Machine-harvested cotton variety breeding method

Abstract

The invention discloses a machine-harvested cotton variety breeding method which comprises the following steps: step 1, in the first year, hybridizing a parent AY4 and Xinluzao No.12 in Xinjiang to obtain an F1 generation, and screening single plants; 2, in the second year, selfing the F1 generation in Xinjiang to obtain an F2 generation, and screening single plants; 3, in the third year, F2 generation screening single plants are planted in Xinjiang, south propagation is conducted in Hainan in the same year, and excellent single plants are screened; 4, in the fourth year, adding generations in Xinjiang to obtain F4-generation screening single plants; 5, from the fifth year to the ninth year, single plants are screened in Xinjiang every year for planting. According to the technical scheme, by taking adaptation to mechanical harvesting as a core target, specific parent and offspring single plant materials are screened through evaluation and selection of important upland cotton mechanical harvesting key characters such as a plant type structure, centralized maturation, high temperature resistance, easy tip sealing property, flower breaking property, branch boll carrying and node boll carrying, centralized defoliation and boll opening and the like; a good propagation system of a selfing mixed propagation method and a simultaneous storage separate propagation method is adopted, and cotton varieties with the characteristics that the plant morphology is suitable for mechanical operation, cotton boll distribution is reasonable, and the defoliation property is good are cultivated.

Description

Technical Field

[0001] This invention relates to the field of cotton breeding technology, specifically to a method for breeding machine-harvested cotton varieties. Background Technology

[0002] Xinjiang is a major cotton-producing area in my country. In 2024, the cotton planting area in Xinjiang was 245 million hectares. 5 hm 2 This accounts for 86.25% of the national total. Of this, the area of ​​machine-harvested cotton reached 2.2 × 10⁻⁶. 5 hm 2 The overall mechanization rate of cotton cultivation and harvesting in Xinjiang has reached over 97%, with machine harvesting exceeding 90%. Xinjiang possesses the most suitable natural environmental conditions for cotton cultivation, primarily characterized by its hot climate, abundant sunshine, scarce rainfall, dry air, and large diurnal temperature range, facilitating artificial irrigation with snowmelt. These favorable conditions are unmatched by other cotton-producing regions. Xinjiang cotton cultivation benefits from fewer types and less severe pests and diseases, particularly the absence of bollworms and the rarity of boll rot, reducing the manpower and costs associated with pest and disease control and significantly lowering production costs. However, the large cotton-growing area in Xinjiang, coupled with manual harvesting methods, puts the already low-profit cotton production at a cost disadvantage.

[0003] With the improvement of living standards and urbanization in my country, a large number of rural laborers have migrated to other areas, leading to a growing labor shortage and increasing labor costs in cotton production. To fundamentally solve the problems in the cotton industry's development, it is essential to improve the mechanization and scale of production. Mechanized harvesting is the most basic requirement in this process. Mechanized cotton harvesting can reduce labor intensity, promote the transformation of cotton planting from intensive to simplified methods, and address issues such as labor shortages in cotton picking and declining cotton planting profits throughout Xinjiang. Mechanized cotton harvesting has become an important way to achieve labor-saving, cost-effective, and efficient cotton production. In recent years, Xinjiang's cotton planting level has consistently been among the best in the country, achieving remarkable results in mechanization, scale, water-saving irrigation, and technological support. In particular, after the Xinjiang Production and Construction Corps implemented mechanized cotton harvesting, mechanized cotton planting reached over 90%. Mechanical harvesting requires cotton varieties to have suitable plant height, high first fruiting branch node, compact plant type, short boll period, good early maturity, concentrated budding, concentrated flowering, concentrated boll formation, concentrated boll opening, good determinate growth characteristics, resistance to lodging, minimal boll rot, few shriveled bolls, smooth boll opening, and strong boll-holding capacity. Simultaneously, due to the loss of cotton fibers during mechanical harvesting, varieties are required to have a fiber length ≥30 mm, specific strength ≥31 cn / tex, and micronaire value of 3.7–4.6. Therefore, research on breeding methods for machine-harvested cotton varieties is beneficial for screening new varieties suitable for machine harvesting and laying a solid foundation for the mechanization and large-scale development of my country's cotton industry. Summary of the Invention

[0004] In view of this, embodiments of the present invention provide a method for breeding machine-harvested cotton varieties. With adaptability to mechanical harvesting as the core objective, the method aims to cultivate cotton varieties with characteristics such as plant morphology suitable for mechanical operation, reasonable boll distribution, and good defoliation.

