High-temperature-resistant breeding method for asparagus beans in flowering and pod period and application

Abstract

The invention belongs to the technical field of plant breeding, and particularly relates to a high-temperature-resistant asparagus bean breeding method in a flowering and pod period, which comprises the following steps: selecting a high-temperature-resistant asparagus bean female parent and a male parent with excellent comprehensive characters; hybridizing the male parent and the female parent, and harvesting first-filial generation seeds; high-temperature stress: setting a high-temperature condition of 35-45 DEG C, putting the first-filial generation seeds into soil added with a stress agent, and cultivating the first-filial generation seeds to a seedling stage under the illumination intensity of 7000-8000 lux and the illumination time of 8-10 hours; the stress agent is sodium sulfate or sodium hydrogen sulfite, and the dosage of the stress agent is 0.1-0.2 g / kg of soil; seedlings with the height capable of growing to 25 cm or above are transplanted, field management is carried out till the seedlings are mature, second-generation seeds are harvested, and after continuous selfing is carried out for multiple generations, high-temperature-resistant plants with stable characters are obtained. According to the method, the high-temperature-resistant seed material can be accurately screened out in the seedling stage, the consumed time is short, and the workload required by filial generation identification is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of plant breeding, and particularly relates to a high temperature resistant breeding method for cowpea during the flowering and pod stage. Background Art

[0002] As an important vegetable crop of the genus Vigna in the leguminous family, the young pods of cowpea are rich in various nutrients such as protein, dietary fiber, vitamins and minerals. They can not only be eaten fresh, but also processed into various products, and are deeply favored by consumers.

[0003] In the growth cycle of cowpea, the flowering and pod stage is a key stage that determines the yield and quality. At this stage, the growth center of the plant shifts from vegetative growth to reproductive growth, and a large amount of nutrients and energy are consumed for flower bud differentiation, flowering, pollination and fertilization, and pod development. Whether the flower bud differentiation is normal and whether the pollination and fertilization are smooth directly affect the quantity and quality of flower pods. If the environmental conditions at this stage are suitable, which is about 25℃ to 28℃, the plant can form more effective flower pods, and the pods are well developed and the grains are full, thus achieving the goal of high yield and high quality. The cowpea plants in the flowering and pod stage are extremely sensitive to environmental conditions. The frequent occurrence of extreme high temperature weather, such as the ambient temperature exceeding 35℃ during the flowering and pod stage, will bring severe challenges to the growth of cowpea in the flowering and pod stage. High temperature will cause abnormal differentiation of cowpea flower buds, reduced pollen vitality, and obstructed pollination and fertilization, which will cause a large number of flowers and pods to fall, seriously affecting the yield. High temperature may also cause physiological metabolic disorders in plants and cause premature aging of plants. For example, under high temperature stress, the expression of key genes for the synthesis of auxin in long beans is inhibited, resulting in a decrease in the amount of auxin synthesis. Insufficient auxin content will affect the normal development of flower organs, leading to abnormal flower morphology and structure, and reducing flower quality and fertility. The reduction in gibberellins and cytokinins will also affect cell elongation and division, thereby affecting the growth and development of flower pods. In view of the above situation, it is very necessary to carry out high temperature resistance breeding of long beans during the flowering and pod stage.

[0004] Hybrid breeding is a common method for breeding new high-temperature resistant varieties of cowpea. Hybrid breeding is achieved by hybridizing cowpea varieties with different excellent traits to achieve gene recombination and aggregation of excellent traits. When selecting parents, one party should have good high-temperature resistance, such as high pollen vitality and normal flower and pod development under high temperature; the other party should have other excellent traits, such as high yield, high quality, and disease resistance. After the hybrid seeds of the parents are planted, they usually show hybrid vigor. They need to be observed and screened under high temperature to eliminate those plants that do not meet the high temperature resistance requirements. However, the hybrid seed population after parental hybridization is large. If large-scale planting, screening and identification are carried out, the performance of the traits of each plant, such as high temperature resistance, yield, quality, etc., will be observed and recorded. It takes a long time and requires a lot of work.

