Breeding method of feed quinoa variety in saline-alkali soil

Abstract

A breeding method of a feed quinoa variety in saline-alkali soil relates to the technical field of quinoa breeding and comprises four steps of female parent and male parent selection, cultivation, backcross and selfing. Appropriate female parents and male parents are selected as parents, BC3Fn-generation quinoa is obtained through three times of backcross and n times of selfing, in the process, saline-alkali soil is subjected to manual intervention treatment through the steps S21 to S26, planting management is conducted on each generation of quinoa, and the yield, the protein content and the plant height of the cultivated BC3Fn-generation quinoa whole plant can reach the optimum. The protein content of the BC3Fn generation chenopodium quinoa whole plant meets the requirement, and it is proved that the BC3Fn generation chenopodium quinoa whole plant can serve as high-protein forage grass to meet the nutritional requirement of livestock, so that the variety of feed chenopodium quinoa is increased, and the variety of salt-alkali-tolerant chenopodium quinoa is enriched The yield and plant height of the whole plant of the quinoa of the BC3Fn generation also meet the requirements, which proves that the obtained feed quinoa variety can stably survive in the saline-alkali soil, the problem of improvement and utilization of the saline-alkali soil is solved, and the economic benefit is remarkably increased.

Description

Technical Field

[0001] This invention relates to the field of quinoa breeding technology, specifically to a breeding method for quinoa varieties suitable for saline-alkali land for forage. Background Technology

[0002] Quinoa, belonging to the genus *Chenopodium* of the family Chenopodiaceae, is highly adaptable and possesses a certain degree of drought, cold, and salinity tolerance, enabling it to survive in saline-alkali soils. Traditional quinoa varieties primarily produce grains, but in saline-alkali soils, quinoa grain yields are low and its resistance to adverse conditions is weak, resulting in limited variety availability. Furthermore, saline-alkali land resources are currently severely underutilized, and traditional forage plants (such as alfalfa) struggle to survive stably in various types of saline-alkali soils. Summary of the Invention

[0003] In view of this, it is necessary to provide a breeding method for a quinoa variety suitable for saline-alkali land, in which the entire quinoa plant can meet the requirements for forage and can survive stably in saline-alkali land, while solving the problems of single quinoa varieties and serious underutilization of saline-alkali land resources.

[0004] A breeding method for a quinoa variety suitable for saline-alkali land feed includes the following steps:

[0005] S1. Select the drought-resistant quinoa germplasm P1 from the plains as the female parent and the salt-tolerant quinoa germplasm P2 from Peru as the male parent to cross them and obtain the F1 generation of quinoa.

[0006] S2. Cultivation of F1 generation quinoa, as detailed below:

[0007] S21. Select saline-alkali land as cultivation site;

[0008] S22. Pretreatment of saline-alkali land: Deeply plow the saline-alkali land to a depth of 40cm-50cm, with a ridge height of 15cm. In the early stage, add 0.2t of gypsum powder, 0.3t of decomposed straw and 0.3t of fermented quinoa straw per mu. In the later stage, apply 2t of desulfurized gypsum and 10t of decomposed cow manure per hectare to obtain the pretreated saline-alkali land.

[0009] S23. Sow seeds on pretreated saline-alkali land;

[0010] S24. During the seedling stage of quinoa, the irrigation amount is 20m³ per mu. 3 ~50m 3 Apply 30 kg of nitrogen and 15 kg of phosphorus pentoxide compound fertilizer per hectare. During the rapid growth period of quinoa, irrigate 30 m³ per mu. 3 ~60m 3 During the initial stage of rapid growth, apply compound fertilizer of 60 kg nitrogen and 45 kg potassium oxide per hectare. During the middle and later stages of rapid growth, supplement with 20 kg nitrogen and 30 kg potassium oxide per hectare. In the final stage of rapid growth, supplement with 200 g to 500 g chelated zinc fertilizer per hectare. After harvesting quinoa, irrigate 15 m³ per hectare.3 ~40m 3 Compound fertilizer containing seaweed extract and humic acid foliar fertilizer;

[0011] S25. Harvest the quinoa at the designated time.

[0012] S26. Quinoa germplasm is obtained when the quinoa growth cycle ends and the quinoa enters the reproductive period.

[0013] S3. Using F1 generation quinoa germplasm as the male parent, backcross with the female parent P1 in the parent line. After three generations of backcrossing, BC3F1 generation quinoa is obtained. Each generation of quinoa in the backcross is cultivated through steps S21 to S26.

[0014] S4. The BC3F1 generation quinoa was cultivated and self-pollinated through steps S21-S26. The yield, protein content, and plant height of each generation of quinoa obtained from self-pollination were measured until the nth generation BC3F1 was obtained. n After the yield, protein content, and plant height of the whole quinoa plant met the requirements, BC3F was obtained. n Quinoa seeds.

[0015] Preferably, in step S23, the seeding amount per mu of saline-alkali land is 0.5 kg, the row spacing is 40 cm to 60 cm, and the plant spacing is 20 cm to 30 cm; in step S24, a drip irrigation pipe is laid between every two rows of seeds, and high-frequency and low-frequency alternating drip irrigation is carried out, with a dripper flow rate of 1.2 L / h and a spacing of 30 cm. The irrigation water is magnetized so that its EC value decreases by <5% and its pH value decreases by 0.1 to 0.3.

[0016] Preferably, in step S24, irrigation is carried out at different stages of quinoa when the soil EC value is ≥6dS / m, and calcium ammonium nitrate is added during irrigation using a drip irrigation and fertilization system.

[0017] Preferably, in step S25, the quinoa is first harvested 60 to 80 days after sowing and when the plant height is 80 cm to 90 cm, leaving a stubble height of ≥15 cm. The number of harvests per year is 3 to 4. Seaweed extract is sprayed within 24 hours after each harvest, and the seaweed extract contains 0.05% alginate oligosaccharide.

[0018] Preferably, in step S3, backcrossing generation 1 yields BC1F1 generation quinoa. In backcrossing generation 2, the BC1F1 generation quinoa germplasm is used as the male parent and backcrossed with the female parent P1 to obtain BC2F1 generation quinoa. In backcrossing generation 3, the BC2F1 generation quinoa germplasm is used as the male parent and backcrossed with the female parent P1 to obtain BC3F1 generation quinoa.

[0019] Preferably, in step S4, the data requirements are as follows: the yield of the whole quinoa plant is 3.5t / mu to 4.5t / mu, the protein content is 18% to 23%, and the plant height is greater than 180cm.

[0020] Preferably, step S5 is included after step S4, for BC3F n Stability testing of quinoa substitute: BC3F was tested in steps S21-S26. n Quinoa was cultivated continuously for m years, with BC3F being harvested annually. n The yield, protein content, and plant height of the whole quinoa plant were measured. If the variation range of these data within m years met the requirements, then BC3F was determined. n The quinoa variety was stabilized and used as a novel forage quinoa variety, and its seeds were obtained; if the variation range of this data within m years does not meet the requirements, then the study on BC3F will continue. n Quinoa was self-pollinated to obtain BC3F. n+1 Replace with quinoa and repeat step S5.

