Winter wheat in-situ one-year multi-generation breeding method

Abstract

This invention discloses a rapid in-situ multi-generation breeding method for winter wheat. The method involves multi-generation breeding in a glass greenhouse and artificial climate chamber, while simultaneously planting multiple generations in the field. Through continuous screening and comparative analysis of seeds from different generations, propagated in different environments, and treated with different fertilizers and water, stable F5 seeds can be obtained over a period of more than a year. This allows for the selection of initially superior combinations, avoiding material loss due to inconsistencies between artificial and field climates, and rapidly obtaining excellent strains.

Description

Technical Field

[0001] This invention relates to the field of wheat breeding, specifically to a rapid in-situ multi-generation breeding method for winter wheat. Background Technology

[0002] Conventional hybridization breeding involves creating genetic variation through inter-varietal hybridization, followed by selection of offspring that have undergone multiple generations of self-pollination, resulting in homozygous offspring with stable traits, to breed new varieties with specificity, uniformity, and stability. During the self-pollination process, the number of generations directly affects the homozygous proportion of offspring. Taking a pair of independently inherited genes as an example, after five consecutive generations of self-pollination from F1 onwards, the proportion of homozygous individuals can reach as high as 96.875%. For winter wheat, at least 10-12 generations are required from parental hybridization to new variety approval, making the winter wheat breeding process quite lengthy. With increasing population, decreasing arable land, and rising demands for quality of life, higher requirements are being placed on wheat breeding efficiency. Shortening the winter wheat breeding cycle and improving breeding efficiency have become major trends in the advancement of winter wheat breeding technology.

[0003] Researchers in winter wheat breeding have explored various methods to accelerate the generation of wheat. They have developed methods to accelerate generational breeding in both in-situ and off-site conditions, fully utilizing different ecological conditions. In winter greenhouses or under off-season conditions, based on the different needs of wheat at different stages, they control temperature, provide special light and water, and break through seasonal and location limitations to accelerate the generation of winter wheat. In particular, for the selection of individual plants in the F2 generation of winter wheat, they adopt the "three emphases, four exclusions, and five retentions" selection criteria. The "three emphases" are: first, emphasizing plant height (i.e., the selected individual plant should be shorter than the control and parent plants planted nearby); second, emphasizing disease resistance (especially resistance to powdery mildew, which should be better than the parent and control); and third, emphasizing yield structure (mainly the number of ears per plant and the number of grains per ear). The "four exclusions" are: first, excluding those with rapid jointing (poor frost resistance); second, excluding those with early heading (preferring spring characteristics); third, excluding those with tall stalks (poor lodging resistance); and fourth, excluding those with full grains (strong spring characteristics). The "five retention criteria" are: 1) retention of plants with robust jointing; 2) retention of plants with late heading; 3) retention of plants with shorter stature; 4) retention of plants with a high number of ears per plant; and 5) retention of plants with underdeveloped grains. This achieves two generations per year. Some scholars have also used embryo culture and other techniques to achieve multiple generations of breeding per year. However, these techniques still have significant shortcomings, such as the challenges of long distances, high labor and time consumption, and inconvenient management in off-site accelerated generation breeding. Embryo culture technology also suffers from high skill requirements for operators and expensive reagents. Therefore, developing simpler and more efficient methods for in-situ accelerated generation of wheat is crucial for the rapid breeding of superior new wheat varieties. Summary of the Invention

[0004] To address the above-mentioned technical shortcomings, this invention provides a rapid in-situ breeding method for winter wheat with multiple generations in one year.

[0005] This invention is achieved through the following technical solution:

[0006] This invention creates a rapid breeding method for winter wheat that involves multiple generations in situ over a year, which can accelerate the breeding process of winter wheat and promote the innovation of wheat breeding technology in the northern winter wheat region.