[0005] In summary, it is necessary to develop a time-saving breeding method for high temperature tolerance during the flowering and pod stage of cowpea. Summary of the invention

[0006] In order to solve the above technical problems, the present invention provides a method for breeding cowpea with high temperature resistance during the flowering and pod stage, which can cultivate cowpea plants with high temperature resistance during the flowering and pod stage.

[0007] The object of the present invention is to provide a method for breeding cowpeas to withstand high temperatures during the flowering and podning period, comprising:

[0008] Select high temperature resistant long cowpea female parent and excellent comprehensive traits male parent;

[0009] The male parent is hybridized with the female parent to harvest the first generation of hybrid seeds;

[0010] High temperature stress: set a high temperature condition of 35°C to 45°C, place the hybrid first-generation seeds in soil added with a stress agent, light intensity of 7000lux to 8000lux and light time of 8h to 10h, and cultivate until the seedling stage; the stress agent is sodium sulfate or sodium bisulfite, and the amount of the stress agent is 0.1g / kg soil to 0.2g / kg soil;

[0011] The seedlings that can grow to a height of more than 25 cm are transplanted, managed in the field until maturity, and the second-generation seeds are harvested. After continuous self-pollination for multiple generations, high-temperature-resistant plants with stable traits are obtained.

[0012] Preferably, in the above-mentioned method for breeding cowpea for high temperature resistance during the flowering and pod stage, the high temperature condition is 40°C.

[0013] Preferably, in the above-mentioned method for breeding cowpea for high temperature resistance during the flowering and pod stage, the high temperature condition is provided in an artificial climate incubator.

[0014] Preferably, in the above-mentioned cowpea breeding method for high temperature resistance during the flowering and pod stage, the dosage of the stress agent is 0.1g / kg soil to 0.15g / kg soil, such as 0.1g / kg soil, 0.11g / kg soil, 0.12g / kg soil, 0.13g / kg soil, 0.14g / kg soil and 0.15g / kg soil.

[0015] Preferably, the above-mentioned method for breeding cowpea for high temperature resistance during the flowering and pod stage further comprises: adjusting the ambient temperature to 35°C to 40°C during the flowering and pod stage after transplanting.

[0016] Preferably, in the above-mentioned method for breeding cowpea for high temperature resistance during the flowering and pod stage, the seeds of each generation of hybridization are subjected to high temperature stress and then transplanted to screen out high temperature resistant plants.

[0017] The invention provides application of the stress agent in cultivating high temperature resistant cowpea plants during the flowering and pod stage.

[0018] Preferably, the application includes cultivating cowpea plants that can withstand temperatures of 35°C to 45°C during the flowering and podning period.

[0019] Preferably, the application also includes improving the quality of long beans.

[0020] Preferably, the quality measurement index of the long beans includes improving the quality of the long beans including increasing the protein content, vitamin C content, total sugar content and yield.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The invention selects a high-temperature-resistant cowpea female parent and a male parent with excellent comprehensive traits, hybridizes the male parent with the female parent, and harvests hybrid first-generation seeds. In combination with high-temperature stress, transplanting seedlings with a height of more than 25 cm and other field management measures, high-temperature-resistant seed materials can be accurately screened out in the seedling stage, which saves time and can reduce the workload required for hybrid offspring identification.

[0023] The method of the present invention further comprises adjusting the ambient temperature to 35° C. to 40° C. during the flowering and pod stage after transplanting, which is helpful to improve the accuracy of screening cowpea plants resistant to high temperature during the flowering and pod stage.

[0024] The present invention can effectively reduce the adverse effects of high temperature stress on the production of long cowpea by cultivating a new long cowpea variety with good high temperature resistance during the flowering and pod stage, thereby ensuring a stable supply of long cowpea and meeting market demand, and can also provide growers with more stress-resistant variety options, reduce planting risks, and increase economic benefits. DETAILED DESCRIPTION

[0025] In order to enable those skilled in the art to better understand and implement the technical solution of the present invention, the present invention is further described below in conjunction with specific embodiments.

