Breeding method of special rice for processing anti-aging retrogradation high-quality instant rice

Abstract

The invention provides a breeding method of special rice for processing anti-aging retrogradation high-quality instant rice, which belongs to the technical field of rice breeding, and comprises the following steps: introducing an anti-aging retrogradation character gene a of dug off-white endosperm into an improved rice variety through hybridization to obtain seeds which gather recessive genes a and other excellent character genes; the method comprises the following steps: taking recessive grey-white endosperm anti-aging retrogradation marker characters as selective markers, combining with anti-aging retrogradation and rehydration performance identification, carrying out multi-generation selfing to obtain soft rice strains with good anti-aging retrogradation and rehydration performance, and breeding soft rice strains with excellent comprehensive characters from the soft rice strains. The instant rice prepared by using the variety bred by the method under the condition of not doping any food additive is not aged and retrogradation, has excellent rehydration performance, and is beneficial to prolonging the shelf life of the product, reducing the technical production cost, improving the quality and stability of the product and making a brand.

Description

Technical Field

[0001] The present invention relates to the technical field of rice breeding, and particularly relates to a breeding method for a special rice variety for processing anti-aging and retrogradation-resistant high-quality instant rice. Background Art

[0002] Since more than 90% of the nutrients required by the human body, as well as rich proteins, fats, VB1, VA1, VE and various mineral trace elements, are contained in the rice endosperm, instant rice has become a key R & D product in the global staple food industrialization development as early as during World War II in the early 1940s due to the demand for military staple foods, and gradually turned to civilian commercial development and entered the market in the 1980s. With the improvement of living standards, the acceleration of work rhythms, and the gradual upgrading of consumption concepts, instant rice that is convenient, fast, and nutritious has been favored by more and more consumers. The introduction of relevant standards for instant rice (GB / T 31323-2014) has strongly promoted the booming development of the instant rice industry.

[0003] However, during the industrial development process of instant rice, problems such as aging and retrogradation, and poor rehydration still exist, resulting in hardening and caking of rice grains, deterioration of taste quality, etc., which affect consumers' recognition and market competitiveness. In order to overcome technical problems such as aging and retrogradation, and poor rehydration of instant rice, currently, at home and abroad, research and incorporation of some food additives are mostly adopted for regulation, and good results have been achieved. However, the incorporation of some food additives in the processing of instant rice may increase the risk of product safety. With the continuous improvement of consumers' awareness of food safety risks, due to concerns about the safety of instant rice incorporated with food additives, the willingness to purchase and consume instant rice products incorporated with food additives will be reduced. Moreover, adding food additives will not only increase the technical and raw material costs of enterprises, but also lead to product safety risks and food safety accidents caused by imitation and illegal addition of products, endangering the health and interests of consumers. In particular, the negative impact of food additives on human health is hidden and latent. People cannot detect it in time through sensory inspection and take preventive measures. At the same time, modern food toxicology has also found that some food additives originally considered safe may also have chronic toxicity and the risk of causing deformities, mutations, and cancers, making the chemical properties of food additives themselves may turn into uncertain factors affecting food safety under specific conditions, which will increase the supervision workload. Therefore, how to explore gene resources from existing excellent rice germplasm resources from the aspect of biological breeding, which can prevent instant rice from aging, hardening, caking, and deteriorating in quality during processing and storage, and select special rice varieties suitable for processing high-quality instant rice with anti-aging and retrogradation resistance and good rehydration performance without the need to add food additives is of great significance for eliminating or reducing the use of food additives and promoting the healthy and stable development of the instant rice industry.

[0004] As a convenient rice for industrialized staple food production, the physicochemical properties of its processed taste are essentially different from those of home-cooked steamed rice, mainly reflected in the recrystallization and aging of endosperm starch and the rehydration during consumption. However, the mechanism of aging and retrogradation of convenient rice is still unclear internationally. Previous studies have shown that the quality characteristics of germplasm resources varieties are the most important factors affecting the processing quality of convenient rice, and there are significant differences in the effects of different quality types on the taste quality of convenient rice. In order to accurately evaluate the numerous existing paddy varieties currently being promoted and select high-quality raw material varieties suitable for making convenient rice, scholars at home and abroad have conducted a large number of studies on the adaptability characteristics of convenient rice processing raw materials with the help of modern experimental detection methods. They all believe that the starch tissue, structure, and gelatinization characteristics of rice endosperm have an important impact on the processing quality of convenient rice. Therefore, controlling the aging and retrogradation of convenient rice through raw material varieties and improving the taste quality is the best way. The reason why soft rice is suitable for making high-quality convenient rice is that soft rice has a high amylopectin content, and amylopectin is distributed in a three-dimensional space, making it difficult to form hydrogen bonds and inhibiting the recrystallization and aging of starch molecules. Especially, some soft rice has a high content of short-chain A chains in endosperm amylopectin, which is conducive to the dissolution of long-chain B, forming a better and more stable gel network structure, making the soft rice have better elasticity. In addition, the high content of dissolved solids in high-quality soft rice is conducive to the formation of a protective film, resulting in softer, smoother, and non-sticky rice. However, perhaps due to the fact that no varieties with good anti-aging and retrogradation properties and good rehydration performance, suitable for making high-quality convenient rice, have been discovered and screened yet, the technical problems such as aging and retrogradation caused by starch recrystallization and poor rehydration performance of convenient rice have not been fundamentally solved. In order to minimize aging and retrogradation, improve the rehydration and taste quality, and shelf life of convenient rice to the greatest extent, convenient rice processing enterprises more or less add different types of food additives.