[0007] Table 1 Temperature requirements of wheat at different growth stages

[0008] During the reproductive period highest temperature minimum temperature Suitable temperature budding stage 32-37℃ 2-4℃ 15-25℃ Seedling stage 32-35℃ 3-5℃ 15-18℃ Tillering stage 23-28℃ 0-3℃ 10-17℃ Overwintering period 8-10℃ -4--8℃ 3-5℃ Propagation period 30-32℃ 8-10℃ 12-16℃ Heading stage 32-35℃ 9-10℃ 13-20℃ Flowering period 30-32℃ 9-11℃ 18-24℃ Grouting to maturity stage 32-35℃ 10-12℃ 18-22℃

[0009] Parent selection

[0010] By selecting backbone parents and intermediate materials with different superior traits, we can become familiar with the advantages of the parents and utilize complementary parental combinations.

[0011] Hybrids

[0012] In the first year, the selected parent lines and intermediate materials with superior traits were prepared and sown in the field at the end of September. In early December of the first year, the wheat seedlings were dug up and transplanted into a breeding greenhouse. Before transplanting, the following preparations were necessary: ​​meticulous land preparation and application of 600 kg / hm² of compound fertilizer as basal fertilizer. 2 Prepare raised beds on level ground, 10cm high and 1.0-1.5m wide. Then mark rows with a spacing of 25-30cm. Use a hoe to dig furrows along the marked rows. The spacing between transplanting plants can be determined based on the number of tillers, generally 8-15cm. Ensure quality transplanting by covering the plants with appropriate amounts of soil. After transplanting, apply an appropriate amount of urea (40kg / hm²). 2 (Approximately 1000-1200 mm) timely sprinkler irrigation, watering once every 7 days after transplanting. After one week of seedling establishment, immediately activate the heating system to raise the temperature to the suitable level for each growth stage of wheat (see Table 1), supplementing with light for up to 22 hours daily. Wheat growth requires a mixed spectrum of red light with a wavelength of 660 nm, blue light with a wavelength of approximately 460 nm, and a small amount of green light. The specific spectral ratio needs to be adjusted and optimized based on the wheat's growth stage, variety, and environmental factors to achieve the best growth effect and yield. Red light can increase wheat plant height, make leaves wider and thicker, and stems stronger; a suitable proportion of red light can improve wheat growth rate and quality. Blue light can promote chlorophyll synthesis in wheat, increasing photosynthetic efficiency and yield. Simultaneously, blue light can also affect the plant morphology and flowering period of wheat, making the wheat more robust and the flowering period more stable. Green light helps wheat plants with respiration, maintaining vitality and metabolic balance.

[0013] Artificial pollination is carried out in the early flowering stage. The emasculated female parent is bagged, and the date of emasculation is written on the bag. Within the male parent population, select robust male ears with one or two small florets already shedding pollen from the upper middle part of the ear. Cut off the tip of the glumes along with the awns from bottom to top, shorten the ear, and insert it into the soil to await pollen shedding. After pollen shedding, cut off the top of the paper bag covering the emasculated female ear. Gently pull out the male ear inserted in the soil, open the paper bag with one hand, and carefully place the male ear, cut side down, into the paper bag. Rotate and shake it several times to allow pollen to fall onto the stigma of the pistil, completing artificial pollination. After pollination, fold and clamp the cut end of the paper bag, write the names of the male and female parents and the date of hybridization on a label, and hang it up. Harvest 15 days after flowering and pollination at the end of January of the following year. Pull the entire plant upside down and hang it in a greenhouse for another 3 days. The grains are dried and threshed, and then tested indoors.

[0014] One ride

[0015] The F1 seeds harvested at the end of January of the following year were soaked in 1.5% hydrogen peroxide for 24 hours, rinsed, and then dried until the surface was free of moisture. Generally, winter and semi-winter varieties can be directly sown in the field, or the seeds can be treated at a low temperature of 1-3℃ for more than 7 days before sowing in furrows in the field. The sowing site is a plot reserved for autumn sowing before the previous year. The plot should be prepared before winter, watered to retain moisture, and covered with greenhouse film to retain moisture and warmth during winter. Spring sowing should be done as early as possible, covered with mulch film after sowing, and removed after emergence. Later management is the same as in the field. In early March of the following year, a portion of the F1 plants were dug up and transplanted into an artificial climate chamber. The temperature of the artificial climate chamber was adjusted according to the optimal temperature for wheat at each stage, and sufficient light was provided. Watering was applied during droughts. The traits of each combination in the field and artificial climate chamber were recorded, and combinations with insufficient heterosis were eliminated based on heterosis. F2 seeds from materials grown in the artificial climate chamber were harvested 15 days after flowering in mid-April of the following year. F2 seeds from field-grown materials were harvested in early June of the following year, dried, threshed, and tested indoors. Based on the test results, further selection and culling were conducted. A portion of the seeds were selected for further generations in the artificial climate chamber, while the remaining seeds were prepared for autumn sowing in early October. The seeds were treated differently, one from the artificial climate chamber and the other from the field, because the traits of wheat grown in the artificial climate chamber might differ from those in the field. The two batches, grown in different environments, were finally planted together in the field. This served two purposes: firstly, to check in the field to ensure no superior traits were missed or incorrect selections were made; and secondly, to observe the performance of each generation for a comprehensive evaluation.