[0026] In the description of the present invention, unless otherwise specified, all reagents used are commercially available and all methods used are conventional techniques in the art.

[0027] The inventive concept of the present invention is as follows:

[0028] Given that the flowering and pod stage of cowpea is sensitive to temperature, it is necessary to carry out high temperature resistant breeding of cowpea during the flowering and pod stage. Hybrid breeding is a common method to breed new high temperature resistant cowpea varieties, but the hybrid seed population after parental hybridization is large. If large-scale planting screening and identification are carried out, it will take a long time and require a lot of work to observe and record the performance of each plant, such as high temperature resistance, yield, quality, etc.

[0029] The present invention provides a method for breeding cowpeas to resist high temperatures during the flowering and podning stage, comprising:

[0030] 1. Select a high temperature resistant cowpea female parent and a male parent with excellent comprehensive traits; the male and female parents can be derived from local varieties, wild related species and existing cultivated varieties.

[0031] 2. Hybridize the male parent with the female parent and harvest the first-generation hybrid seeds.

[0032] 3. High temperature stress:

[0033] The high temperature condition of 35℃~45℃ was set, and the hybrid first-generation seeds were placed in the soil with stress agent added, so as to create a high temperature stress environment and realize the high temperature stress treatment of the long cowpea hybrid first-generation seeds. Cultivate until the seedling stage.

[0034] The lighting conditions from cultivation to the seedling stage are light intensity 7000 lux to 8000 lux and lighting time 8h to 10h. This lighting condition combined with high temperature and stress agent helps to accurately screen out heat-resistant materials during high temperature stress treatment. The seedling height of heat-intolerant materials is always less than 25cm.

[0035] The seedlings that can grow to a height of more than 25 cm are transplanted, managed in the field until maturity, and the second-generation seeds are harvested. After continuous self-pollination for multiple generations, high-temperature-resistant plants with stable traits are obtained.

[0036] In addition, the ambient temperature can be adjusted to 35℃~40℃ during the flowering and pod formation stage to further screen and verify high temperature resistant plants. By observing the growth of long beans, recording the number of pods and flower drop rate, those that can bloom and bear fruit normally are considered to be high temperature resistant strains. The obtained high temperature resistant strains can all withstand high temperatures of 35℃~40℃.

[0037] The present invention adopts a simple screening method, which is time-saving and can accurately screen out high-temperature resistant seed materials in the seedling stage, thereby reducing the workload required for hybrid offspring identification.

[0038] The present invention includes the following specific embodiments.

[0039] Example 1

[0040] A method for breeding cowpeas to resist high temperatures during the flowering and podning stage, comprising:

[0041] 1. Select the high temperature resistant long cowpea female parent Jingyi 508 and the male parent Hua21 with excellent comprehensive traits.

[0042] 2. Hybridize the male parent with the female parent and harvest the first-generation hybrid seeds. The detailed steps are as follows:

[0043] 2.1. Soil preparation: Cowpea is suitable for planting in loose, fertile, well-drained soil. Before planting, the soil should be deeply plowed to a depth of 25 cm. Combine deep plowing with basal fertilizer. Before deep plowing, apply 3,000 kg of decomposed farmyard manure, 20 kg of superphosphate, and 10 kg of potassium sulfate per mu. Sprinkle the fertilizer evenly on the soil surface, and then deep plow to fully mix the fertilizer with the soil.

[0044] 2.2. Before sowing, expose the cowpea seeds to the sun for 2 days to increase the germination rate. In Henan Province, open-field cultivation in spring is sown in late March. During this period, the temperature gradually warms up, and the soil temperature is suitable for the germination of cowpea seeds. Dig holes with a row spacing of 60 cm and a plant spacing of 25 cm, sow 3 cowpea seeds in each hole, and sow 4 cm deep. Cover with soil after sowing, compact lightly, and water sufficiently.

[0045] 2.3 Field management

[0046] 2.3.1 Thinning and transplanting: Thinning should be done when the cowpea seedlings have 3 true leaves, leaving 2 strong seedlings in each hole. Transplanting should be done when the seedlings have 5 true leaves to ensure a reasonable distribution of plants.

