Method for obtaining distant hybrid offspring of Leymus chinensis and Psathyrostachys chinensis using young embryo rescue technology

Abstract

The invention discloses a method for obtaining Leymus chinensis and New Wheat Straw distant hybridization offspring using young embryo rescue technology, comprising the following steps: 1) hybridization: Leymus chinensis is as female parent, and New Wheat Straw is as male parent; Collect male parent pollen, pollen is pointed on female parent pistil stigma with tweezers for pollination, and immediately bag; 2) disinfection: take hybrid spike after pollination, strip out non-aborted ovary, use volume fraction 75% alcohol to soak 1min, sterile water rinse three times, sodium hypochlorite soak 10min, rear sterile water rinse 5 times; 3) use one-step seedling method or induced callus to expand and multiply, differentiate into seedling method seedling; 4) practice seedling transplanting: when tissue culture seedling grows to 10cm 15cm, ultrapure water is added in culture bottle, after indoor seedling hardening 7d, plant root culture medium is rinsed clean, transplanted into sterilized nutrient soil and cultivated. The present invention has higher young embryo germination rate, induced callus rate and differentiation rate, obtains the hybrid offspring of Leymus chinensis and New Wheat Straw in a relatively short time.

Description

Technical Field

[0001] The invention belongs to the technical field of forage biological breeding, and particularly relates to a method for obtaining distant hybridization offspring of Leymus chinensis and Psathyrostachys chinensis by utilizing an immature embryo rescue technology. Background Art

[0002] Leymus chinensis ( Leymus chinensis Leymus chinensis is highly adaptable and resistant to cold, drought, alkali, barrenness, and wind and sand. Its abundant leaves, high nutritional value, and palatability make it a popular food for all types of poultry year-round. Its rhizomes possess strong penetrating and invasive abilities, providing wind and sand fixation, making it a key grass for forage and ecological conservation. Leymus chinensis has a wide distribution and abundant germplasm resources. While certain characteristics of current Leymus chinensis germplasm resources vary, the limitations of molecular breeding and conventional intra- and interspecific breeding methods make it difficult to achieve breakthroughs in developing new, high-yield, high-quality, and stress-resistant varieties.

[0003] Distant hybridization is a hybridization process between species, genera, or even more distantly related species. The offspring obtained through distant hybridization have greater genetic variation, providing more resources for selecting materials with high grass yield, high seed yield, better nutritional quality, and improved stress resistance, thereby creating new variants or species.

[0004] Distant hybridization increases the risk of embryo death during development, leading to a low hybrid fruit set rate. Leymus chinensis is a cross-pollinated plant with a low fruit set rate. Coupled with reproductive isolation, producing hybrid offspring through distant hybridization is even more challenging. A report on hybridization between Leymus chinensis and Leymus gracilis (Du Jiancai et al., 1998, "Study on Improving Fruit Set in Leymus chinensis Using Distant Hybridization") has been published. The authors detasseled and pollinated 360 florets, resulting in 76 seeds. However, only two of six seeds sown emerged, ultimately resulting in a single plant. Distant hybridization between Leymus chinensis and Leymus gracilis is an interspecific hybridization of the same genus and polyploidy. However, species of Leymus chinensis and other genera are likely to have different chromosome ploidy. Even if hybrids are produced, they are likely to die prematurely or become sterile, making hybridization even more challenging.

[0005] Embryo rescue technology involves removing immature embryos from undeveloped seeds using tissue culture techniques, sterilizing them, and inoculating them onto culture medium to cultivate them into seedlings. By providing the embryos with an appropriate growth environment, including hormone levels, temperature, and light, the survival rate of the embryos and the success rate of hybrid offspring are improved, resulting in a higher number of hybrid offspring. Currently, embryo rescue technology has been successfully applied in a number of plant species, including early-ripening peaches (Patent Grant Announcement No. CN 105284620 B), jasmine (Patent Application Publication No. CN112470920 A), rice (Patent Application Publication No. CN 111264386 A), sesame (Patent Application Publication No. CN105104185 B), and seedless grapes (Patent Grant Announcement No. CN 104782474 B). However, there have been no reports of embryo rescue technology in Leymus chinensis breeding.