[0016] Second addition

[0017] F2(R) seeds harvested in mid-April of the following year from an artificial climate chamber, and F2(D) seeds matured in the field in early June of the following year, were promptly harvested and thoroughly dried. They were then treated with hydrogen peroxide in batches to break dormancy. Seeds were soaked in 1.5% hydrogen peroxide for 24 hours, rinsed with clean water, and sown in seed trays, with several rows of F2(R) and several rows of F2(D), and several plants per row. The substrate in the seed trays consisted of nutrient soil, field soil, and vermiculite in a 1:1:1 ratio. The seeds were initially cultivated in an artificial climate chamber until they had two leaves and a central bud, then transferred to a low-temperature, high-light incubator at 3–5℃. In the low-temperature, high-light incubator, water was applied during droughts and sprayed with water every 3 days. After more than 35 days of low-temperature vernalization treatment, vernalization was completed by mid-May and mid-July of the following year (slightly later in the field, but subsequent steps were similar). In the artificial climate chamber, the temperature was adjusted according to the optimal temperature for each wheat stage, and sufficient light was provided. Watering was applied during droughts. It is important to note that the time for generation in summer is limited, so it should be done as early as possible. Research shows that wheat seeds can germinate normally 15 days after flowering, therefore, harvesting can be done early, before the previous generation's grains mature. Seeds should be dried promptly, dormancy broken, and vernalization treatment carried out in a timely manner. During the growing season, appropriate fertilizer and water management should be implemented according to the seedling condition, preferably by spraying. Attention should be paid to the prevention and control of pests and diseases, and the traits of each combination in different batches should be recorded. F2(R) single plants should be harvested at the end of June of the following year to obtain F3(R) grains; F2(D) single plants should be harvested at the end of August to obtain F3(D) grains. Combinations with superior trait performance should be pulled up whole (recording plant height, tillers, and number of ears) and hung upside down in an artificial climate chamber for three days for grain harvesting. The grains should be dried and threshed individually and tested indoors. Based on the test results, hybrid combinations should be eliminated or selected.

[0018] Three times

[0019] After the F3 grains were harvested at the end of June and August of the following year, they were divided into two parts. One part was sown in the field in early October (see next step); the other part underwent three generations in an artificial climate chamber. The F3 grains from the three generations were dried in time and treated with hydrogen peroxide to break dormancy. After rinsing, they were sown in seed trays and cultivated in the artificial climate chamber. When the wheat reached the two-leaf stage, it was placed in a low-temperature light incubator at 3-5℃ for a vernalization treatment of more than 35 days. In mid-August and mid-October, the artificial climate chamber was equipped with heating and supplemental lighting facilities to maintain suitable temperatures for each growth stage of the wheat. Watering was carried out during droughts, and attention was paid to the prevention and control of diseases and pests. The traits of each combination were recorded, including resistance, disease and pests, tillering, etc. F4(R) and F4(D) grains of combinations with excellent traits were harvested 15 days after flowering and pollination at the end of September and November, respectively. The whole plant was pulled up and hung upside down in an artificial climate chamber to dry and thresh. The seeds were then tested indoors, and combinations with excellent yield and superior traits were selected based on the test results.