[0047] 2.3.2 Fertilization: In the seedling stage, 5 kg of urea is applied per mu to promote the growth of seedlings. The flowering and podding stage is the key period for cowpea to require fertilizer. 15 kg of nitrogen, phosphorus and potassium compound fertilizer (N:P:K=15:15:15) is applied per mu. Water in time after fertilization to promote fertilizer absorption.

[0048] 2.3.3. During the flowering period of cowpea, artificial emasculation and pollination are performed. Specifically, before the female flower blooms, the stamens are removed to prevent self-pollination. Then, when the male flower blooms and the pollen matures, the male pollen is collected with a brush or other tools and applied to the stigma of the female plant to complete the pollination process. The field management is continued until the cowpea matures, and the hybrid first-generation seeds are harvested.

[0049] 2.3.4. Watering: Pay attention to timely watering during the growth of cowpea. Keep the soil dry and moist during the seedling stage. The water demand is relatively large during the flowering and pod-setting stage. The soil should be kept moist but not waterlogged. After heavy rains in summer, drainage should be carried out in time to prevent waterlogging in the field and cause root diseases.

[0050] 2.3.5. Build a trellis to guide the vines: When the cowpea plants grow to 30 cm in height, start building a trellis. Gently wrap the cowpea vines around the trellis to guide them to grow upward.

[0051] 2.3.6. Pest and disease control

[0052] Disease control: Common diseases of cowpea in Henan are rust and anthracnose. In the early stage of rust, 12.5% ​​diniconazole wettable powder 2000 times liquid can be used for spraying. Anthracnose mainly harms pods and leaves, and 70% thiophanate-methyl wettable powder 800 times liquid can be used for spraying.

[0053] Pest control: During the flowering and pod-setting stages, spray 3000 times diluted 20% chlorfenapyr suspension for pest control.

[0054] 3. High temperature stress

[0055] A high temperature condition of 35°C was set in an artificial climate incubator, and the hybrid first-generation seeds were planted in soil with stress agents added, thereby creating a high temperature stress environment and achieving high temperature stress treatment of the long cowpea hybrid first-generation seeds. The types and amounts of stress agents are shown in Table 1. The soil was garden soil.

[0056] The light intensity was 7000 lux and the illumination time was 8 h.

[0057] After the seedlings are transplanted to the greenhouse environment, refer to the field management method in 2.3 for field management. Observe the growth of long beans, record the number of pods, flower drop rate, and plant growth rate. Select germplasm resources with normal pod number, normal flower drop rate, and plants greater than or equal to 25 cm under high temperature stress as candidate materials for high temperature resistance.

[0058] 100 hybrid first-generation seeds were randomly selected, and the screening results are shown in Table 2.

[0059] 4. Self-pollinate the first generation of high temperature resistant hybrids selected in the third step, manage them in the field until maturity, harvest the second generation seeds, and after continuous self-pollination for multiple generations, select plants with good flower and pod development under high temperature. As the number of self-pollination generations increases, the genes gradually become homozygous, and the traits of the plants become more stable. In the screening process of each generation, not only high temperature resistance should be paid attention to, but also other agronomic traits, such as yield, quality, and disease resistance. Select those plants that are both resistant to high temperatures and have excellent comprehensive traits as materials for subsequent variety breeding. Refer to the field management method in 2.3 for field management.

[0060] Example 2

[0061] A method for breeding cowpeas to resist high temperatures during the flowering and podning stage, comprising:

[0062] 1. Select the high temperature resistant long cowpea female parent Jingyi 508 and the male parent Hua21 with excellent comprehensive traits.

[0063] 2. Hybridize the male parent with the female parent and harvest the first-generation hybrid seeds. The detailed steps are as follows:

[0064] 2.1. Soil preparation: Cowpea is suitable for planting in loose, fertile, well-drained soil. Before planting, the soil should be deeply plowed to a depth of 25 cm. Combine deep plowing with basal fertilizer. Before deep plowing, apply 3,000 kg of decomposed farmyard manure, 20 kg of superphosphate, and 10 kg of potassium sulfate per mu. Sprinkle the fertilizer evenly on the soil surface, and then deep plow to fully mix the fertilizer with the soil.

