Perennial cereal

Abstract

To create a plant of the genus Fagopyrum having improved drought resistant by hybridization of creating a plant of the genus Fagopyrum having improved humidity resistance, and create a perennial plant of the genus Fagopyrum having reduced bitterness by hybridization.SOLUTION: Provided is a plant of the genus Fagopyrum obtained by cross-breeding perennial buckwheat Fagopyrum cymosum with a plant of the genus Fagopyrum having none or a trace amount of rutinosidase activity.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a buckwheat plant obtained by crossing perennial buckwheat Fagopyrum cymosum with a buckwheat plant having no or trace rutinase activity. Further, the present invention relates to a buckwheat plant having moisture tolerance and / or cold tolerance. The present invention relates to a method for producing a perennial buckwheat plant including a step of crossing perennial buckwheat F. cymosum with a buckwheat plant having no or trace rutinase activity.

Background Art

[0002] Perennial grains generally have vigorous root development, very high dry matter production capacity, quick recovery even in the face of environmental stress, and can be cultivated with a significant reduction in fertilizers, pesticides, and herbicides. Currently, the mainstream annual grains require annual sowing and harvesting operations. On the other hand, once perennial grains are sown, only harvesting operations are required for decades to come, enabling ultimate labor-saving cultivation.

[0003] Research on perennial grains has mainly been carried out on wheat and rice, but the cultivation areas of perennial wheat and rice are currently narrower compared to those of annuals, and the yields are also lower compared to annuals (for example, Non-Patent Document 1). In addition, perennial wheat is vulnerable to waterlogging and high temperatures, and perennial rice dies due to frost, so it is not suitable for cultivation in the warm and humid climate, which is a typical climate zone in Japan.

[0004] Perennial cereal candidates that can adapt to a warm and humid climate include perennial buckwheat. Cultivated species of the genus Fagopyrum, which is classified in the Polygonaceae family, include annual common buckwheat (Fagopyrum esculentum), annual tartary buckwheat (F. tataricum), and perennial root buckwheat (F. cymosum). In Japan, common buckwheat and tartary buckwheat are mainly used as food. In China, the roots of F. cymosum are used as traditional Chinese medicine, but the seeds have a strong bitterness and are not used as food. Furthermore, perennial root buckwheat has seed shattering, making it difficult to harvest, and even if it can be harvested, the yield is low.

[0005] Buckwheat may be damaged by waterlogging due to heavy rain immediately after sowing or continuous rain during the growth period, and is particularly susceptible to waterlogging in paddy field rotation cultivation. However, no annual buckwheat varieties with waterlogging tolerance have been found. It is not known whether F. cymosum has waterlogging tolerance in a warm and humid climate.

[0006] Artificial crosses using F. cymosum as the parent have been carried out. For example, F. giganteum Krotov and F. tatari-cymosum Chen QF have been produced (Non-Patent Document 2). However, F. giganteum Krotov is annual and has smaller seeds than tartary buckwheat, so it has not been cultivated. F. tatari-cymosum Chen QF is perennial, but no reports have been made on waterlogging tolerance or bitterness improvement.

Prior Art Documents

Non-Patent Documents

[0007]

Non-Patent Document 1

Non-Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0008] An object of the present invention is to produce a buckwheat plant with improved moisture tolerance by crossing. Another object of the present invention is to produce a buckwheat plant with improved drought tolerance by crossing. Still another object of the present invention is to produce a buckwheat plant that is perennial and has reduced bitterness by crossing.

Means for Solving the Problems

[0009] The present invention provides the following inventions. [1] A buckwheat plant obtained by crossing Fagopyrum cymosum with a buckwheat plant having no or trace rutinase activity. [2] The buckwheat plant according to [1], which is perennial. [3] The buckwheat plant according to [1] or [2], which is moisture-tolerant. [4] The buckwheat plant according to any one of [1] to [3], which is drought-tolerant. [5] The buckwheat plant according to [1], which has moisture tolerance and one or more traits selected from the following: · The yield is 50% or more higher than that of common buckwheat. · It is drought-tolerant. · The seed shattering property is reduced or there is no seed shattering property. · The bitterness is reduced or there is no bitterness. · The rutinase activity is 30 nkat or less per 1 g of seeds excluding the husk. · It is perennial. · It has soil freezing tolerance. · It has disease resistance. · It has insect resistance. · Resistant to pre-harvest sprouting, · Having a high survival rate in vegetative propagation. [6] A buckwheat plant according to [1], which is drought-tolerant and has one or more traits selected from the following: · Having a yield 50% or more higher than that of common buckwheat, · Being moisture-tolerant, · Having reduced seed shattering or no seed shattering, · Having reduced bitterness or no bitterness, · Having rutinase activity of 30 nkat or less per 1 g of seeds excluding the husk, · Being perennial, · Having soil freezing tolerance, · Being disease-resistant, · Being insect-resistant, · Resistant to pre-harvest sprouting, · Having a high survival rate in vegetative propagation. [7] A buckwheat plant according to [1], which is perennial and has one or more traits selected from the following: · Having a yield 50% or more higher than that of common buckwheat, · Being moisture-tolerant, · Being drought-tolerant, · Having reduced seed shattering or no seed shattering, · Having reduced bitterness or no bitterness, · Having rutinase activity of 30 nkat or less per 1 g of seeds excluding the husk, · Having soil freezing tolerance, · Being disease-resistant, · Being insect-resistant, · Resistant to pre-harvest sprouting, · Having a high survival rate in vegetative propagation. [8] A food product containing a part of the plant body of a buckwheat plant according to any one of [1] to [7]. [9] A method for producing a perennial buckwheat plant, The production method includes a step of crossing Fagopyrum cymosum with a buckwheat plant having no or trace rutinase activity. In the obtained progeny plants, select plants that produce shoots from the stock base in the first year of cultivation, or select plants having two or more roots with a diameter of 1 cm or more Thereby, the method for producing a perennial buckwheat plant according to [9], which includes the step of selecting a perennial plant.