[0020] Autumn sowing in Datian in early October of the next year

[0021] The retained F2 and F3 generation seeds, F4(R) seeds obtained from the generation at the end of September, and parental materials were all sown in the field in early October for subsequent trait surveys and verification to avoid omissions. For the F2 generation, a small-population, multi-type individual selection method was used for F2 single-plant breeding. The key points were: a small planting population for each hybrid combination (115–680 seeds), a variety of selected single-plant types, and superior traits. F2 sowing methods included row sowing and spot sowing. Row sowing involved 2–3 rows, with a full harvest for yield measurement; spot sowing resulted in a larger seed spacing (10–15 cm), better individual growth and development, and higher seed yield. For the F3 generation, a multi-treatment, multi-environment identification and screening method was used. The key points were: using multiple treatments (different seeding rates, different sowing methods, and different replicates) and various environmental conditions, including irrigated and dry land, to cultivate, identify, and screen F3 lines. The specific method is to divide the F3 seeds into 3-4 portions. Two portions (replicates) are planted in fertile, water-rich areas, with one portion sown by spot sowing at 100 seeds per row for 2 rows, and the other portion sown in rows at 150 seeds per row for 3 rows. One to two portions are planted in dry, fertile areas, all in rows at 150 seeds per row for 2-3 rows, with a row length of 2.2 meters. Controls are set up in both water-rich and dry areas for yield comparison. (If the seed production from the second generation is insufficient, the seeds from the two generations are replicated; however, due to different planting environments, the segregation may differ, and different strain groups should be compared and identified separately). The F4 generation is sown at different rates, 50 seeds and 100 seeds, using both spot and row sowing methods, and is sown separately in water-rich and dry areas.

[0022] four times

[0023] F4(D) seeds harvested at the end of November of the following year in an artificial climate chamber were soaked in 1.5% hydrogen peroxide for 24 hours, rinsed, and dried until the surface was dry before direct sowing in the field (covered with plastic film). Alternatively, the seeds could be treated at a low temperature of 1-3℃ for more than 7 days when germination began before sowing in furrows in the field (covered with plastic film). The sowing plots were reserved for autumn sowing the previous year and connected to the planting plots of materials for each generation sown in early October of the following year, facilitating later trait surveys. The plots should be treated to retain moisture and maintain temperature. When sowing the F4 generation, different sowing rates of 50 and 100 seeds were used for spot sowing and row sowing, and sowing was carried out separately in paddy fields and dry fields. Seeds of F4 (mixed-line seeds) from lines that performed well in the F3 generation were placed in both high-fertility and dry-fertility fields for multi-repeated plot trials, i.e., a comparative yield test of mixed-line seeds in paddy and dry areas. Spring sowing should be done as early as possible, and the seeds should be covered with plastic film after sowing. The film should be removed after emergence, and later management is the same as in the field. Using drones equipped with multispectral cameras, trait data were collected and field-verified. Combinations of various traits from each generation were extracted and labeled, and combinations with superior traits were selected. Comparisons across generations allowed for the checking of any missed superior combinations. It was ensured that seeds from each generation were identified in the field to avoid material loss due to inconsistencies between artificial and real-field climates. Traits for each combination, such as yield and disease resistance, were recorded. Stable F5 seeds were collected in early June of the third year, dried, threshed, and tested indoors. Based on the F4 generation's yield, resistance, maturity, adaptability, and other traits, lines with superior and stable expression were selected. F4 plot comparisons were conducted with two replicates, eliminating combinations with poor trait performance. The collected F5 seeds were comprehensively evaluated, and combinations with exceptionally outstanding performance were used in various trials.

[0024] Applying spectral and remote sensing technologies to wheat plant trait detection significantly reduces labor costs, decreases the frequency of personnel entering and exiting wheat breeding bases, avoids the introduction of infectious diseases by personnel carrying pathogens, and ensures healthy wheat growth and development. In the breeding of new wheat varieties, applying remote sensing technology to pest and disease control enables timely detection and treatment of pests and diseases. Image processing and automated identification technologies can accurately identify the severity of common pests and diseases (eliminating disease-intolerant combinations and lines in advance), achieving an identification rate of over 80% compared to traditional methods. The effective combination of drone technology and unmanned remote sensing technology allows for better acquisition of growth traits in new wheat varieties, such as lodging status, leaf index, yield indicators, and canopy temperature. This provides valuable information for optimizing and improving wheat breeding work, ensuring its efficient implementation.