[0005] Yunnan is not only the largest genetic and ecological diversity center and natural treasure house of rice varieties in China, but also the enrichment center of excellent rice germplasm in China, retaining the most abundant and diverse soft rice germplasm resources in the world, and is the origin of authentic soft rice in the world, due to its unique geographical and ecological environment conditions and living habits. In particular, Yunnan's soft rice germplasm resources, as a type of indica rice unique to Yunnan, have been rich in "favorable" genetic gene resources after nearly 10,000 years of evolution and selection. Therefore, the exploration and utilization of Yunnan's soft rice germplasm resources have always been of great concern to the rice breeding scientific community at home and abroad. Since the mid-1970s, although relevant universities and research institutions in Yunnan have introduced the soft rice genes of Yunnan's local soft rice old varieties such as Haomuxi and Haopi into IR24 and other short-stem, high-resistance rice varieties, and successfully bred a batch of high-quality rice varieties such as Dianrui 408, Diantun 502, Wendao No. 1, and Wendao No. 2, the phenomenon of rice resurrection every other day is still prominent in these varieties, and the taste quality is not as good as the local soft rice old varieties. In the breeding of soft japonica rice, Japan used the high-quality japonica rice variety Koshihikari for mutagenesis in the 1980s and successfully bred a number of soft rice varieties with an amylose content of about 10%, such as Milky Queen. The predecessors used the Japanese soft rice variety Kanto 194 as a japonica soft rice gene donor and successfully hybridized and bred a number of japonica soft rice variety materials with excellent taste quality. Some scholars used these soft rice variety resources as experimental materials to conduct research on the adaptability of instant rice, and believed that japonica soft rice varieties are currently one of the most suitable raw material varieties for making instant rice. However, there are no reports on the production and processing of instant rice with japonica soft rice without adding food additives. Summary of the invention

[0006] In view of the technical problems existing in the background technology, the present application provides a breeding method for anti-aging and rejuvenating high-quality instant rice processing rice to solve the technical problem of the shortage of high-quality instant rice processing rice varieties.

[0007] In order to achieve the above object, the technical solution of the present invention is as follows: A breeding method for anti-aging and rejuvenating high-quality instant rice processing rice, comprising the following steps: S1. A rice germplasm resource variety II having the off-white endosperm anti-aging reversion trait gene a is hybridized with B rice improved varieties III, and the donor variety IV and the recipient variety V having the recessive off-white endosperm anti-aging reversion trait gene a with the same allele are screened out through the allelism and combining ability determination of the anti-aging reversion trait gene a. S2, hybridizing the donor variety IV with the recipient variety V to obtain a hybrid seed VI, and self-pollinating the hybrid seed VI to obtain a homozygous phenotypic seed VII having the gene a for the gray-white endosperm anti-aging regeneration trait; S3. Sow Seed VII, using the trait of having a grayish-white endosperm with anti-retrogradation regenerative property as a selection marker, and conduct multi-generation self-cross selection to obtain C soft rice lines VIII with anti-retrogradation regenerative property, good rehydration performance, and stable traits. S4. Using agronomic traits as indicators, select D high-quality soft rice lines IX from the C soft rice lines VIII, which have both anti-retrogradation regenerative property, excellent rehydration performance, and genetic stability, as well as excellent high-yielding, adaptability, and resistance characteristics.

[0008] In the above breeding method, A, B, C, and D are all positive integers respectively.

[0009] In the above breeding method, the rice germplasm resource variety II is screened from the old varieties of high-quality soft rice resources widely collected at home and abroad and their derived varieties I, specifically by conducting anti-retrogradation regenerative identification on variety I. It can be understood that the collected variety I refers to the rice germplasm resource variety containing the anti-retrogradation regenerative trait gene a, including the endosperm transparent soft rice germplasm resource variety with the phenotypic trait of the anti-retrogradation regenerative trait gene a already expressed and the rice germplasm resource that does not yet express this trait but already contains the anti-retrogradation regenerative trait gene a; specifically, the gene a in variety I refers to the gene "hidden" in the rice germplasm resources at home and abroad or the gene that is inherently hidden in the rice germplasm resources and has not been discovered yet, rather than the foreign introduced gene outside the rice germplasm resources.

[0010] Currently, the types of global soft rice germplasm resource varieties are diverse, the genetic backgrounds are complex, and there are numerous genes controlling the retrogradation and regeneration traits. In addition, the cooking and eating quality of rice is not only affected by the amylose content in the endosperm, but also controlled by the structures of amylose and amylopectin, as well as other organizational structures such as proteins and fats. Therefore, there are significant differences in the anti-retrogradation regenerative property and eating quality among varieties with the same or similar amylose content but different genetic backgrounds. Even among different varieties with the same or similar amylose content from the same genetic background, there are often obvious differences in the anti-retrogradation regenerative performance and eating quality of the cooked rice. Given that the soft rice germplasm resources, especially the Yunnan soft rice germplasm resources, have undergone nearly ten thousand years of evolution and selection, they may contain rich gene resources with excellent anti-retrogradation regenerative property and rehydration performance. Therefore, the present invention first conducts anti-retrogradation regenerative identification on the soft rice germplasm resource varieties I with complex and rich genetic backgrounds, in order to discover and screen out the soft rice germplasm resource varieties II carrying the excellent anti-retrogradation regenerative gene a (using the first letter a of the English word "aging" for the anti-retrogradation regenerative trait gene symbol). Fortunately, the inventor successfully discovered a recessive anti-retrogradation regenerative trait gene a from a large number of collected high-quality soft rice germplasm resource materials with anti-retrogradation regenerative characteristics, which is manifested as a grayish-white endosperm, and using this trait can be selected and purified in the early generation of hybridization, which is beneficial to accelerating the breeding efficiency.

[0011] Preferably, in the above breeding method, the rice germplasm resource variety II is one or more of Haopi, Haomulü, Haoerwanghanduo, WR05-825, WR05-1080, WR06-887, WR06-1238, WR07-2188, WR07-2368.

[0012] More preferably, the donor variety IV selected from the rice germplasm resource variety II is WR07-2368.

[0013] In the above breeding method, the high-quality rice variety III refers to an excellent rice germplasm resource variety that has aggregated comprehensive excellent trait genes such as high yield, resistance, adaptability, eating quality, combining ability, and restoring ability, and has been widely promoted and used on a large scale. Preferably, the high-quality rice variety III is selected from soft rice restorer line materials with the genetic background of Yunnan fragrant soft rice germplasm resources and transparent endosperm, and specifically can be one or more of Wenhui 206, Wenhui 247, Wenhui 184, Wenhui 163, Wenhui 221, Wenhui 242, Wenhui 264, Wenhui 324, Wenhui 305, Wenhui 499, Wenhui 791, Wenhui 821, Wenhui 1021, Wenhonghui 628.