Effect of the Invention

[0010] According to the present invention, it is possible to provide a perennial buckwheat plant with improved moisture tolerance. According to the present invention, it is possible to provide a buckwheat plant with improved drought tolerance. According to the present invention, it is possible to provide a buckwheat plant that is perennial and has reduced bitterness.

[0011] With the buckwheat plant obtained by the present invention, cultivation in fields where waterlogging or drought damage occurs becomes possible, cultivation in regions where soil freezing occurs becomes possible, and / or cultivation can be labor-saving due to its perennial nature, and added value can be obtained through high quality.

Brief Description of the Drawings

[0012]

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Modes for Carrying Out the Invention

[0013] The description of the present invention described below may be made based on representative embodiments or specific examples, but the present invention is not limited to such embodiments. In this specification, the numerical range represented by "~" means a range including the numerical values described before and after "~" as the lower limit value and the upper limit value.

[0014] Definition In this specification, "annual plant" refers to a life cycle in which, in temperate to subarctic climates, it germinates after sowing in spring or summer, flowers and bears fruit from summer to autumn, and the roots, stems, and leaves wither within the same year. The reproduction of annual plants is by seeds.

[0015] In this specification, "perennial plant" refers to a life cycle in which the same individual overwinters and grows in the following year. In the case of perennial buckwheat plants, in temperate to subarctic climates, the above-ground part withers in winter, but the underground rhizome remains alive, sprouts from the rhizome in the following spring, and flowers and bears fruit from summer to autumn, and this life cycle is repeated for two or more years. Whether a buckwheat plant is perennial can be confirmed by the presence of sprouting from the rhizome in spring. Since annual plants wither in winter and do not regenerate, perennial plants can be selected by overwintering the plants. The photograph in Figure 1 shows the sprouting of hybrid overwintering plants.

[0016] In this specification, "waterlogging damage" refers to the situation where the plant body withers or dies due to the roots being immersed in water and insufficient oxygen supply. Buckwheat plants are particularly vulnerable to waterlogging damage from the sowing stage to the young plant stage. Waterlogging damage is likely to occur in paddy field converted upland field cultivation. In this specification, "waterlogging tolerance" means tolerance to waterlogging damage, and the degree of enhanced waterlogging tolerance can be detected by submerging treatment. The submerging treatment can be carried out under flowing water conditions or water storage (non-flowing water) conditions. The irrigation treatment under flowing water conditions can be carried out by sowing in a plant pot, and 3 weeks after sowing, putting the pot into a container with a depth such that the upper end of the pot is immersed in water for 21 days, and constantly injecting water into the container with a hose. The irrigation treatment under water storage conditions can be carried out by putting the pot into a container with a depth such that the upper end of the pot is immersed in water for 21 days 3 weeks after sowing, storing water, and injecting water when the water level drops. One week after the end of the irrigation treatment, the surviving individuals can be counted to obtain the survival rate.

[0017] As used herein, "drought tolerance" refers to the tolerance to drought damage. Drought tolerance can be detected by comparing the growth degree such as survival rate and plant height between a plot cultivated without watering after shielding the plant body from rain with a hood or the like so that rain does not fall thereon, and a plot cultivated with appropriate watering. Specifically, it can be evaluated by sowing in a plant pot, performing a 3-day drying treatment (without watering) 4 weeks after sowing, counting the surviving individuals 1 week after the end of the drying treatment, and obtaining the survival rate.

[0018] As used herein, "seed shattering" refers to the characteristic that seeds fall off from the inflorescence at the mature stage. Regarding seed shattering, it can be detected by whether the seeds fall off when the seeds on the plant body at the mature stage are shaken 20 times in 10 seconds, moving 20 cm each time.

[0019] As used herein, "soil freezing tolerance" means the tolerance to soil freezing, particularly the tolerance to soil freezing from the soil surface to a depth of 2 to 3 centimeters.

[0020] As used herein, "bitterness" refers to the bitter taste of buckwheat grains. The grains of Dattan soba have a high rutin content. When water is added to buckwheat flour to produce noodles or the like, most of the rutin contained in the grains is decomposed, and the taste becomes strongly bitter. The decomposition of rutin is caused by rutinosidase activity.

[0021] As used herein, "the bitterness is reduced or there is no bitterness" means that the taste of the grains or buckwheat processed foods is weaker than that of the bitter variety of Dattan soba, for example, Hokkaido T8, or there is no bitterness. "The bitterness is reduced or there is no bitterness" is due to a low rutin content, a weak rutinosidase activity, or both. Bitterness can be evaluated by putting the seeds in the mouth. It can also be evaluated by measuring the rutinosidase activity.

[0022] "Rutin" is a type of polyphenol and one of the representative functional substances found in buckwheat. It is said to be contained only in buckwheat among grains. An improvement effect on lipid metabolism has been reported with an intake of 360 mg in a human intervention study. The rutin content rate can be detected by measuring rutin using HPLC or the like.

[0023] In this specification, "rutinase activity" means the enzyme activity that decomposes rutin. Rutinase activity triggers the generation of bitter substances in tartary buckwheat. When rutin is hydrolyzed by the reaction catalyzed by rutinase, quercetin, a bitter substance, is produced. Since the rutin-decomposing activity of conventional tartary buckwheat seeds is very strong, most of the rutin is decomposed when water is added to tartary buckwheat flour. Rutinase activity can be measured by the method of Suzuki et al. (2004). Suzuki, T., Honda, Y., Funatsuki, W. and Nakatsuka, K. (2004), In-gel detection and study of the role of flavonol 3-glucosidase in the bitter taste generation in tartary buckwheat. J. Sci. Food Agric., 84: 1691-1694. https: / / doi.org / 10.1002 / jsfa.1865

[0024] In this specification, "yield" refers to the yield per 10 ares of dry seeds. For common buckwheat, the national average yield in Japan in 2021 was 62 kg / 10 ares (https: / / www.maff.go.jp / j / tokei / kekka_gaiyou / sakumotu / sakkyou_kome / kougei / r3 / soba / index.html). The yield of hybrids can be evaluated by cultivating them in the same field as the control buckwheat plants of the genus and measuring the weight of the dry seeds.