[0065] 2.2. Before sowing, expose the cowpea seeds to the sun for 2 days to increase the germination rate. In Henan Province, open-field cultivation in spring is sown in late March. During this period, the temperature gradually warms up, and the soil temperature is suitable for the germination of cowpea seeds. Dig holes with a row spacing of 60 cm and a plant spacing of 25 cm, sow 3 cowpea seeds in each hole, and sow 4 cm deep. Cover with soil after sowing, compact lightly, and water sufficiently.

[0066] 2.3 Field management

[0067] 2.3.1 Thinning and transplanting: Thinning should be done when the cowpea seedlings have 3 true leaves, leaving 2 strong seedlings in each hole. Transplanting should be done when the seedlings have 5 true leaves to ensure a reasonable distribution of plants.

[0068] 2.3.2 Fertilization: In the seedling stage, 5 kg of urea is applied per mu to promote the growth of seedlings. The flowering and podding stage is the key period for cowpea to require fertilizer. 15 kg of nitrogen, phosphorus and potassium compound fertilizer (N:P:K=15:15:15) is applied per mu. Water in time after fertilization to promote fertilizer absorption.

[0069] 2.3.3. During the flowering period of cowpea, artificial emasculation and pollination are performed. Specifically, before the female flower blooms, the stamens are removed to prevent self-pollination. Then, when the male flower blooms and the pollen matures, the male pollen is collected with a brush or other tools and applied to the stigma of the female plant to complete the pollination process. The field management is continued until the cowpea matures, and the hybrid first-generation seeds are harvested.

[0070] 2.3.4. Watering: Pay attention to timely watering during the growth of cowpea. Keep the soil dry and moist during the seedling stage. The water demand is relatively large during the flowering and pod-setting stage. The soil should be kept moist but not waterlogged. After heavy rains in summer, drainage should be carried out in time to prevent waterlogging in the field and cause root diseases.

[0071] 2.3.5. Build a trellis to guide the vines: When the cowpea plants grow to 30 cm in height, start building a trellis. Gently wrap the cowpea vines around the trellis to guide them to grow upward.

[0072] 2.3.6. Pest and disease control

[0073] Disease control: Common diseases of cowpea in Henan are rust and anthracnose. In the early stage of rust, 12.5% ​​diniconazole wettable powder 2000 times liquid can be used for spraying. Anthracnose mainly harms pods and leaves, and 70% thiophanate-methyl wettable powder 800 times liquid can be used for spraying.

[0074] Pest control: During the flowering and pod-setting stages, spray 3000 times diluted 20% chlorfenapyr suspension for pest control.

[0075] 3. High temperature stress

[0076] A high temperature condition of 35°C was set in an artificial climate incubator, and the hybrid first-generation seeds were planted in soil with stress agents added, thereby creating a high temperature stress environment and achieving high temperature stress treatment of the long cowpea hybrid first-generation seeds. The types and amounts of stress agents are shown in Table 1. The soil was garden soil.

[0077] The light intensity was 7000 lux and the illumination time was 8 h.

[0078] When the seedlings are transplanted to the greenhouse environment, the field management is carried out according to the field management method in 2.3. In addition, the ambient temperature is adjusted to 35℃ during the flowering and pod stage to screen and verify the high temperature resistance.

[0079] Observe the growth of long beans, record the number of pods, flower drop rate, and plant growth rate. Select germplasm resources with normal pod number and flower drop rate under high temperature stress and plants greater than or equal to 25 cm as candidate materials for high temperature resistance.

[0080] 100 hybrid first-generation seeds were randomly selected, and the screening results are shown in Table 2.

