and 1-3 mg / L of 2,4-dichlorophenoxyacetic acid. The soaking in the mixed reagent can further improve the disease resistance and vitality of the seeds, and ultimately ensure that the seeds can quickly germinate and grow healthily after sowing, thereby improving the germination rate of the seeds, and can increase the germination rate of hybrid seeds to more than 90%.

[0099] The foregoing descriptions of specific exemplary embodiments of the present invention are for purposes of illustration and description. These descriptions are not intended to limit the invention to the precise forms disclosed, and it is apparent that many variations and modifications are possible in light of the foregoing teachings. The exemplary embodiments have been selected and described for the purpose of explaining the specific principles of the invention and their practical application, thereby enabling those skilled in the art to realize and utilize a variety of exemplary embodiments of the invention and various options and modifications. The scope of the invention is intended to be defined by the claims and their equivalents.

Claims

1. A method for efficient breeding using wild germplasm, characterized in that: The steps include: Hybrid A was obtained by crossing Yuetang 93-159 as the female parent and GXAS07-6-1, which has the bloodline of Imperata serrata and Scutellaria serrata, as the male parent. Hybrid B was obtained by crossing Hybrid A with Guitang 05-164 as the female parent; Hybrid C was obtained by hybridizing Guitang 29 with hybrid B.

2. The method for efficient breeding using wild germplasm according to claim 1, characterized in that: The breeding method specifically comprises the following steps: Parent selection: First, Yuetang 93-159 was used as the female parent, and GXAS07-6-1, which has the bloodline of Imperata serrata and Scutellaria baicalensis, was used as the male parent; then Guitang 05-164 and Guitang No. 29 were selected as recurrent parents; Parent treatment: Plant the male parent GXAS07-6-1 in barrels in mid-to-late June, and plant in batches every other week. One month before the sugarcane blooms, phimosis the female parent to promote rooting. Select parents with the same flowering period for hybridization. Hybrid seed treatment: After hybridization, the hybrid seeds are subjected to after-ripening treatment to obtain treated hybrid seeds; Seedling sowing: In March or April, place the seedling medium in the seedling box, then evenly sow the hybrid seeds on the seedling box for sowing. After the seedlings grow 3-5 true leaves, they are transplanted. Hybrid nursery screening: Transplant the transplanted seedlings to the field in May-June, and select them at the end of the year or the beginning of the next year when the sugarcane is mature. Select plants with excellent performance based on the number of effective stems, hammer hardness, disease resistance, and sugar content.

3. The method for efficient breeding using wild germplasm according to claim 2, characterized in that: In the seedling sowing step, the seedling medium is prepared by crushing and sieving nutrient-rich soil, mixing the soil: organic matter: fine sand at a mass ratio of 7:2:1, and then sterilizing the mixture at 120°C for 2 hours in a disinfection cabinet.

4. The method for efficient breeding using wild germplasm according to claim 2, characterized in that: The parent treatment step further includes regulating the flowering period from mid-July to mid-September, and the method for regulating the flowering period includes the following steps: S1, night light stage, the male parent was exposed to night light treatment, from mid-July to mid-September, with a light source for 40-60 minutes after sunset every day, and the treatment lasted for 55-60 days; S2, the night light-off stage, the male parent began to be treated with night light from mid-September, and was illuminated with a light source from 0:00 to 4:00 every morning. The light intensity was controlled at 100-150Lx from 0:00 to 2:00 in the morning, and 50-80Lx from 2:00 to 4:00 in the morning, and the treatment lasted for 15-25 days; S3, light reduction treatment stage: light reduction treatment is carried out after the night light treatment is completed. The lighting time during 0:00-2:00 in the morning and 2:00-4:00 in the morning is reduced by 2 minutes every day. The light intensity during 0:00-2:00 in the morning is controlled to 80-100Lx, and the light intensity during 2:00-4:00 in the morning is controlled to 30-60Lx. The treatment continues for 10-15 days.

5. The method for efficient breeding using wild germplasm according to claim 4, characterized in that: In step S1, the light intensity after sunset is 10-30 Lx.

6. The method for efficient breeding using wild germplasm according to claim 4, characterized in that: The step S2 also includes controlling the temperature of the nighttime illumination treatment stage to be 28-30° C. and the remaining illumination treatment stages to be at atmospheric temperature.

7. The method for efficient breeding using wild germplasm according to claim 4, characterized in that: The method for regulating the flowering period also includes water stress, wherein the male parent is soaked in water three times in late August, late October and late November, with an interval of 2-3 days between each soaking treatment. The soaking treatment adopts automatic drip irrigation, and the drip irrigation time is 3-4 hours.

8. The method for efficient breeding using wild germplasm according to claim 1, characterized in that: The hybrid seed processing step specifically comprises: Place the seeds in a cold storage for ripening. The temperature of the cold storage is controlled at 1-3℃. The ripening time is 3-5d. After ripening, soak them in 40-50℃ warm water for 2-3d. Change the water every 12h. Before sowing, soak the seeds in a mixed reagent of 2-4mg / L methyl salicylate, 5-10mg / L tebuconazole, and 1-3mg / L 2,4-dichlorophenoxyacetic acid for 1-2d, then remove and drain.

9. The method for efficient breeding using wild germplasm according to claim 8, characterized in that: The ratio of the mixed reagent to seeds is 1L:15-20kg.

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