[0025] In this specification, "seedling" refers to a plant 1 to 3 weeks after sowing. In this specification, the "maturity period" means the appropriate harvesting period when the buckwheat seeds are mature. The maturity period can be determined, for example, by the blackening rate.

[0026] Fagopyrum cymosum, a perennial buckwheat, is mainly cultivated in China. Its seeds are strongly bitter and have seed shattering characteristics.

[0027] Fagopyrum tataricum is a cultivated plant species in the genus Fagopyrum and is cultivated mainly in China, as well as in Russia, EU countries, Nepal, etc. In fiscal year 2012, it was cultivated on about 300 ha across Japan, with Hokkaido being the main production area. Since Fagopyrum tataricum is self-fertile, unlike cross-fertile common buckwheat, it can be cultivated even in severely cold regions where the activities of flower-visiting insects such as flies and bees are restricted by low temperatures. Its seeds contain about 100 times more rutin than those of common buckwheat and are strongly bitter.

[0028] (Plants of the genus Fagopyrum) The present invention relates to a buckwheat plant obtained by crossing perennial buckwheat F. cymosum with a buckwheat plant having no or trace rutinase activity. Any strain or variety can be used for the parental perennial buckwheat F. cymosum. For example, strains identified by the unique numbers "stock No.00046554" and "JP41916" in the gene bank can be used. As the buckwheat plant having no or trace rutinase activity, any strain or variety can be used as the parental strain for crossing as long as it has no rutinase activity or has trace rutinase activity. "Trace" regarding rutinase means that the rutinase activity is extremely low. For example, the trace rutinase activity is 30 nkat or less per 1 g of seeds without husks, or 20 nkat or less per 1 g of seeds with husks. The buckwheat plant having no or trace rutinase activity can be selected from, for example, common buckwheat (Fagopyrum esculentum), tartary buckwheat (Fagopyrum tataricum), wild buckwheat related to buckwheat (Fagopyrum homotropicum), Fagopyrum megaspartanium, Fagopyrum pillus, F agopyrum macrocarpum, Fagopyrum callianthum, Fagopyrum urophyllum, Fagopyrum gilesii, Fagopyrum statice, Fagopyrum leptopodum, Fagopyrum gracilipes, Fagopyrum capillatum, Fagopyrum pleioramosum, Fagopyrum lineare, Fagopyrum rubifolium. For a species known to have high rutinase activity, such as tartary buckwheat, a variety or strain having no rutinase activity or trace rutinase activity can be selected. In a specific embodiment, the buckwheat plant having no or trace rutinase activity may be a trace rutinase variety of tartary buckwheat F. tataricum.The "low rutinase variety" refers to a variety of buckwheat plants with extremely low rutinase activity. For example, it is a variety with a rutinase activity of 30 nkat or less per 1 g of seeds without husks, or 20 nkat or less per 1 g of seeds with husks. An example of a "low rutinase variety" of Fagopyrum tataricum is, but not limited to, "Manten Kirari". "Manten Kirari" is a variety developed by crossing the standard variety "Hokkai T8", which has excellent yield and maturity, with the line "f3g162", which has extremely weak bitterness and rutin-decomposing activity. "Manten Kirari" is available under the variety registration number "23414".

[0029] The buckwheat plant obtained by the above cross may be a hybrid F1, or a plant of F2 or later generations obtained by further crossing, or a plant of the second generation (BC2) or later generations obtained by backcrossing. In a specific embodiment, more desirable traits can be introduced into the buckwheat plant obtained by crossing by using gene recombination technology, or genome editing technology using site-directed nuclease 1 (SDN-1) or CRISPR-Cas9.

[0030] Regarding the present invention, unless otherwise specified, the term "plant" is used to mean a whole plant or a part thereof. When referring to "a part thereof", unless otherwise specified, it includes seeds (including germinated seeds and immature seeds), organs or parts thereof (including leaves, roots, stems, flowers, stamens, pistils, and pieces thereof), plant cultured cells, callus, and protoplasts. Plants include genetically engineered plants and transgenic plants. Plants include harvested products and propagation materials. Propagation materials, unless otherwise specified, refer to all or part of a plant used for propagation (sometimes called seedlings), such as seeds, seedlings, cells, callus, and sprouts. The harvested products referred to in the present invention are used in the ordinary sense, unless otherwise specified, and are those not used for propagation from all or part of a plant, such as buckwheat seeds as food raw materials, harvested buckwheat, buckwheat husks, and bran. Regarding the present invention, unless otherwise specified, the term "processed product" refers to a processed product directly produced from a harvested product, specifically, buckwheat grains, buckwheat flour, etc. Buckwheat grains or buckwheat flour can be used as raw materials for food.

[0031] The present invention relates to a part of a plant body of a buckwheat plant obtained by the above-mentioned crossing, for example, seeds. Further, the present invention relates to buckwheat flour milled from the seeds of a buckwheat plant obtained by the above-mentioned crossing. The present invention relates to a food containing a part of a plant body of a buckwheat plant obtained by the above-mentioned crossing. The present invention relates to a food using buckwheat grains or buckwheat flour obtained from a buckwheat plant obtained by the above-mentioned crossing as a raw material. Regarding the present invention, foods include noodles, confectioneries (such as cookies, biscuits, crackers, boros, snacks, sponge cakes, manju, dumplings, senbei, arare, okaki, etc.), mochi, breads (such as sandwich bread, sweet bread, bagels, steamed bread, and butter rolls, etc.), pizza, liquor, ice cream, candies, chocolates, mix powders (such as tempura batter mix, pancake mix, hot cake mix, okonomiyaki mix, and takoyaki mix, etc.), beverages (such as buckwheat tea beverages, soups, green juices, smoothies), etc., and may also include boiled buckwheat grains, gruel of buckwheat grains (such as kasha, etc.), and whole buckwheat grains for mixed grain rice, etc.