[0081] 4. Self-pollinate the first generation of high temperature resistant hybrids selected in the third step, manage them in the field until maturity, harvest the second generation seeds, and after continuous self-pollination for multiple generations, select plants with good flower and pod development under high temperature. As the number of self-pollination generations increases, the genes gradually become homozygous, and the traits of the plants become more stable. In the screening process of each generation, not only high temperature resistance should be paid attention to, but also other agronomic traits, such as yield, quality, and disease resistance. Select those plants that are both resistant to high temperatures and have excellent comprehensive traits as materials for subsequent variety breeding. Refer to the field management method in 2.3 for field management.

[0082] The condition settings and differences between different embodiments and controls are shown in Table 1.

[0083] Table 1 Conditions of different embodiments and controls

[0084]

[0085]

[0086] Note: “ / ” indicates no stress agent was added.

[0087] The test results are shown in Table 2, which shows the growth of hybrid first-generation seeds after high temperature stress. Each group randomly selected 100 hybrid first-generation seeds for the experiment. When the seedling height can grow to more than 25 cm, it is considered to be a high-temperature resistant plant. The plant is transplanted and the number of pods and flower drop rate of each plant are tested. At the same time, the quality of long cowpea is tested, such as protein content, vitamin C content, total sugar content, and yield. Table 2 only counts the number of plants with protein content, vitamin C content, total sugar content, and yield above a certain value. When these values ​​are reached, it is considered that the long cowpea has good quality and is resistant to high temperatures during the flowering and pod period.

[0088] The number of pods per long cowpea plant is more than 40, and the flower drop rate is less than or equal to 20%, which is considered to be a high temperature resistant plant. From the comparison results of Example 1 to Example 2 in Table 2, it can be seen that when the ambient temperature during the flowering and pod period is 35°C, the number of plants counted is not much different from the ambient temperature of the flowering and pod period, indicating that the method of the present invention can screen out high temperature resistant long cowpea plants during the flowering and pod period. By comparing Example 1 and Example 3 to Example 4, it can be seen that the influence of different high temperature stress temperatures on the screening results of high temperature resistant long cowpea plants can be seen. When high temperature stress is carried out in the range of 35°C to 45°C, the number of plants screened out is at least 27. By comparing Example 1 with Example 6 to Example 9, when the light intensity is 7000lux to 8000lux, the light time is 8h to 10h, the stress agent is sodium sulfate or sodium sulfite, and the amount of the stress agent is 0.1g / kg soil to 0.2g / kg soil, the number of high temperature resistant plants screened out during the flowering and pod period is at least 25. The seeds of blank control 1 were not subjected to any high temperature treatment. When the seeds were subjected to 35℃ high temperature treatment during the flowering and pod stage, the number of qualified high temperature resistant cowpea plants was greatly reduced compared with the number of qualified seedlings, indicating that there were many plants in the seedling stage that were not resistant to high temperature. Blank control 2 was a case of growth in a non-high temperature environment. Since there was no high temperature effect, the number of qualified cowpea plants was large. Blank control 3 was a case of only 35℃ high temperature treatment without adding stress agents. The results showed that among the seedlings with a height of more than 25cm, the number of qualified cowpea plants decreased after screening and verification at 35℃ during the flowering and pod stage, indicating that there were still some false positive results in the early high temperature treatment. Control experiments 1 to 4 were respectively too low light intensity (6000lux), too high light intensity (8000lux), too low light time (7h), and too high light time (8h). The number of qualified cowpea plants resistant to high temperature during the flowering and pod stage was small.

[0089] After the seedlings screened out in each embodiment matured, the number of plants with qualified protein content, vitamin C content, total sugar content and yield was also large, indicating that many effective seedlings were screened out with high accuracy.