[0006] Pseudomonas aeruginosa is a perennial, densely packed, low-growing grass with multiple beneficial traits: early greening, abundant tillers, tolerance to grazing, drought, and saline-alkali stress. It is a suitable forage grass for both grazing and mowing in arid and semi-arid regions. Pseudomonas aeruginosa has a rich germplasm resource and high genetic variation, providing a rich gene pool for improving seed yield, forage yield, and disease resistance in Leymus chinensis. By hybridizing Leymus chinensis with Pseudomonas aeruginosa, superior genes from Pseudomonas aeruginosa can be transferred to Leymus chinensis, improving seed yield, forage yield, and resistance to rust and aphids. By identifying and evaluating the hybrid offspring, Leymus chinensis germplasm with even superior characteristics can be selected, leading to the development of new Leymus chinensis varieties.

[0007] However, sheepgrass and Psathyrostachys belong to species of different genera, and hybrid breeding is difficult. How to use embryo rescue technology to solve the problem of difficulty and long time in obtaining hybrid F1 plants when conducting distant hybridization between sheepgrass and Psathyrostachys, which is distantly related, is a topic that urgently needs to be studied. Summary of the Invention

[0008] The purpose of the present invention is to overcome the shortcomings of the existing technology and provide a method for obtaining offspring of distant hybridization between Leymus chinensis and Psathyrostachys chinensis using immature embryo rescue technology, so as to solve the problem that it is difficult and time-consuming to obtain hybrid F1 plants when performing distant hybridization between Leymus chinensis and Psathyrostachys chinensis, which is more distantly related.

[0009] The object of the present invention is achieved through the following technical solution: a method for obtaining offspring of distant hybridization between Leymus chinensis and Psathyrostachys chinensis using immature embryo rescue technology, comprising the following steps:

[0010] 1) Hybridization:

[0011] Leymus chinensis was used as the female parent, and Pseudocymphaea chinensis was used as the male parent. 24 hours before the female parent shed pollen, the spikelets at the top and base of the spikelet were removed, and the middle florets of the remaining spikelets were removed, leaving only the two outermost florets. The flowers were then detasseled and bagged. Pollen from the male parent was collected and applied to the stigma of the female parent's pistil with tweezers for pollination, and immediately bagged.

[0012] 2) Disinfection:

[0013] After pollination, the hybrid ears were taken, the non-aborted ovaries were peeled out, and they were soaked in 75% alcohol for 1 min, rinsed three times with sterile water, soaked in 10% v / v sodium hypochlorite for 10 min, and then rinsed with sterile water five times.

[0014] 3) Use one-step seedling method or callus induction and propagation, differentiation and seedling method to produce seedlings;

[0015] The one-step seedling method comprises the following steps: peeling off hybrid immature embryos, placing them in a germination medium, culturing the germination medium containing the hybrid immature embryos in an incubator at a temperature of 25° C., 16 hours of light and 8 hours of darkness for 28 days, and directly germinating and developing into seedlings; the germination medium comprises 4.4 g / L MS, 30 g / L sucrose, 8 g / L agar, and 0.5 mg / L gibberellin, and the pH value of the germination medium is 5.8;

[0016] The method for inducing callus propagation and differentiating into seedlings comprises the following steps: peeling off hybrid immature embryos, inoculating them into callus induction medium, and culturing them in a dark incubator at a temperature of 25° C. for 28 days; using the callus induction medium, subculturing and proliferating them under the same conditions as the callus induction culture for 14 days, transferring them to a differentiation medium, culturing them in a incubator at 25° C., with a light intensity of 16 hours and a darkness of 8 hours for 28 days; and transferring them to a rooting medium and culturing them for 21 days; the callus induction medium comprises 4.4 g / L MS, 30 g / L sucrose, 8 g / L agar, 0.5 mg / L gibberellin, 2 mg / L 2,4-D and 1 mg / L yeast extract YE, and the pH value of the callus induction medium is 5.8; the differentiation medium comprises 4.4 g / L MS, 30 g / L sucrose, 8 g / L agar, 1.0 mg / L-2.0 mg / L gibberellin and 0.5 mg / L-2 mg / L 6-BA, the pH value of the differentiation medium is 5.8; the rooting medium includes 2.2 g / L MS, 30 g / L sucrose, 8 g / L agar and 1.0 mg / L NAA, and the pH value of the rooting medium is 5.8;

[0017] 4) Hardening and transplanting seedlings: When the tissue culture seedlings grow to 10 cm-15 cm, add ultrapure water to the culture bottle. After hardening the seedlings indoors for 7 days, rinse the culture medium around the roots of the plants and transplant them into sterilized nutrient soil for cultivation.