[0032] In one embodiment, the buckwheat plant obtained by the crossing is perennial. Being perennial is preferable in terms of labor-saving cultivation because it can be harvested for multiple years once sown.

[0033] In one embodiment, the buckwheat plant obtained by the crossing is moisture-tolerant. Since buckwheat plants are particularly vulnerable to waterlogging during the seedling stage after sowing, moisture tolerance is a particularly preferable trait in buckwheat cultivation. With moisture tolerance, the plants will not wither even under conditions of rainfall or waterlogging, and even if they do not wither, reducing damage will result in increased yields. The survival rate of the buckwheat plant obtained by the crossing after irrigation treatment with running water is 1.2 times or more, 1.3 times or more, 1.4 times or more, 1.5 times or more, 1.6 times or more, 1.7 times or more, 1.8 times or more, 1.9 times or more, 2.0 times or more, 3.0 times or more, 4.0 times or more, 5.0 times or more, 6.0 times or more, 7.0 times or more, 8.0 times or more, 9.0 times or more, or 10 times or more higher than that of other buckwheat plants treated under the same conditions.

[0034] In one embodiment, the buckwheat plant obtained by the crossing is drought-tolerant. A trait that is strong against drought damage is a preferable trait in that it is strong against meteorological disasters such as drought and can expand the suitable cultivation areas. With drought tolerance, the plants will not wither even when there is no rain, and even if they do not wither, reducing damage will result in increased yields. The survival rate of the buckwheat plant obtained by the crossing after drying treatment is 1.8 times or more, 1.9 times or more, 2.0 times or more, 3.0 times or more, 4.0 times or more, 5.0 times or more, 6.0 times or more, 7.0 times or more, 8.0 times or more, 9.0 times or more, or 10 times or more higher than that of other buckwheat plants treated under the same conditions. Moisture tolerance and drought tolerance are traits that lead to stable and high yields.

[0035] In one embodiment, the yield of the buckwheat plant obtained by the crossing is 50% or more higher than that of common buckwheat. If the yield is high, a large number of seeds can be obtained.

[0036] In one embodiment, the buckwheat plant obtained by the crossing has reduced or no seed shattering. Seed shattering is one of the causes of low yields. Reduced or no seed shattering is preferable for cultivated buckwheat varieties.

[0037] In one embodiment, the buckwheat plant obtained by the crossing has reduced or no bitterness. Reduced or no bitterness is important for eating. In one embodiment, the buckwheat plant obtained by the crossing has a rutinase activity of 30 nkat or less per 1 g of seeds without husks, or 20 nkat or less per 1 g of seeds with husks.

[0038] In one embodiment, the buckwheat plant obtained by the crossing has soil freezing tolerance. With soil freezing tolerance, perennial cultivation can be carried out in a warm and humid climate.

[0039] In one embodiment, the buckwheat plant obtained by the crossing has excellent disease resistance. This disease resistance can be effective against representative diseases that occur particularly in buckwheat plants, such as powdery mildew, mosaic disease, and downy mildew. Powdery mildew forms white powdery spores on the leaves and stems of buckwheat plants, inhibiting growth by reducing photosynthetic efficiency. Mosaic disease is caused by a virus, resulting in irregular spotted patterns on the leaves, causing photosynthetic dysfunction and growth stagnation. Downy mildew is mainly caused by fungi, forming grayish-white or yellow lesions on the leaves and stems, and in advanced cases, plant tissue may necrotize and die. These diseases can prevent the growth of buckwheat and ultimately lead to a significant reduction in the harvest. The buckwheat plant obtained by the crossing has higher disease resistance compared to other buckwheat plants, such as perennial buckwheat and common buckwheat. The buckwheat plant obtained by the crossing has improved disease resistance.

[0040] In one embodiment, the buckwheat plant obtained by the crossing has excellent insect resistance. This insect resistance can be effective against pests typical of buckwheat plants, such as the corn earworm, aphids, as well as the common cutworm, the oriental armyworm, and the black hornet. The larvae of the corn earworm, the common cutworm, the oriental armyworm, the black hornet, etc. damage the leaves and inhibit the growth of buckwheat. Aphids not only impede growth by sucking the sap of leaves and stems, but also transmit the mosaic virus, and their excrement causes powdery mildew. These pests can significantly impede the growth of buckwheat and may cause a substantial decrease in the yield. The buckwheat plant obtained by the crossing has higher insect resistance compared to other buckwheat plants, such as perennial buckwheat, common buckwheat, and Tartary buckwheat. The buckwheat plant obtained by the crossing has improved insect resistance.

[0041] In one embodiment, the buckwheat plant obtained by the crossing has excellent pre-harvest sprouting resistance. Pre-harvest sprouting refers to the phenomenon in which mature grains germinate due to rainfall before harvest, which can cause a decline in the quality of the grains. The buckwheat plant of the present invention has a higher ability to suppress pre-harvest sprouting compared to conventional varieties and contributes to maintaining the quality of the harvested product. The buckwheat plant obtained by the crossing has stronger pre-harvest sprouting resistance compared to other buckwheat plants, such as common buckwheat and Tartary buckwheat.

[0042] In one embodiment, the buckwheat plant obtained by the crossing has the characteristic of showing a high survival rate in vegetative propagation. Vegetative propagation is a method of multiplying plants using vegetative organs such as roots, stems, and leaves, such as cuttings and grafting. The buckwheat plant obtained by the crossing of the present invention has a high success rate of propagation by these methods and can efficiently propagate individuals with the same traits as the parent. Due to this characteristic, propagation becomes easy while maintaining the stability of the traits.

[0043] In one embodiment, the buckwheat plant obtained by the crossing has moisture tolerance and can have one or more traits selected from the following, preferably two or more, three or more, four or more, five or more, six or more, seven or more, eight or more, nine or more, ten or more, or all: · The yield is 50% or more higher than that of common buckwheat. · It is drought tolerant. · The seed shattering property is reduced or there is no seed shattering property. · The bitterness is reduced or there is no bitterness. · The rutinase activity is 30 nkat or less per 1 g of seeds without husks. · It is perennial. · It has soil freezing tolerance. · It has disease resistance. · It has insect resistance. · It has resistance to pre-harvest sprouting. · It has a high survival rate in vegetative propagation.