[0090] Table 2 Growth of hybrid first generation seeds after high temperature stress

[0091]

[0092] Correlated physiological indicators, the results of Table 2 are deeply analyzed as follows:

[0093] The number of pods directly reflects the yield potential. Each pod contains a certain number of seeds. The more pods there are, the higher the potential yield of the cowpea plant. The number of pods also reflects the growth vitality and reproductive ability of the plant. The large number of pods indicates that the plant is growing robustly, the nutrients are adequately supplied, and the energy and nutrients produced by photosynthesis can be successfully used for reproductive growth. In Table 2, after the transplanted seedlings of Examples 1 to 9 grow, the number of pods per cowpea inflorescence is at least 26 plants with more than 4 pods, and the proportion relative to the number of transplanted seedlings is more than 87%. Since the blank control 1 to the blank control 2 were not subjected to high temperature treatment after sowing, the proportion of the number of cowpea plants with qualified quality was significantly reduced after the seedlings were transplanted to the greenhouse. In control experiments 1 to 4, although there was a high temperature treatment of 40°C, the light time and light conditions were not suitable, and no stress agent was used, so even if a large number of seedlings were qualified, the number of mature cowpea plants with qualified quality was poor.

[0094] The flower drop rate reflects reproductive efficiency: the flower drop rate is an indicator to measure the success of the reproductive process of cowpea. It reflects the adaptability of the plant to the environment and the internal physiological coordination. In Table 2, the number of transplanted seedlings of Examples 1 to 9 with a flower drop rate ≤ 20% after growth is at least 26, and the proportion relative to the number of transplanted seedlings is more than 87%. Since blank control 1 to blank control 2 were not subjected to high temperature treatment after sowing, the proportion of cowpea plants with qualified quality was significantly reduced after their seedlings were transplanted to the greenhouse. In control experiments 1 to 4, although there was a high temperature treatment of 40°C, the lighting time and lighting conditions were not suitable, and no stress agents were used. Therefore, even if a large number of seedlings were qualified, the number of mature cowpea plants with qualified quality was poor.

[0095] Protein content is a reflection of nutritional value. Protein is one of the essential nutrients for the human body and is essential for physiological processes such as human growth and development, cell repair, etc. Long beans with high protein content can provide consumers with richer nutrition. Different varieties of long beans may have different protein contents, and protein content can be used as an important basis for the identification of long bean variety quality. In the process of long bean variety breeding, breeding varieties with high protein content can improve the nutritional value and market competitiveness of long beans. In Table 2, the number of transplanted seedlings with a protein content of ≥2.0g / kg after maturity of Examples 1 to 9 is at least 25, and the proportion relative to the number of transplanted seedlings is more than 85%. Since blank controls 1 to 2 were not subjected to high temperature treatment after sowing, the proportion of long beans with qualified quality was significantly reduced after their seedlings were transplanted to the greenhouse. In control experiments 1 to 4, although there was a high temperature treatment of 40°C, the lighting time and lighting conditions were not suitable, and no stress agent was used. Therefore, even though a large number of seedlings were qualified, the number of mature cowpea plants with qualified quality was significantly reduced compared with the embodiments.

[0096] Vitamin C is an antioxidant that has many benefits for human health, such as enhancing immunity and promoting collagen synthesis. The level of vitamin C content in long beans directly affects its nutritional and health value. The content of vitamin C in plants will decrease with the extension of storage time and changes in environmental conditions. To a certain extent, the vitamin C content in long beans can reflect its freshness and quality. In Table 2, the vitamin C content of the transplanted seedlings of Examples 1 to 9 after maturity is ≥ 18.0 mg / kg for at least 25 plants, and the proportion relative to the number of transplanted seedlings is more than 85%. After the seedlings of blank control 1 to blank control 2 were transplanted to the greenhouse, the proportion of qualified long beans was significantly reduced. In control experiments 1 to 4, although there was a high temperature treatment of 40°C, the lighting time and lighting conditions were not suitable, and no stress agent was used. The number of mature long beans with qualified quality was significantly reduced compared with each embodiment.

[0097] Total sugar content is one of the important factors affecting the taste and flavor of cowpea. A higher total sugar content can make cowpea taste sweeter and increase its palatability. In Table 2, the number of transplanted seedlings of Examples 1 to 9 with a total sugar content ≥ 2.0g / kg after maturity is at least 25, and the proportion relative to the number of transplanted seedlings is more than 85%. After the seedlings of blank control 1 to blank control 2 were transplanted to the greenhouse, the proportion of cowpeas with qualified quality was significantly reduced. In control experiments 1 to 4, although there was a high temperature treatment of 40°C, the lighting time and lighting conditions were not suitable, and no stress agent was used. The number of mature cowpeas with qualified quality was significantly reduced compared with each embodiment.