[0018] In step 1), pollination is repeated 24 hours after the first pollination.

[0019] In step 2), the hybrid ears are hybrid ears 14-18 days after pollination.

[0020] In the step 2), the non-aborted ovary is a green, plump, disease- and insect-free non-aborted ovary.

[0021] The beneficial effects of the present invention are as follows: the present invention uses distantly related wheatgrass and chinensis for distant hybridization, adopts the young embryo rescue technology, and optimizes the hybridization method to successfully obtain hybrid offspring plants in a relatively short time. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is the seedling formation situation of the hybrid combination 24×P24 using the embryo rescue one-step seedling formation method;

[0023] Figure 2 This is the callus induction situation of the hybrid combination 0×P24 hybrid immature embryo;

[0024] Figure 3 This is the differentiation status of callus tissues of different hybrid combinations grown on differentiation medium for 28 days;

[0025] Figure 4 This is the rooting situation of differentiated tissues of different hybrid combinations grown on rooting medium for 21 days;

[0026] Figure 5 It shows the growth of hybrid embryo plants of different hybrid combinations after transplantation. DETAILED DESCRIPTION

[0027] The present invention is described in detail below with reference to the accompanying drawings.

[0028] The method for obtaining distant hybridization offspring of Leymus chinensis and Psathyrostachys chinensis by using the immature embryo rescue technique comprises the following steps:

[0029] 1. Hybrid parents: The germplasm resources in the National Perennial Forage Germplasm Resource Nursery of Hohhot, Institute of Grassland, Chinese Academy of Agricultural Sciences were selected for hybridization. The hybrid combinations were 49×Q24, 24×P24, and 0×P24 (the former is the material number of the female parent, Leymus chinensis, and the latter is the material number of the male parent, Pseudomonas sylvestris).

[0030] Among them, the plant height of Leymus chinensis No. 0 is 90-115 cm, the leaf layer height is 60-75 cm, the seed yield is 250.43 kg / hectare on average, and the hay yield is 8174.52 kg / hectare on average; the plant height of Leymus chinensis No. 24 is 85-95 cm, the seed yield is 280.25 kg / hectare on average, and the hay yield is 7014.15 kg / hectare on average; the plant height of Leymus chinensis No. 49 is 110-125 cm, the seed yield is 265.18 kg / hectare on average, and the hay yield is 8764.45 kg / hectare on average.

[0031] The plant height of new wheat straw Q24 is 100-115 cm, the average seed yield is 310.24 kg / hectare, and the average hay yield is 3327.44 kg / hectare; the plant height of new wheat straw P24 is 110-125 cm, the average seed yield is 355.71 kg / hectare, and the average hay yield is 4013.29 kg / hectare.

[0032] The selected parents, Leymus chinensis 0, 24, 49, and Psammophila paniculata Q24 and P24, differ in plant height, seed yield, and hay yield. It is hoped that more outstanding offspring will be obtained through distant hybridization.

[0033] 2. Hybridization: 24 hours before pollen shedding, remove the spikelets at the top and base of the spikelets. Remove the central florets from the remaining spikelets, leaving only the two outermost florets. Then, detassel and bag the flowers. Collect pollen from the male parents of the hybrid combination, New Wheatgrass Q24 and P24. Use tweezers to apply pollen to the stigma of the female parent. Immediately bag the flowers and attach a label indicating the experimenter, time, parent parent, and serial number.

[0034] Because the pollen of Pseudomonas aeruginosa is fine and the styles of Leymus chinensis are relatively small, the present invention uses the tip of tweezers to apply pollen to the stigma of the female plant's pistil, largely avoiding contact or damage to the style. Pollination was repeated 24 hours later to increase embryo formation rates. The hybrid combinations 49×Q24, 24×P24, and 0×P24 pollinated 232, 396, and 574 florets, respectively.

[0035] 3. Disinfection: Take hybrid panicles 14-18 days after pollination, remove the lemma, peel out the non-aborted, green, and plump seeds, soak them in 75% alcohol for 1 minute, rinse them three times with sterile water, soak them in 10% (v / v) sodium hypochlorite for 10 minutes, and then rinse them 5 times with sterile water.