[0021] Preferably, in step S5, the stability requirement is specifically met as follows: the yield of the whole quinoa plant varies by less than 3% within m years, and the variations in protein content and plant height are both less than 5% within m years.

[0022] Preferably, in step S5, m ≥ 4.

[0023] The present invention adopts the above-mentioned technical solution, and its beneficial effects are as follows: by selecting suitable maternal and paternal parents as parents, BC3F is obtained through 3 backcrosses and n selfcrosses. n Quinoa was used as a second-generation crop, and during this process, artificial intervention was carried out on the saline-alkali land through steps S21 to S26, and planting management was carried out for each generation of quinoa to cultivate BC3F. n The yield, protein content, and plant height of quinoa were optimized. BC3F n The protein content of the whole quinoa plant meets the requirements, proving that it can be used as a high-protein forage to meet the nutritional needs of livestock. This increases the variety of quinoa for feed, solves the problem of low grain yield and low economic benefits of traditional quinoa varieties in saline-alkali land, and enriches the multi-purpose range of salt-tolerant quinoa varieties. BC3F n The yield and height of the whole quinoa plant also meet the requirements, proving that the obtained quinoa variety for feed can survive stably in saline-alkali land, solving the problem of saline-alkali land resource improvement and utilization, and significantly increasing economic benefits. Detailed Implementation

[0024] The technical solutions and effects of the embodiments of the present invention will be further described in detail below.

[0025] The embodiment of the present application provides a breeding method of a salt and alkali land forage quinoa variety, comprising the following steps:

[0026] S1, selecting plain drought-tolerant quinoa germplasm P1 as a female parent and Peruvian salt-tolerant quinoa germplasm P2 as a male parent to perform hybridization, and obtaining F1 generation quinoa;

[0027] S2, cultivating the F1 generation quinoa, and the cultivation specifically comprises the following steps:

[0028] S21, selecting a salt and alkali land as a cultivation land;

[0029] S22, pretreating the salt and alkali land: deep ploughing the salt and alkali land to a depth of 40cm-50cm, and forming a ridge with a height of 15cm; in an early stage, adding 0.2t of gypsum powder, 0.3t of rotten straw and 0.3t of quinoa fermented straw per mu of land; in a later stage, adding 2t of desulfurized gypsum and 10t of rotten cow dung per hectare of land, to obtain the pretreated salt and alkali land;

[0030] S23, sowing seeds on the pretreated salt and alkali land: the sowing amount of seeds per mu of the salt and alkali land is 0.5kg, the sowing row distance is 40cm-60cm, and the plant distance is 20cm-30cm;

[0031] S24, in a seedling stage of the quinoa, irrigating 20m 3 -50m 3 per mu of land, and applying 30kg of nitrogen and 15kg of diaphthorine per hectare of land; in a rapid growth stage of the quinoa, irrigating 30m 3 -60m 3 per mu of land, applying 60kg of nitrogen and 45kg of potassium oxide per hectare of land in an early stage of the rapid growth stage, supplementally applying 20kg of nitrogen and 30kg of potassium oxide per hectare of land in a middle and late stage of the rapid growth stage, and supplementally applying 200g-500g of chelated zinc fertilizer per hectare of land in a late stage of the rapid growth stage; after the quinoa is cut, irrigating 15m 3 -40m 3 per mu of land, and applying a compound fertilizer of seaweed extract and humic acid foliar fertilizer; wherein, when the EC value of soil is greater than or equal to 6dS / m in different stages of the quinoa, irrigation is performed, and a drip irrigation and fertilization integrated mode is used, and calcium nitrate is added during irrigation; the irrigation mode is that a drip irrigation pipe is laid between every two rows of seeds, high-frequency and low-frequency drip irrigation is alternately performed, the flow rate of a drip head is 1.2L / h, the interval is 30cm, the irrigation water is magnetized, and the decrease amplitude of the EC value is less than 5%, and the pH value decreases by 0.1-0.3;

[0032] S25, cutting the quinoa at a predetermined time: the quinoa is cut for the first time when the quinoa is sowed for 60 days-80 days and the plant height is 80cm-90cm, the stubble height is greater than or equal to 15cm, the cutting frequency is 3-4 times per year, and seaweed extract is sprayed within 24 hours after each cutting, and the content of the seaweed oligosaccharide in the seaweed extract is 0.05%.

[0033] S26, obtaining the quinoa germplasm when the quinoa enters the propagation period at the end of the growth cycle;

[0034] S3, using the F1 generation quinoa germplasm as the male parent to perform the first generation backcross with the female parent P1 in the parent to obtain the BC1F1 generation quinoa, selecting the excellent single plant germplasm of the BC1F1 generation quinoa as the male parent to perform the second generation backcross with the female parent P1 in the parent to obtain the BC2F1 generation quinoa, selecting the salt-tolerant and drought-resistant single plant germplasm of the BC2F1 generation quinoa as the male parent to perform the third generation backcross with the female parent P1 in the parent to obtain the BC3F1 generation quinoa; wherein each generation of quinoa in the backcross is cultivated through steps S21-S26;

[0035] S4, cultivating the BC3F1 generation quinoa through steps S21-S26 and selfing, detecting the yield, protein content and plant height data of each generation of quinoa whole plant obtained by selfing until the nth generation BC3F1 generation quinoa is obtained, wherein the yield of the quinoa whole plant is 3.5-4.5 t / mu, the protein content is 18-23%, and the plant height is greater than 180 cm; n

[0036] S5, performing stability detection on the BC3F1 generation quinoa: cultivating the BC3F1 generation quinoa through steps S21-S26, continuously cultivating for m years, m≥4, detecting the yield, protein content and plant height data of the BC3F1 generation quinoa whole plant each year, if the data change range within m years meets the requirements, i.e. the yield of the quinoa whole plant changes by less than 3% within m years, the protein content change range and the plant height change range within m years are both less than 5%, then the BC3F1 generation quinoa is determined to be stable, and it is used as a new type of forage quinoa variety, and its seeds are obtained; if the data change range within m years does not meet the requirements, then the BC3F1 generation quinoa is selfed to obtain the BC3F1 generation quinoa, and step S5 is repeated. n n n n n n+1

[0037] The female parent is selected as LQ-17, which has a drought-tolerant gene, and the male parent is selected as SalT-9, which has a salt-tolerant gene, the F1 generation quinoa obtained by hybridization can inherit the drought-tolerant and salt-tolerant genes, so as to survive in the saline-alkali land with high salt content and drought, to ensure that the backcross and selfed offspring can adapt to the saline-alkali land and fully utilize the saline-alkali land resources; and in the backcross and selfing process, each generation of quinoa is cultivated through steps S21-S26, so that the cultivated BC3F1 generation quinoa is stable. n ​​​​​​​The yield, protein content and plant height of the whole plant of the selected salt-tolerant wild buckwheat reach the optimum, and the optimal protein content can make it as a high-quality forage grass to meet the nutritional needs of livestock, thereby increasing the variety of buckwheat; the optimal yield and plant height can ensure that the selected buckwheat has the ability to survive stably in saline-alkali land, thereby reducing the hindrance of saline-alkali land to the survival of buckwheat.