[0014] More preferably, the receptor variety V selected from the high-quality rice variety III is Wenhui 247. Wenhui 247 has an allelic anti-aging and retrogradation trait gene a locus equivalent to that of the rice germplasm resource variety II, and has advantages such as strong restoring ability and combining ability, resistance to rice blast, long flowering period, good outcrossing habit, and excellent eating quality.

[0015] In the above breeding method, in step S2, through hybridization, the gene a of the donor variety IV is introduced into the receptor variety V, so that the recessive grayish-white endosperm anti-aging and retrogradation trait gene a and the high combining ability and other excellent trait genes of the receptor variety are integrated into one, and a hybrid seed VI that aggregates the recessive anti-aging and retrogradation trait gene a and other excellent trait genes such as high yield, high resistance, wide adaptability, and strong combining ability of both parents is obtained. The hybridization in the present invention is a conventional rice hybridization technique, and has the following operation key points: First, according to the biological characteristics of the male parent and the female parent, cultivation technical measures are taken to make the male and female parents bloom at the same time; second, through external means such as artificial emasculation of the female parent (when the female parent is a sterile line, artificial emasculation is not required) and artificial pollination, the pollen of the male parent is transmitted to the stigma of the female parent for hybridization pollination to obtain hybrid rice seeds.

[0016] In the above breeding method, in step S2, the heterozygous seeds VI are further planted and self-crossed to separate and recombine the gene a for the anti-aging and retrogradation trait of the off-white endosperm and other excellent trait genes, and purify the gene a for the anti-aging and retrogradation trait, so as to form and obtain the phenotypic seeds with the target trait genes. The specific operation is as follows: After the seeds are mature, they are harvested in time and dried. After the moisture content of the seeds is lower than 13%, the seeds are shelled and observed, and the seeds are selected by taking the recessive off-white endosperm anti-aging and retrogradation trait marker as the selection marker, so as to obtain the phenotypic seeds VII (aa) with the homozygous recessive gene a for the off-white endosperm anti-aging and retrogradation trait.

[0017] In the above breeding method, in step S3, plant selection is carried out in the same way as in step S2. By shuttle planting in different regions, continuous generation addition and separation selection are carried out to purify the target trait gene a and other excellent trait genes of the selected individual plants. After multiple generations of self-crossing, the stable lines are identified for anti-aging and retrogradation, rehydration performance, and high yield, etc., and one or more high-quality soft rice lines VIII with stable traits of anti-aging and retrogradation and good rehydration performance can be obtained. Preferably, the number of generations of multiple generations of self-crossing is 6-8 generations.

[0018] In the above breeding method, in step S4, through multi-point high-yield, adaptability, stability, and resistance identification tests, high-quality soft rice lines IX with excellent anti-aging and retrogradation, rehydration performance, and genetic stability, as well as excellent agronomic traits of high yield, adaptability, and resistance are selected from the soft rice lines VIII.

[0019] Preferably, in the above breeding method, the following steps are further included: Through field productivity and combining ability identification tests, the soft rice lines IX are further screened to obtain high-quality rice seeds X with excellent anti-aging and retrogradation, rehydration performance, the highest yield, the strongest combining ability, the best resistance and high yield. The selected rice seeds can be used as high-quality varieties for the special rice for convenient rice processing. For example, in the embodiment of the present invention, a high-quality soft rice variety WR14-686 (named Wenbaihui 686) with excellent anti-aging and retrogradation, rehydration performance, high yield, high resistance, wide adaptability, and strong combining ability is successfully selected from multiple high-quality soft rice lines IX.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The special rice for convenient rice processing selected by the method of the present invention has excellent anti-aging and retrogradation and rehydration performance. When making convenient rice with it, without adding any food additives, the convenient rice will not age and retrograde, has good rehydration performance, and extends the shelf life, can effectively overcome the dependence on food additives, reduce the production technology cost and the risk of product safety, and is beneficial to the competitiveness of the product in the market and the brand building.

[0021] (2) The present invention has pioneered the successful exploration of genes with recessive anti-aging retrogradation and excellent rehydration performance from high-quality soft rice germplasm resources in Yunnan, China, for breeding special-purpose rice for anti-aging retrogradation high-quality instant rice, enriching the types of high-quality special-purpose rice in China and laying a good germplasm resource foundation for the healthy and stable development of the instant rice industry.

[0022] (3) The present invention introduced the discovered recessive anti-aging retrogradation gene into high-quality rice seeds, and successfully promoted the production of special-purpose rice varieties for processing high-quality instant rice with anti-aging retrogradation and without the need to incorporate food additives. This not only enriches the types of special high-quality rice in China, but also changes the single situation in the current global instant rice market where products may contain food additives to prevent aging retrogradation and overcome poor rehydration performance, meeting the diverse needs of consumers for instant rice varieties. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the present invention, the drawings used in the present invention will be briefly introduced below. Obviously, the following described drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0024] Figure 1 It is a flowchart of the method for breeding special-purpose rice for processing high-quality instant rice with anti-aging retrogradation in the embodiments of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0025] The embodiments of the technical solutions of the present invention will be described in detail below with reference to the drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention, so they are only examples and cannot be used to limit the protection scope of the present invention.

[0026] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "comprising" and "having" and any variations thereof in the specification and claims of this application and the above description of the drawings are intended to cover non-exclusive inclusion.

[0027] In the present invention, the term "aging resistance and regrowth property" refers to the performance of the instant rice made without adding any food additives at normal temperature (25°C) and refrigerated temperature (4°C) environments at 1, 12, 24 hours, 7, 14, 21, 30 days, 2 months, 3 months, and 6 months, as well as the sensory taste quality after rehydration of the dehydrated instant rice. It is manifested in that the rice grains are crystal clear, elastic, soft, smooth, shiny, non-sticky, non-caking, and non-undercooked. The taste quality after rehydration can return to the original state, and it is mainly quantitatively analyzed and comprehensively evaluated by rice quality physical and chemical indexes, taste value, sensory taste value, retrogradation value, hardness value, and rehydration performance (rehydration time, rehydration rate, and α-degree value).