[0005] To achieve the above objectives, the present invention mainly provides the following technical solutions:

[0006] This invention provides a method for breeding machine-harvested cotton varieties, the method comprising the following steps:

[0007] Step 1: In the first year, crossbreeding was carried out in Xinjiang with parent AY4 and Xinluzao 12 to obtain F1 generation, and individual plants were selected;

[0008] Step 2: In the second year, the F1 generation was self-pollinated in Xinjiang to obtain the F2 generation, and individual plants were selected.

[0009] Step 3: In the third year, F2 generation plants were planted in Xinjiang to select individual plants, and in the same year, superior individual plants were selected in Hainan for breeding.

[0010] Step 4: In the fourth year, F4 generation single plants were obtained through screening in Xinjiang.

[0011] Step 5: From the fifth to the ninth year, select individual plants for planting each year in Xinjiang.

[0012] In a preferred embodiment of the present invention, the selected individual plants refer to those that simultaneously meet the following conditions: ① plant height 80-90cm, initial node height 20-25cm, number of initial nodes 6-8, number of fruiting nodes 15-18, average leaf angle 50-55°, maximum leaf area index (LAI) 3.5-4.0, and average fruiting branch angle 45-50°; ② total growth period 125-130 days, 50% of cotton plants showing buds on the fourth fruiting branch in mid-June, and 50% of cotton plants showing buds on the fourth fruiting branch. It blooms in mid-July, reaches peak bloom in early August, with 50% of cotton plants showing boll formation on the fourth fruiting branch in mid-July, and bolls reaching the top in early September. 50% of cotton plants on the fourth fruiting branch open their bolls in mid-September; ③ Complete flowering ends from August 5th to August 10th; ④ A continuous week of high temperatures reaching 35℃, with a boll formation rate of 80%-85% on the third fruiting branch; ⑤ 0.75-1.5 bolls per branch and 0.45-0.85 bolls per node; ⑥ The boll opening rate reaches over 95% and the defoliation rate reaches 93%-95% within 40 days after spraying defoliant in the cotton field.

[0013] In a preferred embodiment of the present invention, the machine-harvested cotton plant has 8-9 bolls per plant, with a single boll weight of 6-7g and a lint percentage of 40-50%.

[0014] In a preferred embodiment of the present invention, the upper half of the machine-harvested HVICC fiber has an average length of 30-32 mm, a specific strength of 30-32 cN / tex, and a micronaire value of 4-4.5.

[0015] In a preferred embodiment of the present invention, the defoliation rate of the machine-harvested cotton is ≥95%, and the harvesting efficiency is ≥95%.

[0016] In a preferred embodiment of the present invention, the machine-harvested cotton is Yuanmian No. 5.

[0017] Compared with the prior art, the beneficial effects of the present invention are:

[0018] The technical solution of this invention takes adaptability to mechanical harvesting as its core objective. It evaluates and selects key traits of upland cotton for mechanical harvesting, such as plant structure, concentrated maturity, high temperature resistance, easy tip sealing, flower breakage, boll carrying on branches and nodes, and concentrated leaf removal and boll opening. It then selects specific parent plants and offspring single plants and adopts a good propagation system of "self-pollination and mixed propagation" and "same-storage and separate propagation" to cultivate cotton varieties with plant morphology suitable for mechanical operation, reasonable boll distribution, and good leaf removal. Attached Figure Description

[0019] Figure 1 This is a flowchart illustrating the method for breeding machine-harvested cotton varieties;

[0020] Figure 2 This is a schematic diagram of the breeding process of Yuanmian No. 5 in an embodiment of the present invention. Detailed Implementation Plan

[0021] To further illustrate the technical means and effects adopted by the present invention to achieve the intended purpose, the following preferred embodiments are provided to describe in detail the specific implementation methods, technical solutions, features, and effects according to the present invention. Specific features, structures, or characteristics in the various embodiments described below can be combined in any suitable form.

[0022] Example 1: Breeding process of Yuanmian No. 5 (refer to Appendix) Figure 1 and 2 )

[0023] (1) In the first year, the parents were screened, and then the selected parents AY4 and Xinluzao 12 were crossed to obtain the F1 generation. AY4 and Xinluzao 12 are cotton varieties known by existing technology. For example, AY4 has been reported by Wang Junduo et al. "The Spatiotemporal Law of Shedding of Cotton Buds and Bolls in Xinjiang and the Direction of Genetic Improvement", China Cotton Society Annual Meeting 2007, etc., and Xinluzao 12 has been reported by "Key Points of High-Density Cultivation Technology of Xinluzao 12", Xinjiang Agricultural Science and Technology, 2003, (02): 17-18, etc.