[0044] In one embodiment, the buckwheat plant obtained by the crossing is drought tolerant and can have one or more traits selected from the following, preferably two or more, three or more, four or more, five or more, six or more, seven or more, eight or more, nine or more, ten or more, or all: · The yield is 50% or more higher than that of common buckwheat. · It is moisture tolerant. · The seed shattering property is reduced or there is no seed shattering property. · The bitterness is reduced or there is no bitterness. · The rutinase activity is 30 nkat or less per 1 g of seeds without husks. · It is perennial. · It has soil freezing tolerance. · It has disease resistance. · It has insect resistance. · It has resistance to pre-harvest sprouting. · It has a high survival rate in vegetative propagation.

[0045] In one embodiment, the buckwheat plant obtained by the crossing is perennial and can have one or more traits selected from the following, preferably two or more, three or more, four or more, five or more, six or more, seven or more, eight or more, nine or more, ten or more, or all: · The yield is 50% or more higher than that of common buckwheat. · It is moisture-tolerant. · It is drought-tolerant. · The seed shattering property is reduced or there is no seed shattering property. · The bitterness is reduced or there is no bitterness. · The rutinase activity is 30 nkat or less per 1 g of seeds excluding the husk. · It has soil freezing tolerance. · It has disease resistance. · It has insect resistance. · It has resistance to pre-harvest sprouting. · It has a high survival rate in vegetative propagation.

[0046] In a specific embodiment, the buckwheat plant obtained by the crossing is perennial, moisture-tolerant, and cold-tolerant, has soil freezing tolerance, and the seed shattering property is reduced or there is no seed shattering property. In a specific embodiment, the buckwheat plant obtained by the crossing is perennial and the bitterness is reduced or there is no bitterness.

[0047] (Production method) The present invention relates to a method for producing a perennial buckwheat plant, which includes the step of crossing Fagopyrum cymosum with a buckwheat plant having no or trace rutinase activity. Both Fagopyrum cymosum and the buckwheat plant having no or trace rutinase activity can be used as the seed parent and the pollen parent. The buckwheat plant having no or trace rutinase activity can be selected from, for example, common buckwheat (Fagopyrum esculentum), tartary buckwheat (Fagopyrum tataricum), closely related wild buckwheat species (Fagopyrum homotropicum), Fagopyrum megaspartanium, Fagopyrum pillus, Fagopyrum macrocarpum, Fagopyrum callianthum, Fagopyrum urophyllum, Fagopyrum gilesii, Fagopyrum statice, Fagopyrum leptopodum, Fagopyrum gracilipes, Fagopyrum capillatum, Fagopyrum pleioramosum, Fagopyrum lineare, Fagopyrum rubifolium. For a species known to have high rutinase activity, such as tartary buckwheat, a variety or strain having no rutinase activity or trace rutinase activity can be selected. In a specific embodiment, the buckwheat plant having no or trace rutinase activity may be a trace rutinase variety of Fagopyrum tataricum. When the buckwheat plant having no or trace rutinase activity is diploid, it can be tetraploidized by colchicine treatment or the like and crossed with the tetraploid Fagopyrum cymosum. When using a trace rutinase variety of F. tataricum as the parent species, it can be tetraploidized by colchicine treatment (for example, immersing seedlings in a 0.05% (w / v) aqueous colchicine solution for 72 hours) and used for crossing.Mating can be performed using the hot water emasculation method described in Mukasa. Y et al (Euphytica 156, (2007) 319-326. Emasculation of Tartary buckwheat (Fagopyrum tataricum Gaertn.) using hot water.), but is not limited thereto, and can be carried out by mating methods commonly used by those skilled in the art. In this specification, the production method is used in the same meaning as the manufacturing method.

[0048] The method for producing a perennial buckwheat plant of the present invention can include a step of selecting a perennial plant by selecting a plant that shoots from the stock at the first year of cultivation or a plant having two or more roots with a diameter of 1 cm or more in the obtained progeny plants. The obtained progeny plants may be hybrid F1, may be plants of F2 or later generations obtained by further mating, or may be plants of the second generation (BC2) or later generations obtained by backcrossing. By selecting a plant that shoots from the stock at the first year of cultivation or a plant having two or more roots with a diameter of 1 cm or more, a perennial can be selected in the year of sowing. The stock refers to the range from the ground surface to 3 cm above the ground. The presence or absence of shoots can be confirmed 1 month after sowing or later. The number of roots with a diameter of 1 cm or more can be confirmed 6 months after sowing. The step of selecting a perennial plant by selecting a plant that shoots from the stock at the first year of cultivation or a plant having two or more roots with a diameter of 1 cm or more can be carried out to select a perennial plant in the progeny plants obtained by crossing any perennial buckwheat plant with any buckwheat plant, preferably an annual buckwheat plant.

[0049] Example 1: Production of hybrids In this example, the parental species Fagopyrum cymosum and F. tataricum were intercrossed to produce a tetraploid hybrid line. F. cymosum used the strain with the gene bank unique numbers = "stock No. 00046554" and "JP41916". (In the following examples, the parent F. cymosum may be described as perennial buckwheat.) F. tataricum used the cultivar name: "Manten Kirari" (cultivar registration number: "23414"). F. tataricum was tetraploidized by colchicine treatment before use. Both were usable as the seed parent and the pollen parent. Hybrid lines named 22H314, 22N270, 24-1 to 24-8, ZF5-cfND1, and FCND-F4-421 were created, and their traits were evaluated in the subsequent examples.