[0038] The new forage buckwheat variety obtained by the breeding method has thick stems and strong branching, and the surface is covered with a wax layer to reduce water evaporation. The plant height of the whole plant at the mature stage is 180 cm to 230 cm, the leaf shape is rhombus to oval, the surface is covered with a wax layer, the main root depth is ≥1.5 m, the dry weight of the whole plant has a crude protein content of 16% to 23%, a crude fiber content of ≤25% to 30%, and a sulfur amino acid content of ≥0.44% to 1.63%. The palatability is better than that of traditional forage grasses such as alfalfa and corn silage, and the whole plant can be used as high-protein forage grass with high feeding value. The new forage buckwheat variety has strong drought resistance, specifically, the root system is developed, the main root depth is 1.5 m, the lateral roots are dense, and the leaf stomatal regulation ability is strong, and it can still maintain growth when the soil water content is less than 10%. The new forage buckwheat variety has strong salt-tolerance, and can complete the life cycle under the condition that the soil EC value is ≤8 dS / m and the pH value is 8.5 to 9.5. The salt-tolerance mechanism includes ion compartmentalization and synthesis of osmoregulatory substances such as betaine, and the ion compartmentalization is manifested as sodium ion accumulation in the vacuole. The period from sowing to maturity is 110 days to 120 days, and the maturity is defined as the maturation of buckwheat seeds.

[0039] In step S21, the selected saline-alkali land is located in the north of Yinchuan, Ningxia Hui Autonomous Region, i.e. the north of Ningxia Plain, north latitude 38° to 39°, east longitude 106° to 107°. The saline-alkali land accounts for more than 30% in this area, which is the most serious saline-alkali agricultural area in Ningxia. The saline-alkali land contains gray calcareous soil and alluvial soil formed by the Yellow River. The area belongs to a temperate continental climate, with annual precipitation ≤200 mm, evaporation ≥2000 mm, and frost-free period of 150 to 160 days. The saline-alkali type of the saline-alkali land is sulfate-chloride type, i.e. the proportion of sulfate and chloride in the soil is more than 60%; the surface soil (0 cm to 20 cm) EC value is 5 dS / m to 15 dS / m, the pH value is 9.0 to 10.2, the sodium adsorption ratio is ≥13, the percentage of exchangeable sodium is ≥15%, the organic matter content is <0.6%, the available phosphorus is ≤5 mg / kg, and the available potassium is low; the soil is seriously salted in spring and autumn, and the thickness of the salt crust on the ground surface in spring is 1 cm to 2 cm. The survival rate of crop planting is low, and the idle is more serious.

[0040] In step S22, since the saline-alkali soil selected in step S21 has poor permeability, the thickness of the salt crust on the ground surface in spring can reach 1-2 cm, and therefore, the saline-alkali soil needs to be pretreated, which specifically includes: first, physically improving the saline-alkali soil: deep plowing the saline-alkali soil by 40-50 cm and sowing in micro-ridge ditches with a ridge height of 15 cm, which is used to break the salt crust, reduce the salt concentration in the surface layer, and the ridge and ditch structure can make the subsequent irrigation water directional infiltrate, leaching sodium ions and chloride ions to the lower layer of the root system, i.e., below 40 cm. Second, chemically improving the saline-alkali soil: adding 0.2 t of gypsum powder, 0.3 t of decomposed straw, and 0.3 t of fermented straw of chenopodium album per mu of land in the early stage, the gypsum powder is pure anhydrous calcium sulfate, which is used to quickly reduce alkalinity, provide high-concentration calcium ions, quickly replace sodium ions, generate calcium sulfate dihydrate, reduce the percentage of exchangeable sodium, and the decomposed straw and fermented straw of chenopodium album can increase organic matter and improve the permeability of the surface soil; in the later stage, adding 2 t of desulfurized gypsum and 10 t of decomposed cow dung per hectare, the desulfurized gypsum contains gypsum and sulfur elements, which is used to reduce salt for a long time, continuously provide calcium, and promote the subsequent leaching of salt, and the decomposed cow dung is used to fertilize the soil, provide more than 30% of stable organic matter and microbial community, and the calcium ions in the decomposed cow dung and the desulfurized gypsum synergistically promote the formation of soil aggregates, which can repair the aggregate structure and increase the porosity by 20-30%. Third, biologically improving the saline-alkali soil: inoculating salt-tolerant bacteria before sowing, such as pseudomonas putida, which is used to activate phosphorus and potassium in the soil, inhibit pathogenic bacteria, and the salt-tolerant bacteria group secretes ACC deaminase to reduce the ethylene stress of chenopodium album seedlings.

[0041] The pretreated and untreated saline-alkali soils are compared, and the data are as follows:

[0042] Comparison of soil index data:

[0043] Untreated soil Treated soil Difference rate EC value of soil surface (0-20 cm) 12.3 dS / m 6.8 dS / m -44.7％ Percentage of exchangeable sodium 18.5％ 9.2％ -50.3％

[0044] Comparison of yield data:

[0045] Untreated soil Treated soil Difference rate Emergence rate (15 days after sowing) 42％ 78％ +85.7％ Fresh weight of first cutting 4.1 t / ha 7.3 t / ha +78.0％ Grain yield during whole growth period 850 kg / ha 1520 kg / ha +78.8％

[0046] Comparison of quality index data:

[0047] Untreated soil Treated soil Difference rate Dry stem crude protein content 10.2％ 16.8％ +35.3％ Leaf sodium ion accumulation 3.8 mg / g 1.6 mg / g -57.9％ Root activity: TTC reduction amount 45.6 μg / g x h 82.3 μg / g x h +80.5％

[0048] Therefore, the pretreatment of the saline-alkali soil in step S22 is an essential step, which can solve the core obstacles of the saline-alkali soil. First, the problem of salt accumulation is solved. In the 7 days after sowing, the salt crust on the surface of the soil without pretreatment leads to 50% of the seed of the chenopodium album failing to germinate, while the soil after pretreatment can ensure the chenopodium album seed to germinate successfully because the salt crust has been broken. Second, the problem of sodium toxicity is solved. In the soil without pretreatment, the ratio of sodium ions to potassium ions in the leaves of seedlings reaches 2.5, which significantly affects photosynthesis, while in the soil after pretreatment, the ratio of sodium ions to potassium ions in the leaves of seedlings is 0.7-0.8, which reduces sodium ions and avoids the influence on photosynthesis. Third, the specificity of the F1 generation of chenopodium album and its backcross and self-crossed offspring can be met. The F1 generation of chenopodium album and its backcross and self-crossed offspring are weak in salt tolerance at the seedling stage, that is, the salt-sensitive period is 0-30 days, and the pretreatment can increase the critical salt tolerance EC value from 6 dS / m to 9 dS / m. Fourth, the depth of the main root of chenopodium album is increased. The depth of the main root of chenopodium album planted in the soil without pretreatment is 0.7 m, while the deep ploughing step in the pretreatment can promote the main root of chenopodium album to penetrate to 1.2-1.5 m, so that the main root of chenopodium album can fully utilize the low-salt water in the deep soil.