[0025] The beneficial effects of this invention are as follows: This invention provides a rapid, in-situ multi-generation breeding method for winter wheat, tailored to the growth characteristics of winter wheat in northern regions. It comprehensively utilizes the local environment of the winter wheat breeding area, along with suitable conditions for winter wheat growth and development, such as glass greenhouses and artificial climate chambers. Combined with artificial dormancy breaking and vernalization treatments, this method completes multiple generations of seed propagation within a single year through local planting. This invention rationally adjusts the wheat development period, uniformly planting materials from multiple generations in the same field, facilitating trait comparison and screening for superior combinations and variations. This invention ensures that seeds from each generation are identified in the field, avoiding material loss due to inconsistencies between artificial and field climates. The method provided by this invention is not only simple and rapid in terms of generation addition, but also facilitates trait investigation and comparison during generation addition, which is beneficial for screening superior combinations. Attached Figure Description

[0026] Figure 1 A schematic diagram of the rapid breeding process for winter wheat with multiple generations in situ over one year;

[0027] Figure 2 Photograph of Ota for strain SH5258. Detailed Implementation

[0028] Example: Variety SH5258 was bred in-situ for multiple generations over one year.

[0029] Breeding goals and parent selection

[0030] The breeding objectives were high yield and early maturity. Shannong 28 was selected as the female parent and Taimai 198 as the male parent. The female parent's advantages include: extremely high yield potential, strong resistance to adverse conditions, medium-early maturity, and good adaptability. It is particularly tolerant of high temperatures in the later stages, has rapid grain filling, good yellowing, excellent stem quality, good elasticity, and lodging resistance. It matures 1.7 days earlier than Jimai 22. Inoculation tests conducted by the Institute of Plant Protection, Chinese Academy of Agricultural Sciences, showed high resistance to powdery mildew and good disease resistance. The male parent's advantages include: good maturity appearance, high resistance to wheat leaf rust, moderate resistance to wheat scab, and yield performance exceeding that of the control variety Jimai 22 by over 5.0%.

[0031] Hybrids

[0032] In late September 2021, the selected male parent Taimai 198 and female parent Shannong 28, along with other parental lines, with superior traits, were prepared, dried promptly, and treated with hydrogen peroxide to break dormancy before being sown in the field. In early December, the wheat seedlings were dug up and transplanted to the breeding and generation-enhancing glass greenhouse of Zibo Hefeng Seed Industry Technology Co., Ltd. Watering was provided during droughts after transplanting. After a week of recovery, the heating system was immediately activated to raise the temperature to the suitable level for each growth stage of the wheat, and supplemental lighting was provided for 22 hours daily to help the wheat obtain more suitable light in the greenhouse, making its growth environment closer to natural conditions.

[0033] Artificial pollination should be carried out in the early flowering stage. The emasculated female parent should be bagged, and the date of emasculation should be recorded. During the peak flowering period, attention should be paid to disease and pest control. Within the male parent population, select healthy male ears with one or two small florets already shedding pollen from the upper middle part of the ear. Cut off the top of the glumes along with the awns one by one from bottom to top, shorten the ear, and insert it into the soil to await pollen shedding. After pollen shedding, cut off the top of the paper bag covering the emasculated female ear. Gently pull the male ear out of the soil, open the paper bag with one hand, and carefully place the male ear, cut side down, into the paper bag with the other. Rotate and shake it several times to allow pollen to fall onto the stigma of the pistil, completing artificial pollination. After pollination, fold and clamp the cut end of the paper bag, write the names of the male and female parents and the date of hybridization on a label, and hang it up. Harvesting took place 15 days after flowering and pollination at the end of January 2022. The entire plant was pulled up and hung upside down in a greenhouse, where it was kept warm for another 3 days. The seeds were then dried, threshed, and tested indoors.