[0050] Example 2: Moisture tolerance In this example, irrigation treatment was performed on the young plants 1 week and 3 weeks after sowing to verify moisture tolerance. Test method: Irrigation treatment of young plants 1 week after sowing with running water For the hybrid ("ZF5-cfND1") created in Example 1, moisture tolerance was tested. As comparative controls, perennial buckwheat (F. cymosum, gene bank JP number "JP41916"), common buckwheat ("Hitachi Autumn Buckwheat"), and Dattan buckwheat ("Manten Kirari") were used. Seeds of each buckwheat plant were sown in the field on April 6, 2022 (spring sowing) and August 23, 2022 (summer sowing). One week after sowing, submergence treatment with running water was carried out for 5 days, and the survival rate was investigated. Specifically, the seeds of each buckwheat plant were sown in pots, and irrigation treatment was carried out for 5 days 1 week after sowing. The survival rate was measured 1 week after the end of the irrigation treatment. The irrigation treatment with running water was carried out by placing the pots in a container with a depth such that the upper end of the pot was immersed in water and constantly injecting water into the container with a hose. In the irrigation treatment test with running water, six-year-old plants of perennial buckwheat and two-year-old plants of the hybrid ZF5-cfND1 were used as test materials. Since the six-year-old plants of perennial buckwheat and the two-year-old plants of the hybrid were not damaged by the 5-day submergence treatment, the submergence treatment was extended to 14 days, and the survival rate was investigated. Irrigation treatment of young plants 3 weeks after sowing The seeds of the above buckwheat plants were sown in the field, and after 3 weeks of sowing, they were subjected to a flooding treatment with running water for 21 days, and the survival rate was investigated. Specifically, the seeds of each buckwheat plant were sown in pots, and after 3 weeks of sowing, a watering treatment was carried out for 21 days. One week after the end of the watering treatment, the surviving plants were confirmed and the survival rate was measured. The plants that turned black were judged to be dead. The watering treatment was carried out under running water conditions and non-running water (stored water) conditions. The watering treatment with running water was carried out by putting the pot in a depth such that the upper end of the pot was immersed in water and constantly injecting water into the container with a hose. The watering treatment with non-running water was carried out by putting the pot in a container with a depth such that the upper end of the pot was immersed in water, and water was injected when the water level dropped. In the case of the watering treatment with running water, since new water is constantly supplied, the oxygen concentration is high and the growth of miscellaneous bacteria is suppressed, so it is a relatively mild condition as a flooding condition. On the other hand, in the case of the flooding treatment with non-running water, since new water is not supplied, the oxygen concentration in the water is low and there is growth of miscellaneous bacteria, so it is a relatively severe condition as a flooding condition. Results: The results of the watering treatment with running water are shown in Figure 2. The seedlings one week after sowing had a significantly reduced survival rate due to the watering treatment with running water for all the tested species. On the other hand, the survival rates of the six-year-old plants of perennial buckwheat and the two-year-old plants of hybrid ZF5-cfND1 were 100%. The results of the watering treatment with running water for the seedlings three weeks after sowing are shown in Figure 3, and the results of the watering treatment in a non-running water environment (stored water) are shown. For the seedlings three weeks after sowing, the survival rates due to the watering treatment in the running water environment were 26.7% for common buckwheat, 13.3% for Dattan buckwheat, 53.3% for perennial buckwheat, and 80% for the hybrid. The survival rate of the hybrid was the highest. The survival rates due to the watering treatment in the non-running water environment were 0.0% for common buckwheat, 0.0% for Dattan buckwheat, 6.7% for perennial buckwheat, and 33.3% for the hybrid (Figure 4). The survival rate of the hybrid was the highest. Discussion: The hybrid is more resistant to waterlogging (flooding treatment with running water) than its parents, Dattan buckwheat and perennial buckwheat F. cymosum, even as a seedling.

[0051] Example 3: Overwintering Test In this example, an overwintering test was conducted. Test method: Hybrid ("ZF5-cfND1"), common buckwheat ("Hitachi Autumn Buckwheat"), and Dattan buckwheat ("Manten Kirari") were sown in the field on April 6, 2022, overwintered, and the germination and growth status in early spring were evaluated. In addition, wild-growing buckwheat (individuals that germinated in early spring from seeds scattered the previous year) was used to evaluate the resistance to late frost. Results: Common buckwheat and Dattan buckwheat died in winter and could not germinate in early spring. In the hybrid, although the above-ground part withered, the underground part survived, so it was able to germinate in early spring (Figure 5). The wild-growing common buckwheat and Dattan buckwheat in early spring died from the late frost that occurred from April 4 to 5, 2023. Although some of the germinated leaves of the hybrid withered, they quickly regenerated and quickly covered the above-ground part. Discussion: The hybrid can overwinter. Since the test field (Goshi City, Kumamoto Prefecture) is an area where soil freezing occurs, it is considered that the hybrid has resistance to soil freezing. Also, regarding late frost, although the hybrid was damaged, it quickly recovered and quickly covered the ground, so it is considered that the occurrence of weeds during perennial cultivation can be effectively suppressed.

[0052] Characteristics of Perennial Plants Among the hybrids, plants that produced shoots (sprouts) from the root part of the stem (the part close to the roots of the above-ground part, about 3 cm from the ground level, also called the plant base) were observed to overwinter (Figure 6). Annual plants do not produce shoots from the root base, but perennial plants produce shoots from the root base. It became clear that the perennial plants and annual plants can be distinguished even in the first year of cultivation by examining the presence or absence of shoots at the plant base. The following table shows the number of plants that produced shoots from the root base and the number of overwintering plants for hybrids, perennial buckwheat, Dattan buckwheat, and common buckwheat. In common buckwheat and Dattan buckwheat, the buds did not grow upward from the plant base, and the buds that became shoots could be clearly distinguished.

Table 1

[0053] Furthermore, it was observed that the root morphology of hybrid perennial and annual strains differed. The perennial strain had five or more roots with a diameter of 1 cm or more. In the annual strain, there was only one root (main root) with a diameter of 1 cm or more (Figure 7). At least six months after sowing, strains with multiple (two or more) roots with a diameter of 1 cm or more may be judged as perennial strains.