[0049] In step S24, first, for the fertilizer, the type and quality of the fertilizer are specially selected, first, in the traditional quinoa planting fertilizer, the base fertilizer adopts balanced compound fertilizer, for example, 15-15-15, and the amount is large, the nitrogen content is 60kg / ha-80kg / ha, and the problem of phosphorus fixation and potassium loss in saline-alkali soil is ignored. However, in the present application, due to the demand of F1 generation quinoa and its backcross and selfed progeny quinoa, the root system needs to be established quickly at the seedling stage to cope with salt stress, and excessive nitrogen will inhibit root growth, therefore, the fertilizer applied at the seedling stage of quinoa is nitrogen 30kg and diaphosphorus 15kg, which is used as base fertilizer, the amount of nitrogen is reduced, and the amount of phosphorus is increased, and humic acid chelated phosphorus fertilizer is added, 3kg of humic acid per hectare is applied with phosphorus fertilizer, the calcium ion is complexed to reduce phosphorus fixation, and the measured available phosphorus is increased by 18%. F1 generation quinoa and its backcross and selfed progeny quinoa have weak salt tolerance at the seedling stage, therefore, the seedling fertilizer needs to have the function of promoting the development of quinoa root system, humic acid can inhibit soil phosphorus fixation and improve phosphorus utilization rate by more than 20%, diaphosphorus in the seedling fertilizer is applied in the form of ammonium polyphosphate, and the solubility is 50% higher than that of superphosphate at pH>9. Second, in the traditional quinoa planting fertilizer, the topdressing is mainly urea, and there is lack of stage nutrition regulation, which is easy to cause late lodging or insufficient grain filling. In the present application, during the rapid growth period of quinoa, that is, during the jointing period, the fertilizer is applied as topdressing, at the early jointing stage, quinoa needs nitrogen to promote stem and leaf growth, and needs potassium to promote preliminary reproductive development, at this time, 60kg of nitrogen and 45kg of potassium oxide are applied per hectare, the ratio of nitrogen to potassium is 4:3, the nitrogen is slightly higher than the potassium, which can balance the nutrition and stress resistance, at the middle and late jointing stage, with the rapid elongation of stem and stalk, the potassium fertilizer needs to be increased, at this time, 20kg of nitrogen and 30kg of potassium oxide are supplemented per hectare, the ratio of nitrogen to potassium is 1:1.5, the high potassium ratio is used for: (1) to improve the resistance to lodging, potassium can strengthen the cell wall and increase the strength of the stem and stalk; (2) to promote sugar transport, potassium promotes the transport of photosynthetic products to the ear, laying the foundation for subsequent ear differentiation; (3) to promote water regulation, potassium optimizes the opening and closing of stomata to cope with the high temperature stress that may occur during the jointing period. The total amount of potassium applied during the whole jointing period reaches 75kg, which is closer to the peak demand of F1 generation quinoa and its backcross and selfed progeny quinoa. In addition, nitric acid calcium ammonium is added in the way of drip irrigation water and fertilizer integration, which can be used to replace urea, nitrate in nitric acid calcium ammonium is preferentially absorbed by quinoa than chlorine ion in soil, avoiding chlorine poisoning in saline-alkali soil, the selectivity of potassium ion and sodium ion absorption of F1 generation quinoa and its backcross and selfed progeny quinoa is ≥5 at the middle and late jointing stage, that is, the demand for potassium ion increases suddenly, high potassium combined with nitric acid calcium ammonium, 45kg of potassium oxide is applied per hectare, which can maintain the cell osmotic balance, calcium ion in nitric acid calcium ammonium can repair salt injury cell membrane, at the same time, ammonium ion in nitric acid calcium ammonium is not easy to volatilize in saline-alkali soil.Thirdly, in the traditional quinoa planting fertilizer, the foliar fertilizer does not add organic active substances, which is difficult to alleviate salt stress; and in the present application, after the quinoa is cut, it is in the regeneration period, and 0.1% seaweed element and 0.5% humic acid foliar spraying are used, the seaweed element is an organic active substance, which contains brown algae oligosaccharide, can activate the salt-tolerant gene in F1 generation quinoa and its backcross and selfed progeny quinoa, promote axillary bud regeneration, and shorten the interval of secondary cutting by 5-7 days. The seaweed element and the humic acid foliar fertilizer produce a synergistic effect, the seaweed element also contains mannuronic acid, induces F1 generation quinoa and its backcross and selfed progeny quinoa to synthesize betaine, compared with the quinoa obtained by traditional fertilizer application, the betaine content of the quinoa obtained by the fertilizer application of the present application increases by 35%, the humic acid small molecules directly penetrate the stomata, improve the stability of chlorophyll, that is, the SPAD value increases by 15%, wherein the small molecules in the humic acid small molecules refer to the weight average molecular weight less than 1000 Da.

[0050] The F1 generation quinoa and its backcross and selfed progeny quinoa or any generation quinoa thereof are cultivated in the same saline-alkali soil, and the traditional fertilizer and the fertilizer of the present application are applied for comparison, and the data are as follows:

[0051] Traditional fertilizer Fertilizer of the present application Difference rate Plant height at seedling stage (30 days) 18.5 cm 24.2 cm +30.8％ Fresh weight of first cutting 5.2 t / ha 7.1 t / ha +36.5％ Sodium ion content in stem (dry weight) 0.45％ 0.28％ -37.8％ Fresh weight of second cutting 3.8 t / ha 5.3 t / ha +39.5％

[0052] Therefore, the quinoa fertilized by the fertilizer of the present application has higher plant height at the seedling stage, greater fresh weight per hectare after the first cutting and the second cutting, and less sodium ion content in the stem, that is, the quinoa has higher survival rate and faster growth rate, and reduces sodium toxicity.

[0053] Secondly, for irrigation, first, the irrigation method of the present application is improved: the traditional irrigation method uses flooding irrigation or furrow irrigation. The present application uses high-low frequency alternate drip irrigation, which can accurately control the salt leaching of the quinoa root zone. Second, the irrigation water quality of the present application is improved, the traditional irrigation water quality directly uses underground water, and the EC value is 3-4 dS / m. The irrigation water of the present application is subjected to magnetic water treatment, so that the EC value is ≤2 dS / m, and the pH value is adjusted to 6.0-6.5, which can reduce the sodium adsorption ratio of the irrigation water. Third, the irrigation frequency of the present application is improved: the traditional irrigation frequency is fixed cycle irrigation, irrigation once every 7-10 days. The present application triggers irrigation when the soil EC value is ≥6 dS / m, which can dynamically respond to soil salt stress, and the soil EC value can be monitored in real time by instruments or automatically controlled by controllers. Fourth, the present application uses water-fertilizer coupling: in the traditional cultivation process, the fertilizer is applied and then irrigated. The present application uses drip irrigation water and fertilizer integration, increases calcium ammonium nitrate and humic acid liquid fertilizer, which can avoid nitrogen volatilization and phosphorus fixation in saline-alkali soil.