[0028] In the present invention, the term "identification of aging resistance and regrowth property" refers to the identification of the detection means and methods for accurately quantitatively analyzing and evaluating the aging resistance and regrowth property and rehydration performance status by referring to methods such as "Inspection of grain and oils - Sensory evaluation method for cooking and eating quality of paddy and rice" (GB / T 15682 - 2008), "Determination of pasting properties of rice and rice flour - Rapid visco analyzer method" (GB / T 24852 - 2010), "Quality of edible rice varieties" (NY / T 593 - 2002), etc., as well as instruments and equipment such as taste meters and texture analyzers. In the present invention, the production of rice and its sensory taste identification are carried out by referring to "Inspection of grain and oils - Sensory evaluation method for cooking and eating quality of paddy and rice" (GB / T 15682 - 2008). The analysis of rice quality physical and chemical indexes is carried out in accordance with "Quality of edible rice varieties" (NY / T 593 - 2002). The identification of the retrogradation value is carried out according to the method of "Determination of pasting properties of rice and rice flour - Rapid visco analyzer method (RVA)" (GB / T 24852 - 2010). The taste value is measured by using a Japanese STA 1B rice taste meter, and the hardness value is measured by a texture analyzer TPA. The rehydration performance mainly measures the rehydration time, rehydration rate, and α-degree value, and the measurement method refers to and draws on previous research (Research on the quality evaluation method and raw material adaptability of quick-frozen instant rice, Huang Meihua, 2013; Determination of pretreatment process parameters of freeze-dried instant rice, Pu Biao, 2007; Theory and methods of grain quality testing, Tian Jichun, 2006). When measuring samples with instruments and equipment, repeat 3 times and take the average value.

[0029] In the present invention, having anti-aging and regrowth properties means that after paddy rice is matured and dried (water content ≤ 13%), the amylose content is 10 ± 1.0%, the gel consistency is ≥ 90 mm, and the alkali spreading value is ≥ 6.0. For the instant rice made therefrom, without adding any food additives or modifiers, when stored at room temperature (about 25.0°C) and refrigerated (about 4.0°C), as long as the water content of the rice is maintained at 60.0%, within 6 months, it will not recrystallize due to starch again. After reheating for 2 minutes during consumption, its taste quality is the same as that of freshly cooked rice cooled at room temperature within 1 hour, and the changes in taste value, retrogradation value, hardness value, and sensory taste quality value do not exceed 5.0%. Good rehydration performance means that the taste quality of the dehydrated instant rice after rehydration can quickly return to its original state, manifested as the rice grains being crystal clear, elastic, smooth, shiny, non-sticky, non-caking, and not undercooked.

[0030] In the present invention, the term "food additive" refers to artificial synthetic or natural substances other than those inherent in rice itself that are incorporated during the production process of instant rice in order to slow down the aging and regrowth of instant rice and improve product quality, also known as modifiers.

[0031] Problems such as the aging and regrowth of instant rice due to recrystallization, poor rehydration performance resulting in caking and undercooking, and deterioration of taste quality are worldwide problems. In view of this problem, at home and abroad, there has been a shift to the research, development, and use of food additives. However, using food additives to regulate and improve problems such as the aging and regrowth of instant rice also brings several issues that cannot be ignored: First, it will increase the potential safety risks of the product. Second, with the increasing awareness of food safety risks among today's consumers, due to concerns about the safety of food additives added to instant rice, it will also reduce the willingness to purchase and consume instant rice products with any food additives added. Third, incorporating food additives will not only increase the technical and raw material costs of enterprises, but also lead to product safety risks and food safety accidents caused by illegal imitation and addition of products, increasing the regulatory workload, especially harming the health and interests of consumers.

[0032] In view of the current situation in the industrial development of instant rice, where there is a lack of high-quality special rice varieties for instant rice processing, and there is no high-quality special raw material rice variety suitable for anti-aging and regrowth without the need to add food additives, resulting in technical problems such as aging and regrowth, poor rehydration performance, hardening, caking, and undercooking of instant rice processing products, and deterioration of taste quality. At the same time, in order to avoid problems such as food safety risks brought by food additives, reducing consumers' willingness to purchase and consume, and increasing product technical and raw material input costs, the present invention provides a breeding method for a special rice for high-quality anti-aging and regrowth instant rice processing. The rice variety obtained by the method of the present invention can be used to produce instant rice with zero addition, and on the basis of ensuring the quality of instant rice, it eliminates the dependence on food additives.

[0033] Such asFigure 1 As shown in Figure 1 , an embodiment of the present invention provides a breeding method for a special rice variety for processing anti-aging and rehydration high-quality instant rice, which includes the following steps: (1) Widely collect high-quality soft rice germplasm resources and their derivative varieties I, and identify and screen out rice germplasm resource varieties II carrying the anti-aging and rehydration trait gene a of grayish-white endosperm through the identification of anti-aging and rehydration properties and rehydration performance; (2) Hybridize the rice germplasm resource variety II with the good rice variety III with the anti-aging and rehydration trait gene a of grayish-white endosperm, and screen out the donor variety IV and the receptor variety V with the recessive anti-aging and rehydration trait gene a of grayish-white endosperm with the same allelism through the determination of the allelism and combining ability of the anti-aging and rehydration trait gene a; (3) Hybridize the donor variety IV with the receptor variety V to integrate the recessive anti-aging and rehydration trait gene a and excellent trait genes such as high yield, resistance, wide adaptability, and strong combining ability into one, so as to obtain a hybrid seed VI with the recessive anti-aging and rehydration trait gene a and excellent trait genes such as high yield, resistance, wide adaptability, and strong combining ability; (4) Self-cross the hybrid seed VI to separate and recombine the target trait gene a and other excellent trait genes, and form a pure phenotypic seed VII with the recessive anti-aging and rehydration trait gene a; (5) Plant the seed VII (aa), and take shelling observation. Using the anti-aging and rehydration property marker trait of grayish-white endosperm as the selection marker, select the method consistent with the marker color of the donor parent IV for multi-generation self-crossing selection, and continuously purify the comprehensive excellent trait genes of the selected individual plants; After multi-generation self-crossing, obtain a high-quality soft rice line VIII with stable traits, anti-aging and rehydration properties, and good rehydration performance; (6) Through multi-point high-yield, adaptability, stability, and resistance identification tests, select a high-quality soft rice line IX with stable heredity, excellent anti-aging and rehydration properties, and excellent comprehensive agronomic traits such as high yield, adaptability, and resistance from the soft rice line VIII; (7) Through field productivity and combining ability identification tests, select a high-quality soft rice variety X with excellent anti-aging and rehydration properties, high yield, high resistance, wide adaptability, and strong combining ability from the high-quality soft rice line IX.