[0024] (2) In the second year, the F1 generation was self-pollinated, and the following plants were selected: ① plant height 80-90cm, first node height 20-25cm, number of first nodes 6-8, number of fruiting nodes 15-18, average leaf angle 50-55°, maximum leaf area index (LAI) 3.5-4.0, and average fruiting branch angle 45-50°; ② the entire growth period is 125-130 days, 50% of the cotton plants have buds on the fourth fruiting branch in mid-June, 50% of the cotton plants have buds on the fourth fruiting branch in mid-July, and flowering occurs in early August. By mid-July, 50% of cotton plants will have bolls on their fourth fruiting branches, and by early September, the bolls will be at the top. By mid-September, the bolls on the fourth fruiting branches of 50% of cotton plants will open. ③ From August 5th to August 10th, the flowering will be completely stopped. ④ A continuous week of high temperatures reaching 35℃ will result in a boll formation rate of 80%-85% for the third-tier cotton plants. ⑤ The boll load per branch will be 0.75-1.5, and the boll load per node will be 0.45-0.85. ⑥ After spraying defoliants in the cotton field for 40 days, the boll opening rate will reach over 95%, and the defoliation rate will be 93%-95%. Materials with these results will be used to obtain the F2 generation.

[0025] (3) In the third year, F2 generation will be selected for southern breeding. The key traits of upland cotton for machine harvesting will be evaluated based on plant structure, concentrated maturity, high temperature resistance, easy tip sealing, flower breakage, boll carrying on branches and nodes, and concentrated leaf shedding and boll opening. The following characteristics will be selected: ① Plant height 80-90cm, first node height 20-25cm, number of first nodes 6-8, number of fruiting nodes 15-18, average leaf angle 50-55°, maximum leaf area index (LAI) 3.5-4.0, average fruiting branch angle 45-50°; ② The whole growth period is 125-130 days. 50% of cotton plants will have buds on the fourth fruiting branch in mid-June, 50% of cotton plants will have buds on the fourth fruiting branch in mid-July, and will reach the top of flowering in early August. 50% of cotton plants will have bolls on the fourth fruiting branch in mid-July, and the bolls will reach the top in early September. 50% of cotton plants will have 90% of the fourth fruiting branch bolls. ③ The cotton bolls open in mid-month; ③ The flowering period ends completely from August 5th to August 10th; ④ A continuous week of high temperatures reaching 35℃, with a boll-forming rate of 80%-85% for the third-row cotton plants; ⑤ The boll load per branch is 0.75-1.5, and the boll load per node is 0.45-0.85; ⑥ After spraying defoliants in the cotton field for 40 days, the boll opening rate reaches over 95%, and the defoliation rate reaches 93%-95%. Superior individual plants are selected from these materials. In the fourth year, the F4 generation is used to select individual plants for further testing, followed by evaluation and selection of key traits for machine harvesting of upland cotton, resulting in the selection of excellent individual plants. In the fifth year, these excellent individual plants are planted in rows, and after evaluation and selection of key traits for machine harvesting of upland cotton, excellent individual plants are selected. In the sixth year, after planting individual plants into rows, after evaluation and selection of key traits for machine harvesting of upland cotton, superior rows are selected for harvesting. In the seventh and eighth years, variety comparison trials (i.e., line comparisons) are conducted; in the ninth and tenth years, regional trials and production trials are conducted. Regional trial results: In the early-to-mid-maturing cotton areas of the autonomous region, machine-laid film and manual sowing were used. The growth period was 130 days. The plant was pyramidal in shape, with 8.5 bolls per plant, a single boll weight of 6.3 g, a lint percentage of 43.5%, a seed index of 10.8 g, and a pre-frost boll opening rate of 95.8%. The average length of the upper half of the HVICC fiber was 30.9 mm, the breaking strength was 30.7 cN / tex, and the micronaire value was 4.3.