[0054] Furthermore, the water and fertilizer management in step S24 is for F1 generation of quinoa and backcross and self-crossed progeny of quinoa. First, F1 generation of quinoa and backcross and self-crossed progeny of quinoa are sensitive to salt in the seedling stage (0-30 days), and the traditional flooding irrigation method will cause salt accumulation, and the EC value of the ground surface reaches 15 dS / m. However, the present application adopts the method of low-frequency small water volume drip irrigation, specifically 15 m 3 / ha each time, the wetting front depth is 20 cm, which can induce quinoa root to grow downward and avoid the high salt area on the surface of the soil, and the drip irrigation belt is laid in the ridge and furrow, which can take advantage of the salt gradient effect of the ridge, that is, the salt content on the ridge top is 40% higher than that at the bottom of the furrow, which can protect the seedlings. Therefore, compared with the traditional cultivation method, the cultivation method of the present application can increase the root length of F1 generation of quinoa and backcross and self-crossed progeny of quinoa by 50% in the seedling stage, and reduce the ratio of sodium ion to potassium ion to 0.7-0.8. Second, F1 generation of quinoa and backcross and self-crossed progeny of quinoa need a sudden increase in the amount of potassium in the rapid growth period, especially in the middle and late stages of node pulling, but the potassium ion in saline-alkali soil is easily competed by sodium ion, which inhibits the absorption of quinoa. Therefore, the present application uses high-potassium drip irrigation fertilizer, that is, 20 kg of nitrogen and 30 kg of potassium oxide are supplemented per hectare, the ratio of nitrogen to potassium is 1:1.5, and the fertilizer is injected three times, which is combined with the method of pulse drip irrigation, that is, irrigation for 5 minutes and stop for 10 minutes, which can improve the potassium migration rate. 200-500 g of chelated zinc fertilizer is supplemented per hectare after the node pulling stage, the zinc content in the chelated zinc fertilizer is 0.1%, which can alleviate the zinc deficiency under high pH. In the early stage of node pulling, the growth is mainly driven by the rapid growth of stems and leaves, the demand for zinc is relatively stable, and the required amount of zinc is about 50-100 g per hectare, so the original zinc in the soil or the zinc in the base fertilizer can temporarily meet the demand, and therefore, zinc fertilizer is not needed. In the middle and late stages of node pulling, with the start of spike differentiation, the demand for zinc as a co-factor of various enzymes, such as carbonic anhydrase and RNA polymerase, increases suddenly. Therefore, zinc fertilizer is supplemented in the late stage of node pulling, which can promote the synthesis of auxin, prevent the "shortening of internodes" deformity, reduce the risk of incomplete pollen development in the late stage, and enhance the photosynthetic efficiency of leaves as an essential element for chlorophyll synthesis. The potassium content in the stem dry weight of quinoa is increased to 2.8%, and compared with the traditional cultivation method, the lodging rate is reduced from 30% to 5%.

[0055] Step S25 is to treat with seaweed extract and humic acid after mowing, which can increase the regeneration speed by 40%.

[0056] The ordinary quinoa variety is used for traditional flooding irrigation cultivation, F1 generation of quinoa and backcross and self-crossed progeny of quinoa or any generation of quinoa is used for traditional flooding irrigation cultivation, and F1 generation of quinoa and backcross and self-crossed progeny of quinoa or any generation of quinoa is used for the drip irrigation water and fertilizer integrated cultivation of the present application. The other conditions are unchanged, and the data are as follows:

[0057]

[0058]

[0059] Therefore, compared with the ordinary quinoa variety + traditional flooding irrigation and the F1 generation of quinoa and its backcross and self-crossed offspring or any generation of quinoa + traditional flooding irrigation, the F1 generation of quinoa and its backcross and self-crossed offspring or any generation of quinoa combined with the water and fertilizer integrated cultivation method of the present application has the highest water use efficiency and grain yield, saves water resources while having high yield; the water consumption and forage grass sodium ion content in the whole growth period are the lowest, saving water resources while reducing sodium toxicity.

[0060] The new forage quinoa variety of the present application (referred to as "quinoa" in this paragraph and the next paragraph) has a water use rate of 9.8 kg / m 3 ~ 13.6 kg / m 3 , which is 2.1 times that of alfalfa, which is also used as forage. The reason is as follows: first, the biomass output per unit of water of quinoa is higher. Quinoa can produce 9.8 kg ~ 13.6 kg of dry matter, including grains and stems and leaves, per 1 m 3 of water consumed, while alfalfa can only produce 4.0 kg ~ 6.5 kg, which means that quinoa can provide more forage output under the same water amount. The water use rate of quinoa under drip irrigation conditions is 0.649 kg / m 3 , while that of alfalfa under similar conditions is usually only 0.25 kg / m 3 ~ 0.35 kg / m 3 . Second, the irrigation requirement of quinoa is lower. Quinoa can be irrigated only 1350 m 3 / ha in the whole growth period, while alfalfa usually needs 3000 m 3 / ha ~ 4500 m 3 / ha, but the yield of quinoa can reach 70% ~ 80% of that of alfalfa. In the northwest arid region within the scope of the saline-alkali land described in step (2) of the present application, quinoa can still maintain a high yield even under deficit irrigation of 2250 m 3 / ha ~ 3675 m 3 / ha, while the yield of alfalfa will decrease significantly under the same conditions. Third, quinoa has stronger stress adaptation ability. Quinoa can still maintain a high water use rate under the conditions of an EC value of 8 dS / m of saline-alkali land and less than 200 mm of precipitation, while the water use rate of alfalfa will decrease significantly under saline-alkali stress. For example, in the Yinbei saline-alkali land within the scope of the saline-alkali land described in step (2) of the present application, the water use rate of quinoa is 1.5 times that of alfalfa, and the sodium ion accumulation amount is lower.

[0061] The reason for the difference in water use efficiency between quinoa and alfalfa is two-fold. First, the internal factors, physiological mechanisms are different, quinoa structure is more optimal, quinoa has a taproot that can reach 1.5m deep root system, which can absorb deep soil moisture, while alfalfa has only 0.6m-1.0m shallow root system, which depends on surface water. The stomatal regulation ability is different, quinoa will reduce the stomatal opening and reduce transpiration in drought, while the stomatal regulation of alfalfa is weak, and the water loss is larger. The accumulation of osmotic adjustment substances is different, quinoa can synthesize betaine, proline and other substances to maintain cell water balance, while the osmotic adjustment ability of alfalfa is weaker. The photosynthetic efficiency is different, under the same water condition, the photosynthetic rate of quinoa is 20%-30% higher than that of alfalfa, and the water use efficiency is higher. Second, the external factors, cultivation management is different, quinoa uses low frequency and small water volume drip irrigation to reduce evaporation loss, while alfalfa traditionally relies on flooding and sprinkling irrigation, which has low water use efficiency. The adaptability to saline-alkali land is different, quinoa has stronger adaptability to saline-alkali land, which reduces salt damage through sodium ion efflux mechanism, while alfalfa is easily inhibited by salt. Quinoa can effectively use precipitation during the growth period, and the growth period reaches 110-120 days to maturity, which can avoid the peak of drought, while alfalfa needs 150-180 days to mature, which needs more water.