[0034] One ride

[0035] Thirty-one seeds from combination W21(88)F1, harvested at the end of January 2022, were soaked in 1.5% hydrogen peroxide for 24 hours, rinsed, and dried until the surface was dry. When the seeds began to germinate, they were treated at a low temperature of 1-3℃ for more than 7 days before being sown in furrows in the field. The sowing plots had been prepared before winter, watered and stored for moisture, and covered with greenhouse film to retain moisture and heat during winter. After emergence, the film was removed, and the later management was the same as in the field. In early March 2022, 15 F1 plants were dug up and transplanted into an artificial climate chamber. The temperature of the artificial climate chamber was adjusted according to the optimal temperature for each stage of wheat growth (see Table 1), and sufficient light was provided. Water was applied during droughts. The traits of each combination in the field and artificial climate chamber were recorded, and some combinations with insignificant heterosis were eliminated based on heterosis. In the artificial climate chamber, 15 days after flowering in mid-April 2022, two F1 generation plants were harvested to obtain F2(R) seeds. In the field, four F1 generation plants were harvested by early June 2022 to obtain F2(D) seeds. The seeds were dried, threshed, and tested indoors. Based on the test results, superior combinations were then eliminated and selected.

[0036] Second addition

[0037] F2(R) grains harvested in mid-April 2022 in an artificial climate chamber, and F2(D) grains matured in early June, were promptly harvested and thoroughly dried. They were then treated with hydrogen peroxide in batches to break dormancy. Seeds were soaked in 1.5% hydrogen peroxide for 24 hours, rinsed with water, and sown in seed trays. F2(R) seeds were planted in 5 rows, and F2(D) seeds in 10 rows, with 5 plants per row. The substrate in the seed trays consisted of nutrient soil, field soil, and vermiculite in a 1:1:1 ratio. Initially, the seeds were cultivated in an artificial climate chamber. When the seedlings had two leaves and one bud, they were placed in a 3-5℃ low-temperature light incubator. In the low-temperature light incubator, water was sprayed every 3 days. After more than 35 days of low-temperature vernalization treatment, vernalization was completed in mid-May and mid-July 2022. The temperature in the artificial climate chamber was adjusted according to the optimal temperature for each wheat stage, and sufficient light was provided. Watering was applied during droughts. During the growth period, appropriate fertilizer and water management should be carried out according to the seedling condition, preferably by spraying, and attention should be paid to the prevention and control of diseases and pests. The traits of each combination in different batches were recorded. Fifteen days after flowering and pollination, the combination with excellent traits was pulled up whole (plant height, tillering, and number of ears were recorded) and hung upside down in an artificial climate chamber for three days for grain harvesting. The grains were dried and threshed on a single plant basis and tested indoors. Based on the test results, further selection and elimination were carried out. At the end of June 2022, 6 F2(R) single plants were harvested to obtain F3(R) grains, and at the end of August 2022, 13 F2(D) single plants were harvested to obtain F3(D) grains.

[0038] Three times

[0039] After the F3 grains were harvested at the end of June and August 2022, a portion was sown in the field in early October 2022. Another portion was promptly dried, treated with hydrogen peroxide to break dormancy, rinsed, and sown in seed trays, undergoing three generations in an artificial climate chamber. When the wheat reached the two-leaf stage, it was placed in a 3-5℃ low-temperature light incubator for vernalization treatment lasting more than 35 days. Vernalization was completed in mid-August and mid-October 2022. In the artificial climate chamber, heating and supplemental lighting facilities were activated to maintain suitable temperatures for each growth stage of the wheat. Watering was provided during droughts, and attention was paid to disease and pest control. The traits of each combination were recorded, including resistance, disease and pest performance, and tillering. Combinations exhibiting excellent traits were harvested 15 days after flowering and pollination at the end of September and November 2022. The entire plant was pulled upside down and hung upside down in the artificial climate chamber for drying and threshing. Seed testing was conducted indoors, and combinations with excellent yield and superior traits were selected based on the test results. At the end of September 2022, 53 superior F3(R) lines were selected to obtain F4(R) grains, and at the end of November, 67 superior F3(D) lines were selected to obtain F4(D) grains.