[0036] The present invention selects hybrid ears 14-18 days after pollination for embryo extraction, which can improve the germination rate of immature embryos. Because sodium hypochlorite is highly toxic, the present invention uses 10% (v / v) sodium hypochlorite soaking for 10 minutes to disinfect the seeds, reducing the risk of poisoning during the experiment.

[0037] 4. One-step seedling method: Under a dissecting microscope, remove hybrid embryos and place them on germination medium 1 and germination medium 2, respectively; germination medium 1: 4.4 g / L MS (MS basic medium) + 30 g / L sucrose + 8 g / L agar + 0.5 mg / L gibberellin, pH 5.8; germination medium 2: 4.4 g / L MS (MS basic medium) + 30 g / L sucrose + 8 g / L agar + 0.5 mg / L gibberellin + 1 mg / L yeast extract YE, pH 5.8; the germination medium containing hybrid embryos was placed in an incubator at 25°C, 16 h light and 8 h dark, and directly germinated and developed into seedlings. The germination rate was calculated after 28 days.

[0038] The hybrid embryos began to germinate 5 days after being inoculated into the germination medium and germinated gradually until the 15th day. The germination rates of the hybrid combinations 49×Q24, 24×P24, and 0×P24 on germination medium 1 were 92.31%, 89.47%, and 92.31%, respectively, with an average germination rate of 91.36%; the germination rates of the hybrid combinations 49×Q24, 24×P24, and 0×P24 on germination medium 1 were 88.24%, 71.43%, and 77.78%, respectively, with an average germination rate of 79.15%. The growth of the hybrid combination 24×P24 embryos on the 0th, 5th, and 15th days after being inoculated into germination medium 1 are shown in Figure 2. Figure 1 The embryo germination medium 1 obtained a higher germination rate.

[0039] Gibberellic acid (GAs) promotes the germination of seeds of Leymus chinensis. In the present invention, 0.5 mg / L GAs is added to the germination medium to promote embryo germination. There are no research reports on the addition of GA3 in related tissue culture experiments of Leymus chinensis.

[0040] Because there are no relevant reports on distant hybridization breeding of Leymus chinensis, the present invention also carried out hybridization experiments without embryo rescue. That is, after hybridizing 49xQ24, 24xP24, and 0xP24, their seeds were allowed to mature naturally on the plant, the seeds were harvested, and then a seed germination experiment was carried out. After the filter paper was soaked with distilled water, it was spread on a culture dish. The seeds were clamped to the filter paper with tweezers and germinated in an incubator with 25°C light for 16 hours and 15°C darkness for 8 hours. The germination rate was calculated and the results showed that the germination rates of 49xQ24, 24xP24, and 0xP24 were only 14.29%, 25.38%, and 5.88% respectively. Therefore, the embryo rescue technology can greatly improve the germination rate of distant hybridization offspring.

[0041] 5. Callus induction, propagation, and seedling differentiation method: Under a dissecting microscope, young embryos were removed and inoculated into callus induction medium 1 and callus induction medium 2, respectively; callus induction medium 1: 4.4 g / L MS (MS basic medium) + 30 g / L sucrose + 8 g / L agar + 1 mg / L yeast extract YE + 0.5 mg / L gibberellin + 2 mg / L 2,4-D (2,4-dichlorophenoxyacetic acid), pH 5.8; callus induction medium 2: 4.4 g / L MS (MS basic medium) + 30 g / L sucrose + 8 g / L agar + 2 mg / L yeast extract YE + 0.5 mg / L gibberellin + 2 mg / L 2,4-D (2,4-dichlorophenoxyacetic acid), pH 5.8; cultured in a dark incubator at 25°C, the callus rate was counted after 28 days; after 14 days of subculture and proliferation under the same conditions as the callus induction culture, the callus was transferred to differentiation medium: 4.4 g / L MS (MS basic medium) + 30 g / L sucrose + 8 g / L agar + (1.0 mg / L-2.0 mg / L) gibberellin + (0.5 mg / L-2 mg / L) 6-BA (6-benzylaminopurine), pH 5.8, was cultured in an incubator at 25°C, 16 h of light and 8 h of darkness for 28 days, and the differentiation rate was calculated; the cells were transferred to rooting medium: 2.2 g / L MS (MS basic medium) + 30 g / L sucrose + 8 g / L agar + 1.0 mg / L NAA (naphthaleneacetic acid), and the rooting rate was calculated after 21 days of culture.