[0062] The data of the new forage quinoa variety and alfalfa are as follows:

[0063]

[0064] Therefore, the high water use efficiency of the new forage quinoa variety is mainly due to the deep root system, stomatal regulation, osmotic adaptation and optimized irrigation management, which can still maintain high yield in drought and saline-alkali environment. In contrast, the water use efficiency of alfalfa is low, which is mainly limited by shallow root system, high transpiration and salt sensitivity. Therefore, in water resource scarce areas, such as saline-alkali land in step S21 of the present application, the new forage quinoa variety is a more sustainable forage crop selection than alfalfa.

[0065] In step S25, first, the cutting time of the present application is improved: the cutting time of traditional quinoa cultivation is once after the grain matures, which leads to less forage use. The present application adopts a double cutting mode, and the first cutting is at a plant height of 80cm with a stubble of 15cm. Second, the wound treatment after cutting is improved: traditional quinoa cultivation has no special treatment after cutting, which heals naturally. The present application sprays seaweed within 24 hours after cutting, wherein the content of alginate oligosaccharide is 0.05%. Third, the water and fertilizer management is improved: traditional quinoa cultivation stops irrigation and fertilization after cutting. The present application uses large water to rinse salt 80m 3Fourthly, the present application improves the regulation of the regeneration period: the traditional cultivation of buckwheat relies on natural conditions for regeneration after mowing. However, the present application can inhibit salt return by supplementing salt-tolerant green manure, such as Tianjing, after mowing.

[0066] The ordinary buckwheat variety is selected to use the above-mentioned traditional mowing treatment, and the F1 generation buckwheat and its backcross and self-crossed offspring buckwheat or any generation buckwheat thereof is selected to use the mowing treatment in step S25 of the present application for comparison, and other conditions remain unchanged. The traditional mowing treatment does not have a second mowing step. In order to compare with the double-mowing mode of the present application, the ordinary buckwheat variety is simulated to be mowed for the second time at the same time interval after the first mowing of the F1 generation buckwheat and its backcross and self-crossed offspring buckwheat or any generation buckwheat thereof. The data are as follows:

[0067]

[0068] Therefore, compared with the ordinary buckwheat variety + traditional mowing treatment, the F1 generation buckwheat and its backcross and self-crossed offspring buckwheat or any generation buckwheat thereof obtained by using the mowing method of the present application has increased second-mowing yield and total yield, reduced sodium ion content, reduced sodium toxicity, and reduced salt damage risk. The ordinary buckwheat variety has weak regeneration ability, and the untreated wound after the first mowing leads to infection and nutrient loss, resulting in a regeneration rate of <30% and low biomass accumulation. The ordinary buckwheat variety that is not treated with large water salt leaching has high salt stress due to stopping irrigation and fertilization, and severe salt damage leads to seedling death, resulting in a high failure rate of 60% for the second mowing. However, the F1 generation buckwheat and its backcross and self-crossed offspring buckwheat or any generation buckwheat thereof has a regeneration rate of more than 75% after the first mowing.

[0069] The ordinary buckwheat variety is selected to be treated with haie and humic acid after mowing, and the F1 generation buckwheat and its backcross and self-crossed offspring buckwheat or any generation buckwheat thereof is selected to be treated with haie and humic acid after mowing for comparison. The data are as follows:

[0070]

[0071]

[0072] Therefore, compared with F1 generation of quinoa and its backcross and self-crossed progeny of quinoa or any generation of quinoa, the common quinoa variety has weak regenerative response, which is caused by: first, genetic potential difference, axillary bud differentiation ability difference, F1 generation of quinoa and its backcross and self-crossed progeny of quinoa or any generation of quinoa has 3-4 active axillary buds per node, and the common quinoa variety has only 1-2, and the expression amount of cytokinin receptor gene of dormant bud of F1 generation of quinoa and its backcross and self-crossed progeny of quinoa or any generation of quinoa is 2 times higher, which is more easily activated by seaweed element. Wound response mechanism is different, the jasmonic acid signal pathway of F1 generation of quinoa and its backcross and self-crossed progeny of quinoa or any generation of quinoa is sensitive to alginate oligosaccharide in seaweed element, and the wound healing related enzyme activity of F1 generation of quinoa and its backcross and self-crossed progeny of quinoa or any generation of quinoa is increased by 3 times, such as polyphenol oxidase, and the common quinoa variety is only increased by 0.8 times. Second, the adaptability of saline-alkali land is limited, and the ion balance ability is different, the sodium ion of the common quinoa variety invades the wound rapidly after cutting, and the sodium ion concentration of the leaf is increased from 0.3% to 0.7% within 24 hours, and the humic acid has an induction efficiency of 30% of the sodium ion efflux gene of F1 generation of quinoa and its backcross and self-crossed progeny of quinoa or any generation of quinoa. The synthesis of osmotic regulation substances is different, because F1 generation of quinoa and its backcross and self-crossed progeny of quinoa or any generation of quinoa contains high-activity CqBADH(betaine synthesis) gene, therefore, the efficiency of seaweed element stimulating F1 generation of quinoa and its backcross and self-crossed progeny of quinoa or any generation of quinoa to synthesize betaine is 5 times that of the common quinoa variety, and betaine is a key osmotic regulation substance. Third, the root system regeneration is difficult, and the root activity of the common quinoa variety is decreased by 40% after cutting due to salt stress, and the superoxide dismutase activity of the root system of F1 generation of quinoa and its backcross and self-crossed progeny of quinoa or any generation of quinoa treated by humic acid can maintain 90% of the original level.

[0073] The common quinoa variety and F1 generation of quinoa and its backcross and self-crossed progeny of quinoa or any generation of quinoa are selected for expression amount change comparison, and the data is as follows:

[0074]

[0075] Therefore, first, the treatment effect of seaweed element and humic acid is highly related to the specific genetic of F1 generation of quinoa and its backcross and self-crossed progeny of quinoa or any generation of quinoa, and the common quinoa variety lacks this genetic basis. Second, seaweed element and humic acid treatment needs to be combined with the drip irrigation water and fertilizer integration and large water salt leaching in the application to control the soil EC value of the quinoa root area to be below 6 dS / m. Third, the promotion effect of seaweed element and humic acid treatment on the regeneration speed is highly dependent on the specific genotype of F1 generation of quinoa and its backcross and self-crossed progeny of quinoa or any generation of quinoa, and the common quinoa variety can only obtain limited effect under the same treatment due to the lack of related genetic mechanism and salt tolerance and adaptability, and this difference highlights the high adaptability of the variety and cultivation method in the application.