[0054] Example 4: Drought tolerance In this example, drought tolerance was investigated. Test method: Perennial buckwheat (Gene bank JP number "JP41916"), hybrid ("ZF5-cfND1"), common buckwheat ("Hitachi autumn buckwheat"), and Dattan buckwheat ("Manten Kirari") were sown in pots. Three days of drying treatment (no watering) was carried out four weeks after sowing, and the survival rate one week after the end of the drying treatment was investigated. Results: The survival rate of the hybrid was the highest at 86.6%, followed by perennial buckwheat at 46.7%, Dattan buckwheat at 20.0%, and common buckwheat at 13.3% (Figure 8). Discussion: The hybrid may be more resistant to drought damage than its parent varieties, Dattan buckwheat and perennial buckwheat.

[0055] Example 5: Yield In this example, the yield was investigated. Test method: The hybrid ("22N270") and common buckwheat ("Hitachi autumn buckwheat") were sown in separate plots with the same conditions in the same field on August 23, 2022 (summer sowing cultivation), and the above-ground parts were harvested at maturity. After drying at 35°C for one week, the dry weight of the above-ground parts was measured, followed by threshing and cleaning, and the weight of the grains was measured. Note that "Hitachi autumn buckwheat" used as common buckwheat is one of the varieties with the largest cultivation area in summer sowing cultivation in Japan. Results: The total weight and grain weight of the hybrid were higher than those of annual buckwheat (Figure 9). Discussion: The seed weight of common buckwheat was 113 kg / 10 ares, which was more than the national average of 62 kg / 10 ares in Reiwa 3 (Ministry of Agriculture, Forestry and Fisheries statistics data: https: / / www.maff.go.jp / j / tokei / kekka_gaiyou / sakumotu / sakkyou_kome / kougei / r3 / soba / index.html). Therefore, it is considered that the cultivation conditions were favorable for common buckwheat. Moreover, since the seed weight of the hybrid is about three times that of common buckwheat, it is considered that the yield can be improved by making hybrids.

[0056] Example 6: Rutinase activity In this example, rutinase activity was investigated. Test method: Hybrids (8 lines from "24-1" to "24-8"), perennial buckwheat (FC; Gene Bank JP number "JP41916"), bitter Dattan buckwheat (FT; "Hokkaido T8"), and non-bitter Dattan buckwheat (MK; "Manten Kirari") were sown in the field on August 23, 2022 and harvested at maturity. The seed coats were removed, and rutinase activity gel staining in seeds and in vitro rutinase activity were measured by the method of Suzuki et al. (2004) (supra). In gel staining, a crude protein extract equivalent to 55 μg of seeds was applied to each lane. Results: The gel staining photograph is shown in Figure 10. The rutinase activity of the hybrid "24-8" was at a level that could not be detected by this method. Also, the rutinase activity of "24-8" in vitro was "2.4 nkat / g seeds". The rutinase activity of FT was "635 nkat / g seeds". Discussion: Since the rutinase activity of the hybrid "24-8" was lower than that of FT, it is considered possible that it was not bitter.

[0057] Example 7: Seed shattering Perennial buckwheat (Gene bank JP number "JP41916"), hybrid ("FCND-F4-421", "ZF5-cfND1"), common buckwheat ("Hitachi autumn buckwheat"), and Dattan buckwheat ("Manten Kirari") were sown in the field, and shaking treatment (shaking 20 times in 10 seconds (moving about 20 cm each time)) was carried out on the inflorescences at the maturity stage, and the proportion of seeds remaining without falling off from the plants was investigated. Results: For perennial buckwheat ("JP41916"), most of the seeds fell off, but for common buckwheat, Dattan buckwheat, and hybrids, almost no seeds fell off (Figure 11). Discussion: Seed shattering has been improved in hybrids.

[0058] Example 8: Insect resistance and disease resistance In this example, the insect resistance and disease resistance of perennial buckwheat (Gene bank JP number "JP41916"), common buckwheat ("Hitachi autumn buckwheat"), Dattan buckwheat ("Manten Kirari"), and the hybrid of perennial buckwheat and Dattan buckwheat were investigated. In the following experiments, there were 3 replicates for each test plot, and the number of plants in each test plot was 20 or more. <Damage by corn earworm> Various buckwheats were cultivated in the field using conventional methods, and the degree of leaf damage caused by naturally occurring corn earworms (larvae of corn borers) was observed and evaluated by scoring. 0 points: no damage, 1 point: damage to about 20% of the total leaf area, 2 point: damage to about 40% of the total leaf area, 3 point: damage to about 60% of the total leaf area, 4 point: severe damage, damage to more than about 80% of the total leaf area. [Table 2]

[0059] The hybrids had as little damage from corn earworms as the parental perennial buckwheat (FC). The hybrids showed higher insect resistance compared to perennial buckwheat, common buckwheat, and Dattan buckwheat.

[0060] <Aphid attachment> Various buckwheats were cultivated in the field using conventional methods, and the degree of attachment of naturally occurring aphids to the plant bodies was observed and evaluated by scoring. 0 points: no attachment; 1 point: attached to about 10% of the plants in the test plot; 2 points: attached to about 20% of the plants in the test plot; 3 points: attached to about 30% of the plants in the test plot; 4 points: attached to 40% or more of the plants in the test plot.

Table 3

[0061] The hybrid had as few aphid attachments as the parent perennial buckwheat (FC). The hybrid showed higher insect resistance compared to perennial buckwheat, common buckwheat, and Dattan buckwheat.

[0062] <Powdery mildew> Cultivated in a greenhouse using horticultural soil, the degree of infection with naturally occurring powdery mildew was observed and evaluated by scoring. 0 points: no infection; 1 point: about 20% of the plants in the test plot were infected; 2 points: about 40% of the plants in the test plot were infected; 3 points: about 60% of the plants in the test plot were infected; 4 points: 80% or more of the plants in the test plot were infected.

Table 4

[0063] The hybrid had a lower degree of powdery mildew infection than the parent species (FC, FT). The hybrid showed higher disease resistance compared to perennial buckwheat, common buckwheat, and Dattan buckwheat.