[0034] Further, in some embodiments, the rice germplasm resource variety II is selected from Yunnan soft rice varieties, such as Haopi, Haomülü, Hao'erwanghanduo, WR05-825, WR05-1080, WR06-887, WR06-1238, WR07-2188, WR07-2368, etc.; and the corresponding high-quality rice seeds III are selected from restorer line materials with the genetic background of Yunnan aromatic soft rice germplasm resources and transparent endosperm, such as Wenhui 206, Wenhui 247, Wenhui 184, Wenhui 163, Wenhui 221, Wenhui 242, Wenhui 264, Wenhui 324, Wenhui 305, Wenhui 499, Wenhui 791, Wenhui 821, Wenhui 1021, Wenhonghui 628, etc.

[0035] The applicant of the present invention has been engaged in the research on the exploration, breeding, processing and utilization of Yunnan fragrant rice germplasm resources for more than 30 years. Not only has a batch of new genes and new resources with diverse hull colors of rice seeds and endosperm colors of rice been successfully discovered, but also a batch of soft rice materials with diverse taste quality types have been successfully excavated, especially soft rice germplasm resources that are resistant to aging and hardening back, that is, they are not easily aged and hardened back under normal temperature (about 25°C) or refrigerated (about 4°C) conditions after cooking. In view of China's proposal to increase the development of instant rice and the technical problems faced by instant rice, the inventor combines the advantages of the soft rice germplasm resources mastered by himself and proposes to introduce the anti-aging and hardening-back trait genes independently discovered into high-quality seeds with excellent taste quality and allelism, so as to breed processing special rice varieties that are resistant to aging and hardening back, have good rehydration performance, and are suitable for making high-quality instant rice without adding any food additives.

[0036] The processing special rice for high-quality instant rice selected by the method of the present invention, such as Wenbaihui 686, has the advantages of high yield, strong resistance, wide adaptability and disease resistance. Moreover, it can be stored for a long time (more than 6 months) at normal temperature or refrigerated conditions without aging and hardening back, and can maintain the same taste quality as the newly cooked rice within 1 hour after cooking, cooling and steaming, extend the shelf life, and the rehydration time of the dehydrated instant rice made from it is short, not easily aged, caked or undercooked, and the taste quality can be restored to the original state. Without using any food additives at all, it effectively solves the problems of the recrystallization, aging and hardening back of instant rice and the deterioration of taste quality.

[0037] Some specific embodiments are listed below. It should be noted that the embodiments described below are exemplary and are only used to explain the present invention, and should not be construed as a limitation of the present invention. For those not specified in the embodiments regarding specific techniques or conditions, they shall be carried out according to the techniques or conditions described in the literature in the art or according to the product specifications. For reagents or instruments not specified by the manufacturer, they are all conventional products that can be obtained through commercial purchase.