[0076] Example 1

[0077] Control group A: using other conventional quinoa varieties and the method of steps S21 to S26 of the present application for cultivation, wherein the soil conditions in step S22 meet pH 8.9-9.5 and salt content 0.53%-0.8%;

[0078] Experimental group A: using F1 generation quinoa and its backcross and self-crossed offspring quinoa or any generation thereof and the method of steps S21 to S26 of the present application for cultivation, wherein the soil conditions in step S22 meet pH 8.9-9.5 and salt content 0.53%-0.8%.

[0079] The experimental results are as follows:

[0080] Control group A Experimental group A Emergence rate 62.7％ 91.2％～98.5％ Fresh grass yield 1.44 t / mu 3.88 t / mu-5.19 t / mu Crude protein content 14.2％ 18.7％～23.4％ Water use efficiency 4.3 kg / m 3 ]]> 9.8 kg / m 3 ~ 13.6 kg / m 3 ]]>

[0081] Therefore, compared with control group A, experimental group A has higher emergence rate and larger fresh grass yield, indicating higher survival rate; experimental group A has higher crude protein content and higher nutritional value for feed; experimental group A has higher water use efficiency and saves more water resources.

[0082] Example 2

[0083] Control group B1: using ordinary quinoa varieties and ordinary cultivation methods for cultivation, wherein traditional fertilizers are used for fertilizers;

[0084] Control group B2: using F1 generation quinoa and its backcross and self-crossed offspring quinoa or any generation thereof and ordinary cultivation methods for cultivation, wherein traditional fertilizers are used for fertilizers;

[0085] Experimental group B: using F1 generation quinoa and its backcross and self-crossed offspring quinoa or any generation thereof and the cultivation method of steps S21 to S26 of the present application for cultivation.

[0086] The experimental results are as follows:

[0087] Control group B1 Control group B2 Experimental group B Emergence rate 35％±3.2％ 48％±4.1％ 82％±5.6％ Fresh weight of first cutting 3.8 t / ha ± 0.4 t / ha 5.2 t / ha ± 0.5 t / ha 8.7 t / ha ± 0.7 t / ha Sodium ion content in stem 4.2 mg / g ± 0.3 mg / g 3.1 mg / g ± 0.2 mg / g 1.4 mg / g ± 0.1 mg / g Crude protein content 9.8％±0.6％ 11.5％±0.8％ 16.3％±0.9％ Root activity (TTC) 38 μg / g x h ± 4.1 μg / g x h 55 μg / g x h ± 5.3 μg / g x h 89 μg / g x h ± 6.8 μg / g x h

[0088] Therefore, compared with control group B1, control group B2 has an increase of 37% in yield, and experimental group B has an additional increase of 67% in yield, proving that the adaptability of F1 generation quinoa and its backcross and self-crossed offspring quinoa requires the cultivation method of the present application.

[0089] Conclusion: the data of control group B1 is poor, ordinary quinoa varieties cannot adapt to saline-alkali land using ordinary cultivation methods. The data of control group B2 is improved compared with the data of control group B1, but the data of experimental group B is overall optimized, therefore, F1 generation quinoa and its backcross and self-crossed progeny quinoa need to be matched with the cultivation method of the present application to better exert the potential. That is to say, F1 generation quinoa and its backcross and self-crossed progeny quinoa combined with the cultivation method of the present application produce effects far exceeding single improvement, realizing synergistic effect, wherein the single improvement is only using F1 generation quinoa and its backcross and self-crossed progeny quinoa using ordinary cultivation methods.

[0090] In step S3, F1 generation quinoa germplasm, BC1F1 generation quinoa germplasm, BC2F1 generation quinoa germplasm and BC3F1 generation quinoa germplasm are all used as the male parent, and there are three reasons, first, core breeding target driving: first, it can strengthen the dominant salt-tolerant traits of the male parent: if the salt tolerance of the male parent P2 is controlled by a dominant nuclear gene (such as SALT), and since the probability of pollen carrying a dominant gene is 50%, using F1 generation quinoa germplasm as the male parent for backcrossing can improve the transmission efficiency of the target gene in the offspring, and since some mitochondrial genes may interfere with the balance of the ratio of sodium ions to potassium ions, using F1 generation quinoa germplasm as the male parent for backcrossing can also avoid the inhibitory effect of the cytoplasmic gene of the female parent on salt tolerance; second, it can avoid the negative effect of the cytoplasm of the female parent: when the cytoplasm of the female parent P1 contains chloroplast protein variants and / or mitochondrial energy metabolism defects (which affect osmoregulation) that conflict with salt tolerance, using F1 generation quinoa germplasm as the male parent for backcrossing can completely replace the healthy cytoplasm of the recurrent parent. Second, molecular genetic mechanism support: first, make genes interact as dominant: the salt-tolerant gene of the male parent P2 may need a specific nuclear background to express, for example, the SALT gene promoter needs to interact with the transcription factor TFIIIA of the female parent P1, and when F1 generation quinoa germplasm is used as the male parent, this interaction pattern is more likely to be retained in the backcross offspring; second, make performance genetic reset: the DNA methylation pattern transmitted by pollen may be more conducive to the de-repression of salt-tolerant genes, and the paternal genome undergoes active demethylation after fertilization, which can eliminate the silencing of salt-tolerant genes by maternal epigenetic markers. Third, special breeding scenario applicability: first, it can quickly introduce dominant single gene traits: if salt tolerance is controlled by a single dominant gene, the gene frequency in each generation of backcrossing when F1 generation quinoa germplasm is used as the female parent and F1 generation quinoa germplasm is used as the male parent is as follows: from the table, the gene frequency of F1 as the male parent is stronger: second, it can overcome cytoplasmic male sterility: if the female parent P1 has a mitochondrial sterility gene, using F1 generation quinoa germplasm as the male parent can avoid the transmission of the sterile trait, ensuring the normal fertility of the backcross offspring.

[0091] Backcross generation [Table 1] Gene frequency (%) of F1 generation quinoa germplasm when used as female parent F1 generation of quinoa germplasm as a father gene frequency (%) BC1F1 50 75 BC2F1 75 87.5 BC3F1 87.5 93.7

[0092] Therefore, selecting the F1 generation of quinoa germplasm as the male parent backcross is a highly targeted technical strategy, which is suitable for the case that the salt tolerance trait is dominant single gene inheritance, the case that the undesirable cytoplasm needs to be replaced quickly, and the case that the target variety is mainly used in high-salt and alkali regions, and is also suitable for the new type of forage quinoa variety obtained by the breeding of the application. Therefore, in step S3, the F1 generation of quinoa germplasm, the BC1F1 generation of quinoa germplasm, the BC2F1 generation of quinoa germplasm and the BC3F1 generation of quinoa germplasm are all used as the male parent.