[0026] Production results for 2017-2018: In the early-to-mid-maturing cotton areas of the autonomous region, machine-mulched planting and manual sowing were used. The entire growth period was 130-135 days. The plant was pyramidal in shape, with type II fruiting branches. The stems were purplish-red with few hairs, and glands were present on the stems and petioles. The leaves were medium-sized, light in color, and had shallow notches. The bolls were long and pointed, with 8.6 bolls per plant, a single boll weight of 6.2 grams, a lint percentage of 43.6%, a seed index of 10.7 grams, and a pre-frost boll opening rate of 96%. The average upper half length of the HVICC fiber was 30.9 mm, the breaking strength was 30.7 cN / tex, and the micronaire value was 4.3. The wilt index was 17.2, and the verticillium wilt index was 7.5. It was resistant to wilt and tolerant to verticillium wilt. In the same year, Yuanmian No. 5 was obtained.

[0027] Example 2: Application of Yuanmian No. 5

[0028] 1. Experimental Location: Cotton Comprehensive Experimental Base of Xinjiang Academy of Agricultural Sciences, 16th Regiment, Alar.

[0029] 2. Trial period: 2018

[0030] 3. Experimental Procedure:

[0031] Experimental materials: Seeds of the tested upland cotton parental materials (all from the Cotton Molecular Genetic Improvement and Innovation Team of the Cotton Research Institute, Xinjiang Academy of Agricultural Sciences).

[0032] 4. Test methods:

[0033] Sowing is carried out from April 10th to 15th, using drip irrigation under mulch film and a machine-harvested cotton planting pattern of six rows per mulch film (66 cm + 10 cm). The yield is approximately 13,000-15,000 plants per mu (approximately 0.067 hectares), requiring uniform plant density. Yuanmian No. 5 is a robust cotton variety. The first chemical control is applied at the three-to-four-leaf stage, followed by chemical control every 3-4 main stem leaves, with the dosage adjusted according to seedling growth. Full-layer fertilization is required, with approximately 150 kg of standard fertilizer per mu. Drip-irrigated cotton fields receive 8-10 irrigations throughout the growing season, using approximately 300 cubic meters of water; conventionally irrigated cotton fields receive 3-4 irrigations throughout the growing season, using approximately 400-450 cubic meters of water. Field management is the same as in open-field production. Topping begins in early July and ends on July 5th in the northern Xinjiang cotton-growing areas; in southern Xinjiang, topping ends on July 10th, leaving approximately 9 fruiting branches per plant. For pests such as cotton aphids and bollworms that cause serious damage, the principle of prevention first, combined with control and integrated management should be implemented. It is necessary to do a good job in forecasting and early warning of pests, so as to predict, detect and control them early, control the spread of pests, avoid large-scale use of pesticides as much as possible, protect and utilize natural enemies, reduce the amount and frequency of pesticide use, reduce costs and protect the environment.

[0034] 5. Conclusion:

[0035] (1) Basic characteristics: early maturity, wide adaptability, high and stable yield, high quality and disease resistance, strong boll setting ability, suitable for harvesting, and easy to manage.

[0036] (2) The growing period is 130-135 days. It matures quickly and has a concentrated flowering period. 96% of the flowers bloom before the first frost.

[0037] (3) Yield characteristics: 8.6 bolls per plant, 6.2g weight per boll, 43.6% lint percentage, 10.7g seed index, and more than 15% yield increase in production trials.

[0038] (4) Quality characteristics: The average length of the upper half of HVICC fiber is 30.9 mm, the specific strength is 30.7 cN / tex, and the micron value is 4.3. The length, strength and fineness are reasonably matched, making it suitable for spinning high-count yarn.

[0039] (5) Disease resistance: High resistance to Fusarium wilt (Fusarium wilt index 17.2), and tolerant to Verticillium wilt (Verticillium wilt index 7.5).

[0040] (6) Suitable for harvesting: good defoliation, defoliation rate ≥95%, good leaf shedding, clean harvesting rate ≥95%, good harvesting quality, and possesses multiple machine-harvesting characteristics.

[0041] Yuanmian No. 5 has a pyramidal plant structure, type II fruit branches, purplish-red stems with fewer hairs, glands on stems and petioles, medium-sized leaves with light color and shallow notches, and long, pointed bolls. The variety has a tall boll-bearing structure with bare stems, bare leaves, and large bolls. The spatial structure of boll formation is more optimized, and the genetic traits are suitable for high-density, machine-harvested, quantity-quality coordinated, and efficient water and fertilizer application patterns. The plant structure configuration is more reasonable.