[0042] Hybrid embryos inoculated into callus induction medium produced milky white, dense, granular calli. After 28 days of culture, the calli were divided into several small pieces for subculture. Callus induction medium 1, supplemented with 0.5 mg / L gibberellin and 2 mg / L 2,4-D, and 1 mg / L yeast extract, produced callus induction rates of 90.00%, 92.86%, and 100.00%, respectively, for an average callus induction rate of 94.29%. Callus induction medium 2, supplemented with 0.5 mg / L gibberellin and 2 mg / L 2,4-D, and further supplemented with 2 mg / L yeast extract, yielded callus induction rates of 85.71%, 86.96%, and 72.73%, respectively, from immature embryos of the hybrid combinations 49×Q24, 24×P24, and 0×P24, respectively, reaching an average callus induction rate of 81.80%. Callus induction medium 1 yielded a higher callus induction rate from immature embryos.

[0043] The callus growth of hybrid combination 0×P24 immature embryos on the callus induction medium 1 on the 21st, 42nd and 60th days after inoculation is shown in Figure 2. Figure 2 , the callus tissue is in good growth condition.

[0044] After 14 days of subculture, the young embryos of the hybrid combinations 49×Q24, 24×P24, and 0×P24 were transferred to the culture medium of 6 differentiation systems. The hormone levels in the different differentiation systems are shown in Table 1. The calli of the different hybrid combinations were grown in the differentiation medium under light conditions for 28 days and differentiated into leaves. Figure 3 Table 2 shows the differentiation rates of the three hybrid combinations under different differentiation systems. As shown in Table 2, all three hybrid combinations were able to differentiate in all six differentiation systems, but the differentiation rates varied. The differentiation rates of the 0×P24 and 49×Q24 hybrid combinations in the B1, B2, and B3 differentiation systems were higher than those in the B4, B5, and B6 differentiation systems, indicating that the optimal concentration of gibberellins for promoting callus differentiation is 1 mg / L. The 0×P24 hybrid combination had the highest differentiation rate in the B2 system, reaching 77.50%, while the 49×Q24 hybrid combination had the same and highest differentiation rate in both the B1 and B2 systems, reaching 75.00%. Therefore, the optimal hormone ratio for these two hybrid combinations is 1 mg / L gibberellin + 1 mg / L 6-BA. The differentiation rates of the 24×P24 hybrid combination in the B1 and B4 systems were significantly higher than those in the other four systems, indicating that the optimal concentration of 6-BA for promoting callus differentiation is 0.5 mg / L. The differentiation rate of the B4 system was higher than that of the B1 system, so the optimal hormone ratio of the 24×P24 hybrid combination was 2 mg / L gibberellin + 0.5 mg / L 6-BA.

[0045] The differentiation rate of hybrid embryos of the 49×Q24 hybrid combination on the 1mg / L GA3 +0.5mg / L 6-BA differentiation medium was 75%, the differentiation rate of hybrid embryos of the 0×P24 hybrid combination on the 1mg / L GA3 +1mg / L 6-BA differentiation medium was 77.50%, and the differentiation rate of hybrid embryos of the 24×P24 hybrid combination on the 2mg / L GA3 +0.5mg / L BA differentiation medium was 84.44%, all of which were high.

[0046]

[0047] When the adventitious buds grew to 2 cm, they were transferred to the rooting medium. Differentiated tissues of different hybrid combinations grew in the rooting medium for 21 days and produced more roots. Figure 4 The rooting rates of the hybrid combinations 49×Q24, 24×P24, and 0×P24 were 90%, 71%, and 80%, respectively.

[0048] 6. Hardening and transplanting: When the tissue culture seedlings of the hybrid combinations 49×Q24, 24×P24, and 0×P24 grew to 10 cm-15 cm, ultrapure water was added to the culture bottles. After 7 days of hardening, the culture medium around the roots of the plants was rinsed clean and the plants were transplanted into sterilized nutrient soil for cultivation. The transplant survival rate was 100%. A total of 23 49×Q24 hybrid offspring, 25 24×P24 hybrid offspring, and 15 0×P24 hybrid offspring were obtained. Figure 5 The nutrient soil used was purchased from the Clivia advanced formula soil produced by Shandong Xindema Biotechnology Co., Ltd. The main components of the nutrient soil are high-quality peat, coconut bran and perlite.