[0093] In step S4, the BC3F1 generation of quinoa is selfed, and the yield, protein content and plant height data of each generation of quinoa whole plant are detected, and the detection results are as follows:

[0094] BC3F1 generation quinoa BC3F2 generation of buckwheat BC3F3 generation of quinoa BC3F4 generation of quinoa Yield (tons / season / mu) 1～1.5 1.5～2.5 2～3 3.5～5 Protein content (%) 14～16 15～17 16～18 18～23 Plant height (cm) 130～150 155～170 170～180 180～230

[0095] Therefore, after the BC3F1 generation of quinoa is selfed for four generations in step S4, the BC3F4 generation of quinoa that meets the requirements can be obtained, that is, n is 4.

[0096] In step S5, from the first year, the yield, protein content and plant height data of the BC3F4 generation of quinoa whole plant are detected every year for four consecutive years, and the detection results are as follows:

[0097] First year Second year Third year Fourth year Change range Yield (tons / season / mu) 3.5～4 3.6～4.2 3.8～4.5 4.2～5 <3％ Protein content (%) 18.1～20.3 18.1～22.3 18.3～22.5 18.5～23.5 3％～5％ Plant height (cm) 175～180 182～190 185～192 187～230 3％～5％

[0098] Therefore, the stability of the BC3F4 generation of quinoa meets the requirements, and it can be used as the new type of forage quinoa variety cultivated in the application.

[0099] The above disclosure is only the preferred embodiments of the application, and of course cannot limit the scope of the rights of the application. Those skilled in the art can understand that all or part of the processes of the above embodiments can be implemented, and equivalent changes made according to the claims of the application still belong to the scope covered by the application.

Claims

1. A method of breeding a salt-affected land forage quinoa variety, characterized by: Includes the following steps: S1. Select the drought-resistant quinoa germplasm P1 from the plains as the female parent and the salt-tolerant quinoa germplasm P2 from Peru as the male parent to cross them and obtain the F1 generation of quinoa. S2. Cultivation of F1 generation quinoa, as detailed below: S21. Select saline-alkali land as cultivation site; S22. Pretreatment of saline-alkali land: Deeply plow the saline-alkali land to a depth of 40cm~50cm, with a ridge height of 15cm. In the early stage, add 0.2t of gypsum powder, 0.3t of decomposed straw and 0.3t of fermented quinoa straw per mu. In the later stage, apply 2t of desulfurized gypsum and 10t of decomposed cow manure per hectare to obtain the pretreated saline-alkali land. S23. Sow seeds on pretreated saline-alkali land; S24. During the seedling stage of quinoa, irrigate 20m³~50m³ per mu and apply compound fertilizer of 30kg nitrogen and 15kg phosphorus pentoxide per hectare. During the rapid growth period of quinoa, irrigate 30m³~60m³ per mu. In the early stage of the rapid growth period, apply compound fertilizer of 60kg nitrogen and 45kg potassium oxide per hectare. In the middle and late stages of the rapid growth period, supplement with 20kg nitrogen and 30kg potassium oxide per hectare. In the late stage of the rapid growth period, supplement with 200g~500g chelated zinc fertilizer per hectare. After quinoa is harvested, irrigate 15m³~40m³ per mu and apply compound fertilizer of seaweed extract and humic acid foliar fertilizer. S25. Harvest the quinoa at the designated time. S26. Quinoa germplasm is obtained when the quinoa growth cycle ends and the quinoa enters the reproductive period. S3. Use the F1 generation quinoa germplasm as the male parent and backcross it with the female parent P1 in the parent line. After three generations of backcrossing, BC3F1 generation quinoa is obtained. Each generation of quinoa in the backcross is cultivated through steps S21 to S26. S4, BC3F1 generation of quinoa is cultivated by steps S21-S26 and selfed, and the yield, protein content and plant height data of each generation of quinoa whole plant obtained by selfing are detected until the nth generation BC3F n generation of quinoa whole plant meets the requirements, the seed of BC3F n generation of quinoa is obtained.

2. The method of breeding a salt-affected land feed use quinoa variety as claimed in claim 1, wherein: In step S23, the seeding rate is 0.5 kg per mu of saline-alkali land, the row spacing is 40 cm to 60 cm, and the plant spacing is 20 cm to 30 cm. In step S24, a drip irrigation pipe is laid between every two rows of seeds, and high-frequency and low-frequency alternating drip irrigation is used. The dripper flow rate is 1.2 L / h, the spacing is 30 cm, and the irrigation water is magnetized to reduce its EC value by <5% and its pH value by 0.1 to 0.

3.

3. The method of breeding a saline sodic soil feed use quinoa variety as claimed in claim 2, wherein: In step S24, irrigation is carried out at different stages of quinoa when the soil EC value is ≥6dS / m, and drip irrigation with fertigation is used, with calcium ammonium nitrate added during irrigation.

4. The method of breeding a saline sodic soil feeding psuedo-cockle variety as claimed in claim 1, wherein: In step S25, the quinoa is harvested for the first time 60 to 80 days after sowing, when the plant height is 80 cm to 90 cm, leaving a stubble height of ≥15 cm. The number of harvests per year is 3 to 4. Seaweed extract is sprayed within 24 hours after each harvest, and the seaweed extract contains 0.05% alginate oligosaccharide.

5. The method of breeding a saline sodic soil feeding psuedo-cockle variety as claimed in claim 1, wherein: In step S3, backcrossing generation 1 yields BC1F1 generation quinoa. In backcrossing generation 2, the BC1F1 generation quinoa germplasm is used as the male parent and backcrossed with the female parent P1 to obtain BC2F1 generation quinoa. In backcrossing generation 3, the BC2F1 generation quinoa germplasm is used as the male parent and backcrossed with the female parent P1 to obtain BC3F1 generation quinoa.

6. The method of breeding a saline sodic soil feeding psuedo-cockle variety as claimed in claim 1, wherein: In step S4, the data must meet the following requirements: the yield of the whole quinoa plant is 3.5t / mu to 4.5t / mu, the protein content is 18% to 23%, and the plant height is greater than 180cm.

7. The method of breeding a saline sodic soil feeding psuedo-cockle variety as claimed in claim 1, wherein: After step S4, step S5 is further included, that is, the BC3F n Stability detection is performed on the B. chitimskii by steps S21-S26. n The B. chitimskii is cultivated, and the cultivation is continuously performed for m years, and the yield, protein content and plant height of the whole plant of the B. chitimskii are detected every year. n If the change range of the data in m years meets the requirement, it is determined that the B. chitimskii is stable. n The B. chitimskii is used as a new type of forage B. chitimskii variety, and the seed thereof is obtained. n If the change range of the data in m years does not meet the requirement, the B. chitimskii is self-crossed to obtain the BC3F n+1 The B. chitimskii is repeated with step S5.

8. The method of breeding a saline sodic soil feed use quinoa variety as claimed in claim 7, wherein: In step S5, the stability requirements are specifically: the yield of the whole quinoa plant varies by less than 3% within m years, and the variations in protein content and plant height are both less than 5% within m years.

9. The method of breeding a saline sodic soil feed use quinoa variety as claimed in claim 8, wherein: In step S5, m ≥ 4.

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