[0038] In the following examples, the scented soft rice three-line sterile lines Haoxiang 24A, Wenxiang 28A, Zhuangxiang 2051A, and the scented soft rice restorer lines Wenhui 206, Wenhui 247, Wenhui 184, Wenhui 163, Wenhui 221, Wenhui 242, Wenhui 264, Wenhui 324, Wenhui 305, Wenhui 499, Wenhui 791, Wenhui 821, Wenhui 1021, Wenhonghui 628 are sterile lines and restorer lines successfully selected by the Wenshan Academy of Agricultural Sciences. They have obtained plant variety rights and are preserved in the germplasm bank resources of the Wenshan Academy of Agricultural Sciences. They can be introduced from this germplasm bank or from other germplasm resource banks. The two-line sterile line Y58S was selected by the Hunan Hybrid Rice Research Center, and Long 638S and Jing 4155S were selected by the Hunan Yahua Seed Industry Science and Technology Research Institute. They were all introduced from Sichuan Longping High-Tech Seed Industry Co., Ltd. The hybrid rice control variety Lingheyou 78 is a hybrid rice combination selected by Yunnan Hepu Agricultural Technology Co., Ltd. and was introduced from Yunnan Hepu Agricultural Technology Co., Ltd. Dianrui 408, Dianlong 201, Dianrui 449, Diantun 502, Wendao 1 (Babao Fragrance), Wendao 2, Denong 203, Denong 211, Denong 204, Denong 206, Deyou 2, Linyou 1458, Banna 15, Banna 21, Hongyou 1, Hongyou 2, Hongyou 3, Hongyou 4, Hongyou 5, Hongdao 6, Wendao 8, Wendao 11 are scented soft rice conventional rice varieties selected by the Yunnan Academy of Agricultural Sciences, the agricultural academies of Wenshan and Honghe prefectures, and the agricultural scientific research institutes of Dehong, Xishuangbanna, Lincang and other prefectures and cities, and can be introduced from the breeding units. Local germplasm resource varieties such as Haopi, Haojiehai, Haomulu, Haomuxi, Haomuxi, Haoerwanghange, Haodilahao, Babao Valley, Huangbansuo, Haoanmen, Haoannong, Haogongxin, Haobayuan, Haomoya, Haohaonen, Haojiehai, Haoanwang, Haoannongmiezan, Haonuobixiang, Haobawenwan, etc. are scented soft rice local variety resources collected by the Wenshan Academy of Agricultural Sciences from Yunnan and its surrounding areas. 10 well-known domestic japonica soft rice improved varieties such as Longdao 12, Longjing 38, Songjing 15, Daohuaxiang 2 (Wuyoudao 4), Yunjing 20, Yunjing 37, Nanjing 46, Nanjing 5055, Nanjing 9108, Ningjing 42 were introduced from Yunnan Agricultural University (they can also be introduced from the breeding units). 10 foreign famous high-quality rice varieties and their derivative varieties such as Jasmine85, KDML105, Basimati-136, Basimati-370, Basimati-6813, Yunhui 290, Guandong 194, Koshihikari, Nipponbare, Akita Komachi were introduced from Yunnan Agricultural University and the Yunnan Academy of Agricultural Sciences.These 38 high-quality soft rice strain materials, namely WR05-816, WR05-825, WR05-864, WR05-868, WR05-877, WR05-882, WR05-889, WR05-890, WR05-894, WR05-896, WR05-1007, WR05-1080, WR06-616, WR06-645, WR06-887, WR06-899, WR06-913, WR06-1080, WR06-1082, WR06-1112, WR06-1236, WR06-1238, WR07-1247, WR07-1307, WR07-1816, WR07-1825, WR07-1866, WR07-1868, WR07-1880, WR07-1984, WR07-1989, WR07-2089, WR07-2188, WR07-2289, WR07-2296, WR07-2307, WR07-2365, WR07-2368, are all hybrid offspring materials selected by the Wenshan Academy of Agricultural Sciences through cross-breeding with Yunnan local soft rice varieties as the soft rice gene donor varieties and soft rice improved varieties. They are preserved in the germplasm resource library of the Wenshan Academy of Agricultural Sciences and can be introduced from this germplasm library. Among them, 12 strains, namely WR05-816, WR05-825, WR05-864, WR05-868, WR05-877, WR05-882, WR05-889, WR05-890, WR05-894, WR05-896, WR05-1007, WR05-1080, use the Yunnan local high-quality soft rice variety resource Haomülu as the female parent and the Yunnan soft rice improved variety Dianrui 408 with the genetic background of Yunnan local high-quality soft rice variety resources as the male parent for hybridization, and continuously self-purify and select in Wenshan and Sanya for five consecutive years until F. 8 , and successfully selected high-quality soft rice strains in August 2009. 10 strains, namely WR06-616, WR06-645, WR06-887, WR06-899, WR06-913, WR06-1080, WR06-1082, WR06-1112, WR06-1236, WR06-1238, use the Yunnan local high-quality soft rice variety resource Haopi as the female parent and the Yunnan soft rice improved variety Wendao 2 with the genetic background of Yunnan local high-quality soft rice variety resources as the male parent for hybridization, and continuously self-purify and select in Sanya and Wenshan for five consecutive years until F 8, high-quality soft rice lines were successfully selected in April 2010. The 16 lines of WR07-1247, WR07-1307, WR07-1816, WR07-1825, WR07-1866, WR07-1868, WR07-1880, WR07-1984, WR07-1989, WR07-2089, WR07-2188, WR07-2289, WR07-2296, WR07-2307, WR07-2365, and WR07-2368 were hybridized with the high-quality local soft rice variety resource variety Haomulv in Yunnan as the female parent and the Yunnan soft rice improved variety Dianlong 201 with the genetic background of high-quality local soft rice variety resources in Yunnan as the male parent. In Wenshan and Sanya, through continuous five-year generation acceleration and purification line selection to F 8 , high-quality soft rice lines were successfully selected in August 2010.

[0039] Example 1 A breeding method for a special rice for processing anti-aging and retrogradation-resistant high-quality instant rice, specifically including the following steps: 1. Exploration and screening of rice germplasm resource varieties carrying the anti-aging and retrogradation-resistant trait gene a.

[0040] Collect high-quality soft rice germplasm resources and their derivative varieties at home and abroad extensively, specifically including: Haopi, Haojiehai, Haomülü, Haomuxi, Haomuxi, Haoerwanghange, Haodilahao, Babao Valley, Huangbansuo, Hao'anmen, Hao'annong, Hao Gongxin, Hao Bayuan, Hao Moya, Hao Haonen, Hao Jiehai, Hao Anwang, Hao'annongmiezan, Haonuobixiang, Hao Bawenwan, Dianrui 408, Dianlong 201, Dianrui 449, Diantun 502, Wendao 1, Wendao 2, Denong 203, Denong 211, Denong 204, Denong 206, Deyou 2, Linyou 1458, Banna 15, Banna 21, Hongyou 1, Hongyou 2, Hongyou 3, Hongyou 4, Hongyou 5, Hongdao 6, Wendao 8, Wendao 11, Longdao 12, Longjing 38, Songjing 15, Daohuaxiang 2, Yunjing 20, Yunjing 37, Nanjing 46, Nanjing 5055, Nanjing 9108, Ningjing 42, Jasmine85, KDML105, Basimati-136, Basimati-370, Basimati-6813, Yunhui 290, Guandong 194, Koshihikari, Nipponbare, Akita Komachi, WR05-816, WR05-825, WR05-864, WR05-868, WR05-877, WR05-882, WR05-889, WR05-890, WR05-894, WR05-896, WR05-1007, WR05-1080, WR06-616, WR06-645, WR06-887, WR06-899, WR06-913, WR06-1080, WR06-1082, WR06-1112, WR06-1236, WR06-1238, WR07-1247, WR07-1307, WR07-1816, WR07-1825, WR07-1866, WR07-1868, WR07-1880, WR07-1984, WR07-1989, WR07-2089, WR07-2188, WR07-2289, WR07-2296, WR07-2307, WR07-2365, WR07-2368. Use the above 100 varieties as experimental materials to conduct anti-aging retrogradation identification, in order to discover and screen out the rice germplasm resource varieties carrying the gene a for anti-aging retrogradation trait. The specific operations are as follows: From April to May 2012, at the experimental base of the Wenshan Prefecture Academy of Agricultural Sciences in Yunnan Province, according to the rice samples required for the aging retrogradation identification test and in order to reduce the test errors brought by the possible influence of the cultivation environment on the quality of the rice samples of the planting test materials, the planting plot area of each variety material participating in the test is 26.8m 2, a randomized block design was adopted without replication. Since most of the tested local old soft rice varieties are photosensitive varieties that flower and pollinate in late September, the heading, flowering and pollination period of the test materials was determined to be late September. All other tested materials, especially non-photosensitive tested varieties, were sown in stages from April to May according to the whole growth period of each variety to ensure that all tested materials headed, flowered and pollinated in late September. The experimental water and fertilizer management was carried out according to the local rice planting management level. When it matured in mid-October, it was harvested and dried in time. After drying for 2 months for ripening and stabilization, physicochemical analysis of rice quality, RVA and taste meter analysis as well as sensory taste evaluation were carried out. The local old soft rice variety Haopi was used as the control for the sensory taste evaluation. Calculated according to the allowable error rate within 5.0%, those with a taste quality score lower than the control by 5.0% and above, the comprehensive score of the taste meter is basically consistent with the sensory taste quality evaluation, the amylose content is about 10.0%, the gel consistency is ≧90mm, the alkali spreading value is ≧6.0, and the retrogradation value is less than or close to the control were selected as the primary selection criteria.