[0049] The germination rates of the young embryos of the hybrid combinations 49×Q24, 24×P24, and 0×P24 on the screened germination medium were all above 89%, the callus induction rates on the screened callus induction medium were all above 90%, and the differentiation rates on the screened differentiation medium were all above 75%. A large number of hybrid F1 plants were obtained, and hybrid F1 plants could be obtained in less than one month through the one-step seedling method, which greatly saved breeding time.

[0050] Finally, it should be noted that the above content is only used to illustrate the technical solution of the present invention, rather than to limit the scope of protection of the present invention. Simple modifications or equivalent substitutions of the technical solution of the present invention by ordinary technicians in this field do not deviate from the essence and scope of the technical solution of the present invention.

Claims

1. A method for obtaining distant hybridization offspring of Leymus chinensis and Psathyrostachys chinensis using immature embryo rescue technology, characterized in that The following steps are involved: 1) Hybridization: Leymus chinensis was used as the female parent, and Pseudocymphaea chinensis was used as the male parent. 24 hours before the female parent shed pollen, the spikelets at the top and base of the spikelet were removed, and the middle florets of the remaining spikelets were removed, leaving only the two outermost florets. The flowers were then detasseled and bagged. Pollen from the male parent was collected and applied to the stigma of the female parent's pistil with tweezers for pollination, and immediately bagged. 2) Disinfection: After pollination, the hybrid ears were taken, the non-aborted ovaries were peeled out, and they were soaked in 75% alcohol for 1 min, rinsed three times with sterile water, soaked in 10% v / v sodium hypochlorite for 10 min, and then rinsed with sterile water five times. 3) Use one-step seedling method or callus induction and propagation, differentiation and seedling method to produce seedlings; The one-step seedling method comprises the following steps: peeling off hybrid immature embryos, placing them in a germination medium, culturing the germination medium containing the hybrid immature embryos in an incubator at a temperature of 25° C., 16 hours of light and 8 hours of darkness for 28 days, and directly germinating and developing into seedlings; the germination medium comprises 4.4 g / L MS, 30 g / L sucrose, 8 g / L agar, and 0.5 mg / L gibberellin, and the pH value of the germination medium is 5.8; The method for inducing callus propagation and differentiating into seedlings comprises the following steps: peeling off hybrid immature embryos, inoculating them into callus induction medium, and culturing them in a dark incubator at a temperature of 25°C for 28 days; using the callus induction medium, subculturing and proliferating them for 14 days under the same conditions as the callus induction culture, transferring them to a differentiation medium, culturing them in a incubator at 25°C, with a light intensity of 16 hours and a darkness of 8 hours for 28 days; transferring them to a rooting medium and culturing them for 21 days; the callus induction medium comprises 4.4 g / L MS, 30 g / L sucrose, 8 g / L agar, 0.5 mg / L gibberellin, 2 mg / L 2,4-D and 1 mg / L yeast extract YE, and the pH value of the callus induction medium is 5.8; the differentiation medium comprises 4.4 g / L MS, 30 g / L sucrose, 8 g / L agar, 1.0 mg / L-2.0 mg / L gibberellin and 0.5 mg / L-2 mg / L The pH value of the differentiation medium is 5.8; the rooting medium is composed of 2.2 g / LMS, 30 g / L sucrose, 8 g / L agar and 1.0 mg / L NAA, and the pH value of the rooting medium is 5.8; 4) Hardening and transplanting seedlings: When the tissue culture seedlings grow to 10 cm-15 cm, add ultrapure water to the culture bottle. After hardening the seedlings indoors for 7 days, rinse the culture medium around the roots of the plants and transplant them into sterilized nutrient soil for cultivation.

2. The method for obtaining distant hybridization offspring of Leymus chinensis and Psathyrostachys chinensis by using the immature embryo rescue technique according to claim 1, characterized in that: In step 1), pollination is repeated 24 hours after the first pollination.

3. The method for obtaining distant hybridization offspring of Leymus chinensis and Psathyrostachys chinensis by using the immature embryo rescue technique according to claim 1, characterized in that: In step 2), the hybrid ears are hybrid ears 14-18 days after pollination.

4. The method for obtaining distant hybridization offspring of Leymus chinensis and Psathyrostachys chinensis by using the immature embryo rescue technique according to claim 1, characterized in that: In the step 2), the non-aborted ovary is a green, plump, disease- and insect-free non-aborted ovary.

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