[0040] Autumn sowing in Datian in early October 2022

[0041] The retained F2, F3, and F4(R) generation seeds, along with parental materials, were sown in the field in early October 2022 for subsequent trait surveys and verification, ensuring no materials were missed. The F2 generation employed a small-population, multi-type individual selection method, specifically the F2 single-plant breeding method. Key points included: a smaller planting population for each hybrid combination (115–680 seeds), a greater variety of selected single plant types, and superior traits. F2 sowing methods included row sowing and spot sowing. Row sowing involved 2–3 rows for full-harvest yield measurement, while spot sowing resulted in larger seed spacing (10–15 cm), better individual growth and development, and higher seed yield. The F3 generation employed a multi-treatment, multi-environment identification and screening method. Key points included: using multiple treatments (different seeding rates, different sowing methods, and different replicates) and various environmental conditions, such as irrigated and dry land, to cultivate, identify, and screen F3 lines. If the amount of seed for generation is insufficient, the seeds can be added in batches as replicates. However, due to differences in planting environment, sowing time, and separation, it is necessary to carefully observe the characteristics of wheat at different stages and record and compare different strains in detail. Specifically, the seeds of selected individual plants from different batches of F2 are divided into 3-4 portions. Two portions (replicates) are planted in fertile, water-rich areas, with one portion sown by spot sowing at 100 seeds per row for 2 rows, and the other portion sown in rows at 150 seeds per row for 3 rows. One to two portions are planted in dry, fertile areas, all sown in rows at 150 seeds per row for 2-3 rows, with a row length of 2.2 meters. Controls are set up in both water-rich and dry areas to facilitate yield comparison.

[0042] four times

[0043] F4(D) seeds harvested at the end of November 2022 were soaked in 1.5% hydrogen peroxide for 24 hours, rinsed, and dried until the surface was dry. When the seeds began to germinate, they were treated at a low temperature of 1-3℃ for at least 7 days before being sown in furrows in the field, and covered with plastic film after sowing. The sowing plots were reserved for the autumn sowing in early October 2022 and were connected to the planting plots of various generations of materials sown in early October 2022 to facilitate later trait surveys. The plots were properly treated to retain moisture and maintain temperature. F4 generation seeds were also sown at different rates, 50 seeds and 100 seeds, using both spot sowing and row sowing methods, and were sown separately in irrigated and dry land. F4 (mixed-line seeds) obtained from F3 lines with excellent performance were simultaneously tested in both highly fertile and dry-fertile plots using multiple replicates, i.e., a comparative yield test of mixed-line seeds in irrigated and dry land. Using drones equipped with multispectral cameras, trait data were collected and validated in the field. Combinations of various traits from each generation were extracted and labeled. Superior trait combinations were selected, and comparisons were made across generations to identify any missed variations in superior combinations. This ensured that seeds from each generation were identified in the field, preventing material loss due to inconsistencies between artificial and real-field climates. Traits for each combination, such as yield and disease resistance, were recorded. Stable F5 grains were collected by early June 2023, dried, threshed, and tested indoors. Based on the F4 generation's yield, resistance, maturity, adaptability, and other traits, lines with superior and stable expression were selected. F4 plot comparisons were conducted with two replicates, eliminating combinations with poor trait performance. The collected F5 grains were comprehensively evaluated, and combinations with exceptionally high performance were used in various trials.

[0044] In the subsequent comprehensive evaluation of the line, it was found that the F5 generation line of the combination W21(66) with Shannong 28 as the female parent and Taimai 198 as the male parent performed extremely well and met the pre-set breeding objectives. The line was named SH5258 and retained, and recommended to participate in regional trials.

[0045] The above description is only a preferred embodiment of this patent. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of this patent, and these improvements and substitutions should also be considered within the scope of protection of this patent.