[0041] The test and identification results showed that 42 varieties such as Haopi, Haomolv, Haerwanghan Duo, Denong 206, Nanjing 42, WR05-825, WR06-887, WR07-1866, WR07-2188 reached the standards in the physicochemical analysis of rice quality. There were 38 variety materials with retrogradation values less than or close to the control (-0.24 / Pa.s), such as Haopi, Haomolv, Haerwanghan Duo, Denong 206, Nanjing 42, WR05-825, WR06-887, WR07-1866, WR07-2188. There were 30 varieties with sensory taste scores close to or higher than the control Haopi (92.4 points), such as Haomolv, Haerwanghan Duo, Denong 206, Yunhui 290, WR05-825, WR06-887, WR07-1866, WR07-2188. In terms of the physicochemical analysis of rice quality reaching the selected standards, the retrogradation value was less than or close to the control, the comprehensive taste value of the taste meter test was basically consistent with the sensory taste score, and the score was close to or higher than the control Haopi (sensory taste score 92.4 points), there were 17 varieties such as Haomolv, Haerwanghan Duo, Denong 206, WR05-825, WR05-1080, WR06-887, WR06-1112, WR06-1238, WR07-1307, WR07-1816, WR07-1825, WR07-1866, WR07-1984, WR07-1989, WR07-2188, WR07-2307, WR07-2368. Five materials such as Yunhui 290 had relatively high taste scores. Especially, the sensory taste score of Yunhui 290 reached 94 points, but the amylose content was as high as about 16%, and the retrogradation value was as high as above 0.16 / Pa.s after standing for 24 hours after cooling, so it was eliminated.

[0042] The anti-aging regeneration and rehydration performance of 18 selected materials (i.e., Haopi, Haomülü, Haoerwanghanduo, Denong 206, WR05-825, WR05-1080, WR06-887, WR06-1112, WR06-1238, WR07-1307, WR07-1816, WR07-1825, WR07-1866, WR07-1984, WR07-1989, WR07-2188, WR07-2307, WR07-2368) were identified. The identification results showed that the results of the taste meter test were basically consistent with the sensory taste identification results, and the taste scores were above 88 points. Among them, the taste scores of 12 variety materials such as Haopi, Haomülü, Haoerwanghanduo, WR05-825, WR05-1080, WR06-887, WR06-1238, WR07-1307, WR07-1816, WR07-1866, WR07-2188, and WR07-2368 were above 90 points, and the change difference of the taste detection scores in each period was within 5%; the change of the RVA spectrum retrogradation value of the instant rice in each period was within 5% of -0.24 / Pa.s, and the texture analysis hardness value was 1600g ± 65g. Especially, the taste scores after rehydration were all above 88 points. Compared with the taste value of fresh and wet instant rice, the score change was within 5%, the rehydration time was within 3.0 minutes, the rehydration rate was above 3.0%, the α-degree was above 96%, and the rice showed a soft, smooth, shiny, non-clumping and non-undercooked appearance, showing excellent anti-aging regeneration and rehydration performance.

[0043] Based on the problems of the old varieties of the three local soft rice resources of Haopi, Haomülü, and Haoerwanghanduo, such as tall plants, poor resistance, low yield, complex heredity, and instability of their hybrid offspring as hybrid breeding parents, they were not selected. At the same time, the endosperms of the three materials WR07-1307, WR07-1816, and WR07-1866 are semi-transparent, while the six materials WR05-825, WR05-1080, WR06-887, WR06-1238, WR07-2188, and WR07-2368 have the marked trait of grayish-white endosperm. Considering that the excellent traits of anti-aging regeneration and rehydration performance may be related or linked to the marked trait of grayish-white endosperm, which is beneficial to the separation and selection of hybrid offspring and genetic analysis, the six materials WR05-825, WR05-1080, WR06-887, WR06-1238, WR07-2188, and WR07-2368 with the marked trait of grayish-white endosperm were used as the selected rice germplasm resources varieties carrying the anti-aging regeneration trait gene a.

[0044] 2. Breeding of high-quality soft rice strain VIII with stable traits, good anti-aging regeneration and rehydration performance.

[0045] Hybridize the six selected materials carrying the anti-aging retrogradation trait gene a with fine rice varieties, and through the identification of allelic anti-aging retrogradation, genes for good rehydration performance traits, and combining ability, select soft rice lines with anti-aging retrogradation and good rehydration performance. The specific operations are as follows: In this example, 14 materials, namely Wenhui 206, Wenhui 247, Wenhui 184, Wenhui 163, Wenhui 221, Wenhui 242, Wenhui 264, Wenhui 324, Wenhui 305, Wenhui 499, Wenhui 791, Wenhui 821, Wenhui 1021, and Wenhonghui 628, which are high-quality scented soft rice restorer lines with the genetic background of Yunnan scented soft rice germplasm resources and transparent endosperm, are used as fine rice varieties.