[0042] Its short internode structure, short petiole structure, staggered structure, and numerous bolls with few leaves result in a rational spatial and temporal configuration of branches, leaves, buds, and bolls, ensuring good ventilation, light penetration, and preventing boll rot, while also enhancing the light transmittance coefficient. The core of this structural design is bright, well-ventilated, and highly permeable light, suitable for high-density planting. The core of the concentrated ripening structural design is centralized, one-time harvesting and efficient resource utilization.

[0043] Type II fruit branch structure breaks away from the traditional fruit branch structure design, enabling machine harvesting and reducing loss of traits. The core of this structural selection design is machine harvesting, which is a structural design breeding that is suitable for and facilitates mechanical harvesting.

[0044] The Yuanmian No. 5 variety features a disease-resistant, heat-tolerant, and resource-efficient structure that enhances varietal productivity under abiotic stress. The core of this structural design is adaptability, built upon structural foundations such as ventilation, light penetration, and concentrated ripening.

[0045] Stable internode structure and suitable medium-to-tall main stem structure design, short internode structure, fewer leaves and more bolls structure, and reduction of ineffective and redundant structures are key considerations. Studies have found that instability in individual plants within a population is closely related to plant structure. Stable internode structure is less affected by the environment. The core of this structural selection design is stability, which is a structural design that is easy to manage.

[0046] Yuanmian No. 5 exhibits good synergy in economic traits, achieving a synergistic improvement in multiple traits. It overcomes the contradiction between yield and quality, and the negative correlation between early maturity and disease resistance. These changes are related to structural changes and are the result of comprehensive configuration of plant type and genetic background structure. These structural changes improve the variety's suitability for harvesting, ease of management, high efficiency, synergy, monopolistic characteristics, and recognizability. All structural changes serve the improvement of superior traits.

[0047] For any aspects not covered in the embodiments of this invention, those skilled in the art can choose from the prior art. The above disclosures are merely specific embodiments of this invention, but the scope of protection of this invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this invention should be included within the scope of protection of this invention. Therefore, the scope of protection of this invention should be determined by the scope of the above claims.

Claims

1. A method for breeding a machine-picked cotton variety, the method comprising the following steps: Step 1: In the first year, crossbreed parent AY4 and Xinluzao No. 12 in Xinjiang to obtain F1 generation, and select single plants; Step 2: In the second year, self-cross the F1 generation in Xinjiang to obtain F2 generation, and select single plants; Step 3: In the third year, plant the F2 generation selected single plants in Xinjiang, and at the same time, perform southward propagation in Hainan to select excellent single plants; Step 4: In the fourth year, obtain F4 generation by adding generations in Xinjiang, and select single plants; Step 5: In the fifth to ninth years, select single plants for planting in Xinjiang every year.

2. The method of claim 1, wherein the selection of single plants in steps 1-5 refers to the selection of single plants that meet the following conditions at the same time: ① plant height 80-90 cm, initial node height 20-25 cm, initial node number 6-8, fruit node number 15-18, average leaf inclination angle 50-55°, maximum leaf area index (LAI) 3.5-4.0, and average fruit branch angle 45-50°; ② whole growth period 125-130 days, 50% of the fourth fruit branches of cotton plants bloom in mid-June, 50% of the fourth fruit branches of cotton plants bloom in mid-July, and the top blooms in early August, 50% of the fourth fruit branches of cotton plants can see bolls in mid-July, the top bolls in early September, and 50% of the fourth fruit branches of cotton plants shed bolls in mid-September; ③ complete flower shedding from August 5 to August 10; ④ continuous high temperature of 35°C for one week, and 80%-85% of the bolls are formed at the third node from the bottom; ⑤ branch boll load 0.75-1.5, and node boll load 0.45-0.85; ⑥ cotton field spraying of defoliating agent for 40 days to achieve a shedding rate of more than 95%, and the defoliation rate of the material is 93%-95%.

3. The method of claim 2, wherein the machine-picked cotton has 8-9 bolls per single plant, a single boll weight of 6-7 g, and a lint percentage of 40-50%.

4. The method of claim 2, wherein the machine-picked cotton has an average length of 30-32 mm, a specific strength of 30-32 cN / tex, and a micronaire value of 4-4.5 in the upper half of the HVICC fiber.

5. The method of claim 2, wherein the machine-picked cotton has a defoliation rate of ≥95% and a clean picking rate of ≥95%.

6. The method of claim 2, wherein the machine-picked cotton is Source Cotton No. 5.

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