Claims

1. A rapid in-situ multi-generation breeding method for winter wheat, characterized in that, Includes the following steps: ST1 was used to obtain hybrid F1. In late September of the first year, male and female parents with excellent traits were selected and sown in the field. In early December, the wheat seedlings were dug up and transplanted into a breeding and generation glass greenhouse. F1 was harvested 15 days after flowering and pollination in late January of the second year. ST2, one generation; F1 was sown in the field, and in early March of the following year, a portion of the F1 plants were dug up and transplanted into an artificial climate chamber. F2(R) seeds were obtained 15 days after flowering in mid-April; F2(D) seeds were obtained from the field-grown materials by early June; the traits of each combination in the field and artificial climate chamber were recorded, and the combinations were tested after harvest. Combinations with insignificant heterosis were eliminated, and dominant combinations were selected. ST3, a second generation; F2(R) and F2(D) were treated with hydrogen peroxide and low-temperature vernalization in batches, with vernalization completed in mid-May and mid-July of the second year, respectively. F3(R) grains were obtained at the end of June and F3(D) grains at the end of August of the second year. Based on the combined traits and the test records, some combinations with insignificant heterosis were eliminated, and the dominant combinations were selected. ST4 was used for three generations; F3(R) and F3(D) were treated with hydrogen peroxide and low-temperature vernalization in batches, with vernalization completed in mid-August and mid-October of the second year, respectively. F4(R) grains were obtained at the end of September of the second year, and F4(D) grains were obtained at the end of November. Based on the combined traits and seed test records, some combinations with insignificant heterosis were eliminated, and dominant combinations were selected. In early October of the second year, autumn sowing was carried out in the field; the remaining F2 generation grains, F3 generation grains, F4(R) grains, and parental materials were all sown in the field in early October of the second year for phenotypic investigation. ST5, four generations; F4(D) grains harvested at the end of November of the second year were immediately sown in the field and connected with the autumn sowing plots in early October. Each generation was compared, and combinations with superior traits were selected; stable F5 grains were obtained in early June of the third year. The harvested F5 grains were comprehensively evaluated, and combinations with extremely excellent performance were used in various trials. In steps ST1-ST4, vernalization involves undergoing low-temperature vernalization treatment for more than 35 days in a low-temperature light incubator. In step ST4, the field is sown in early October of the second year. The F2 generation is selected by the small population multi-type individual selection method. The F3 generation is screened by the multi-treatment method and multi-environment identification screening method. The F4 generation is sown according to different sowing rates, spot sowing and row sowing, and sown in irrigated land and dry land respectively. In step ST4, the field is sown in early October of the second year. The F2 generation is selected by the small population multi-type individual selection method. The F2 sowing method is divided into row sowing and spot sowing. The row sowing is 2-3 rows, and one seed is sown every 10-15 cm. The yield is measured after the full harvest. In step ST4, the field autumn sowing is carried out in early October of the second year. The F3 generation is screened using a multi-treatment and multi-environment identification and screening method. The F3 line is cultivated, identified and screened under various environmental conditions, including different treatments, different sowing rates, different sowing methods and different replicates, in both irrigated and dry land. In step ST4, the second year's autumn sowing was carried out in early October. The F3 generation was screened using a multi-treatment, multi-environment identification and screening method. The F3 seeds were divided into 3-4 portions. Two portions were planted in fertile and irrigated land, one portion was sown by spot sowing, 100 seeds per row, 2 rows, and the other portion was sown by row sowing, 150 seeds per row, 3 rows. One to two portions were planted in dry and fertile land, all in row sowing, 150 seeds per row, 2-3 rows, with a row length of 2.2 meters. Controls were set up in both irrigated and dry land to facilitate yield comparison. In step ST4, the field autumn sowing is carried out in early October of the second year. The F4 generation is sown with different sowing rates, 50 seeds and 100 seeds respectively, by spot sowing and row sowing.

2. The breeding method according to claim 1, characterized in that: In steps ST1-ST4, wheat cultivation in greenhouses or artificial climate chambers requires supplemental lighting for up to 22 hours daily, with a spectrum consisting of red light at a wavelength of 660 nm, blue light at a wavelength of 460 nm, and a mixed spectrum doped with a small amount of green light.

3. The breeding method according to claim 1, characterized in that: In steps ST1-ST4, the harvested grains are selected from the whole plants of the combination with excellent trait performance. The plant height, tillering and number of ears are recorded. The plants are hung upside down in an artificial climate chamber for three days to harvest the grains. The grains are then dried and threshed on a single plant basis and tested indoors. The selection is carried out again based on the test results.

4. The breeding method according to claim 1, characterized in that: In step ST5, a multispectral camera mounted on a drone is used to collect traits and conduct field verification. Combinations of different traits from each generation are extracted and labeled, and combinations with superior traits are selected.

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