[0098] Yield is the key to economic benefits. Higher yield means that growers can obtain more agricultural products for sale, thereby increasing economic income. For example, in a farm that grows cowpea on a large scale, the level of yield directly determines the economic benefits of the farm. In Table 2, the number of transplanted seedlings with a yield ≥1.0kg / plant after maturity in Examples 1 to 9 is at least 25 plants, and the proportion relative to the number of transplanted seedlings is more than 85%. After the seedlings of blank control 1 to blank control 2 were transplanted to the greenhouse, the proportion of cowpea plants with qualified quality was significantly reduced. In control experiments 1 to 4, although there was a high temperature treatment of 40°C, the lighting time and lighting conditions were not suitable, and no stress agent was used. The number of mature cowpea plants with qualified quality was significantly reduced compared to the various examples.

[0099] It should be noted that when the present invention involves a numerical range, it should be understood that the two endpoints of each numerical range and any value between the two endpoints can be selected. Since the steps and methods used are the same as those in the embodiments, in order to avoid redundancy, the present invention describes a preferred embodiment. Although the preferred embodiments of the present invention have been described, once those skilled in the art know the basic inventive concept, they can make other changes and modifications to these embodiments, and these changes and modifications all fall within the scope of the present invention.

[0100] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. If these modifications and variations of the present invention fall within the scope of the equivalent technology of the present invention, the present invention is also intended to include these modifications and variations.

Claims

1. A method for breeding cowpea for high temperature resistance during flowering and pod stage, characterized in that: include: Select high temperature resistant long cowpea female parent and excellent comprehensive traits male parent; The male parent is hybridized with the female parent to harvest the first generation of hybrid seeds; High temperature stress: set a high temperature condition of 35°C to 45°C, place the hybrid first-generation seeds in soil added with a stress agent, and cultivate them to the seedling stage under the conditions of a light intensity of 7000lux to 8000lux and a light duration of 8h to 10h; the stress agent is sodium sulfate or sodium bisulfite, and the amount of the stress agent is 0.1g / kg soil to 0.2g / kg soil; The seedlings that can grow to a height of more than 25 cm are transplanted, managed in the field until maturity, and the second-generation seeds are harvested. After continuous self-pollination for multiple generations, high-temperature-resistant plants with stable traits are obtained.

2. The method for breeding cowpea for high temperature resistance during flowering and pod stage according to claim 1, characterized in that: The temperature of the high temperature condition is 40°C.

3. The method for breeding cowpea for high temperature resistance during flowering and pod stage according to claim 1, characterized in that: High temperature conditions are provided by an artificial climate incubator.

4. The method for breeding cowpea for high temperature resistance during flowering and pod stage according to claim 1, characterized in that: The dosage of stress agent was 0.15 g / kg soil.

5. The method for breeding cowpea for high temperature resistance during flowering and pod stage according to claim 1, characterized in that: Also includes: During the flowering and pod stage after transplanting, adjust the ambient temperature to 35℃~40℃.

6. The method for breeding cowpea for high temperature resistance during flowering and pod stage according to claim 1, characterized in that: The seeds of each hybrid generation are subjected to high temperature stress before transplanting to select plants that are resistant to high temperatures.

7. The use of a stress agent in cultivating high temperature resistant cowpea plants during the flowering and pod stage, characterized in that: The stress agent is the stress agent according to claim 1.

8. The use according to claim 7, characterized in that: The application comprises cultivating cowpea plants which can tolerate 35°C to 45°C during the flowering and podning period.

9. The use according to claim 8, characterized in that: The application also includes improving the quality of long beans.

10. The use according to claim 9, characterized in that: The method for improving the quality of cowpea includes improving the protein content, vitamin C content, total sugar content and yield.

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