[0064] <Downy mildew> Cultivated in the field using conventional methods, the degree of infection with naturally occurring downy mildew was observed and evaluated by scoring. 0 points: no infection; 1 point: about 10% of the plants in the test plot were infected; 2 points: about 20% of the plants in the test plot were infected; 3 points: about 30% of the plants in the test plot were infected; 4 points: 40% or more of the plants in the test plot were infected.

Table 5

[0065] The hybrid has a disease incidence similar to that of the parental species (FT). The hybrid can confer powdery mildew resistance while maintaining its perennial nature. The hybrid showed higher disease resistance compared to the perennial buckwheat and common buckwheat.

[0066] Example 9: Resistance to pre-harvest sprouting In this example, the resistance to pre-harvest sprouting of the perennial buckwheat (Gene Bank JP number "JP41916"), common buckwheat ("Hitachi Autumn Buckwheat"), Dattan buckwheat ("Manten Kirari"), and the hybrid of the perennial buckwheat and Dattan buckwheat was investigated. In the following experiment, there were 3 replicates for each test plot, and the number of plants in each test plot was 10 or more. Cultivation was carried out in a greenhouse using conventional methods, and a pre-harvest sprouting assay (Petri dish germination test) was performed using fully mature seeds. Germination was carried out at 25°C. Pre-harvest sprouting was evaluated by scoring. 0 points: no germination, 1 point: germination in about 20% of the plants, 2 points: germination in about 40% of the plants, 3 points: germination in about 60% of the plants, 4 points: germination in 80% or more of the plants. [Table 6]

[0067] The hybrid has a pre-harvest sprouting tolerance similar to that of the parental perennial buckwheat (FC). The hybrid showed stronger pre-harvest sprouting tolerance compared to the perennial buckwheat and common buckwheat.

[0068] Example 10: Vegetative propagation test <Comparison of survival rates of single-node seedlings> Using pots for cell seedlings, single-node seedlings of common buckwheat ("Hitachi Autumn Buckwheat"), perennial buckwheat (Gene Bank JP number "JP41916"), and the hybrid of perennial buckwheat and Dattan buckwheat ("Manten Kirari") were planted. After 4 weeks of growth, the germination rate and survival rate of the seedlings were tested. The single-node seedlings were prepared by cutting the stem of the buckwheat plant, excluding the apical inflorescence and lateral branches at the tip, to a length of 4 cm so that the node (branching point) was located in the center. The presence or absence of survival was determined by the presence or absence of root ball formation. The results are shown in the graph of Figure 14. Seedlings that survived as a result of crossing with perennial buckwheat were obtained, and all common buckwheat plants died. Among the hybrids, only seedlings with original leaves survived, while in the hybrids, germination and survival were observed even in one-node seedlings without leaves, indicating that vegetative propagation using one-node seedlings is possible in the hybrids. <Survival rate of seedlings by type and part in hybrids> Since it was revealed that the hybrids can efficiently perform vegetative propagation, the survival rates of seedlings by type and part were compared. The vegetative propagation test of the hybrids was conducted on individuals after overwintering ("long seedlings") and young plants newly germinated from the ground ("short seedlings"). For the "tip seedlings", the part from the inflorescence-forming part of each plant to the base of the lateral branch was used. Also, for the "per plant", only the above-ground part was collected from the field and planted per plant in a pot without roots.

Table 7

[0069] As a result, in the long seedlings, survival was observed in the one-node seedlings of the main branch, and all died in the lateral branches, suggesting that the vegetative propagation ability of the lateral branches is lower compared to the main branch. Also, in the short seedlings, the one-node seedlings died, but the survival rates were high in the plants planted per plant and the tip seedlings.

Claims

1. A buckwheat plant obtained by crossing perennial buckwheat Fagopyrum cymosum with a buckwheat plant having no or trace rutinase activity.

2. The buckwheat plant according to claim 1, which is perennial.

3. The buckwheat plant according to claim 1 or 2, which is moisture-tolerant.

4. The buckwheat plant according to claim 1 or 2, which is drought-tolerant.

5. The buckwheat plant according to claim 1, which has moisture tolerance and one or more traits selected from the following: - The yield is 50% or more higher than that of common buckwheat. - It is drought-tolerant. - The seed shattering property is reduced or there is no seed shattering property. - The bitterness is reduced or there is no bitterness. - The rutinase activity is 30 nkat or less per 1 g of seeds excluding the husk. - It is perennial. - It has soil freezing tolerance. - It has disease resistance. - It has insect resistance. - It has resistance to ear sprouting. - It has a high survival rate in vegetative propagation.

6. The buckwheat plant according to claim 1, which is drought-tolerant and has one or more traits selected from the following: - The yield is 50% or more higher than that of common buckwheat. - It is moisture-tolerant. - The seed shattering property is reduced or there is no seed shattering property. - The bitterness is reduced or there is no bitterness. - The rutinase activity is 30 nkat or less per 1 g of seeds excluding the husk. - It is perennial. - It has soil freezing tolerance. - It has disease resistance. - It has insect resistance. - It has resistance to ear sprouting. - It has a high survival rate in vegetative propagation.

7. The buckwheat plant according to claim 1, which is perennial and has one or more traits selected from the following: - The yield is 50% or more higher than that of common buckwheat. - It is moisture-tolerant. - It is drought-tolerant. - The seed shattering property is reduced or there is no seed shattering property. - The bitterness is reduced or there is no bitterness. - The rutinase activity is 30 nkat or less per 1 g of seeds excluding the husk. - It has soil freezing tolerance. - It has disease resistance. - It has insect resistance. - It has resistance to ear sprouting. - It has a high survival rate in vegetative propagation.

8. A food product containing a part of the plant body of the buckwheat plant according to claim 1 or 2.

9. A method for producing a perennial buckwheat plant, comprising the step of crossing perennial buckwheat Fagopyrum cymosum with a buckwheat plant having no or trace rutinase activity.

10. In the obtained progeny plants, ​ In the first year of cultivation, selecting a plant that has sent out shoots from the base of the plant, or selecting a plant having two or more roots with a diameter of 1 cm or more, including the step of selecting a perennial plant, A method for producing a perennial buckwheat plant according to claim 9.

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