[0046] In April 2013, at the base of Wenshan Academy of Agricultural Sciences in Sanya City, Hainan Province, the above-mentioned improved rice seeds were crossbred pairwise with 6 materials such as WR05-825, WR05-1080, WR06-887, WR06-1238, WR07-2188, and WR07-2368 to obtain WR05-825 / Wenhui 206, WR05-825 / Wenhui 247, WR05-825 / Wenhui 184, WR05-825 / Wenhui 163, WR05-825 / Wenhui 221, WR05-825 / Wenhui 242, WR05-825 / Wenhui 264, WR05-825 / Wenhui 324, WR05-825 / Wenhui 305, WR05-825 / Wenhui 499, WR05-825 / Wenhui 791, WR05-825 / Wenhui 821, WR05-825 / Wenhui 1021, WR05-825 / Wenhonghui 628, WR05-1080 / Wenhui 206, WR05-1080 / Wenhui 247, WR05-1080 / Wenhui 184, WR05-1080 / Wenhui 163, WR05-1080 / Wenhui 221, WR05-1080 / Wenhui 242, WR05-1080 / Wenhui 264, WR05-1080 / Wenhui 324, WR05-1080 / Wenhui 305, WR05-1080 / Wenhui 499, WR05-1080 / Wenhui 791, WR05-1080 / Wenhui 821, WR05-1080 / Wenhui 1021, WR05-1080 / Wenhonghui 628, WR06-887 / Wenhui 206, WR06-887 / Wenhui 247, WR06-887 / Wenhui 184, WR06-887 / Wenhui 163, WR06-887 / Wenhui 221, WR06-887 / Wenhui 242, WR06-887 / Wenhui 264, WR06-887 / Wenhui 324, WR06-887 / Wenhui 305, WR06-887 / Wenhui 499, WR06-887 / Wenhui 791, WR06-887 / Wenhui 821, WR06-887 / Wenhui 1021, WR06-887 / Wenhonghui 628, WR06-1238 / Wenhui 206, WR06-1238 / Wenhui 247, WR06-1238 / Wenhui 184, WR06-1238 / Wenhui 163, WR06-1238 / Wenhui 221, WR06-1238 / Wenhui 242, WR06-1238 / Wenhui 264, WR06-1238 / Wenhui 324, WR06-1238 / Wenhui 305, WR06-1238 / Wenhui 499, WR06-1238 / Wenhui 791, WR06-1238 / Wenhui 821, WR06-1238 / Wenhui 1021, WR06-1238 / Wenhonghui 628, WR07-2188 / Wenhui 206,84 test-cross hybrid combinations such as WR07-2188 / Wenhui 247, WR07-2188 / Wenhui 184, WR07-2188 / Wenhui 163, WR07-2188 / Wenhui 221, WR07-2188 / Wenhui 242, WR07-2188 / Wenhui 264, WR07-2188 / Wenhui 324, WR07-2188 / Wenhui 305, WR07-2188 / Wenhui 499, WR07-2188 / Wenhui 791, WR07-2188 / Wenhui 821, WR07-2188 / Wenhui 1021, WR07-2188 / Wenhonghui 628, WR07-2368 / Wenhui 206, WR07-2368 / Wenhui 247, WR07-2368 / Wenhui 184, WR07-2368 / Wenhui 163, WR07-2368 / Wenhui 221, WR07-2368 / Wenhui 242, WR07-2368 / Wenhui 264, WR07-2368 / Wenhui 324, WR07-2368 / Wenhui 305, WR07-2368 / Wenhui 499, WR07-2368 / Wenhui 791, WR07-2368 / Wenhui 821, WR07-2368 / Wenhui 1021, WR07-2368 / Wenhonghui 628 were then taken to the base of the Rice Research Institute of Wenshan Prefecture Academy of Agricultural Sciences in Wenshan City, Yunnan Province for sowing and planting.

[0047] The experiment was set up with three replicates, and the plot area was 13.5 m 2 , and 36 hills were transplanted in each plot, with single-plant transplantation in each hill, and sowing and transplantation were carried out simultaneously. In mid-September 2013, when the experimental materials matured, seed setting and yield measurement were carried out by investigation, and the hybrid F 1 The seeds of the combinations were taken to the hanging storage room of the Rice Research Institute of Wenshan Prefecture Academy of Agricultural Sciences in Yunnan Province for drying or sunning to dehydrate. When the seed moisture content dropped below 13%, for each hybrid F 1The seeds of the combined individual plants were shelled into brown rice for observation. The results showed that the grains with the trait of grayish-white endosperm identification were expressed in the seeds of all the tested and mated hybrid combinations, and the grains with the grayish-white endosperm marker trait accounted for about 1 / 3, indicating that the tested fragrant soft rice restorer line variety as a fine rice variety was allelic with the anti-aging and regrowth gene a carrying the grayish-white endosperm marker trait, and might be controlled by a single recessive gene. Among the 84 tested and mated hybrid combinations, the yields of 5 combinations, namely WR07-2368 / Wenhui 247, WR05-825 / Wenhui 206, WR07-2368 / Wenhui 247, WR05-825 / Wenhui 247, and WR07-2188 / Wenhui 247, were the highest, reaching 702.6 kg / mu, 694.7 kg / mu, 689.6 kg / mu, 674.4 kg / mu, and 669.5 kg / mu respectively. At the same time, the average yield of the combinations with WR07-2368 as the female parent was higher than that of the combinations with the other WR05-825, WR05-1080, WR06-887, WR06-1238, and WR07-2188 as the female parent, and the average yield of the combinations with Wenhui 247 as the male parent was also higher than that of the combinations prepared with the other 13 restorer lines, indicating that WR07-2368 and Wenhui 247 not only had the allelic anti-aging and regrowth gene a with the grayish-white endosperm marker trait, but also had the best combining ability. Using them as hybrid parents respectively, it was easy to successfully breed high-combining ability hybrid offspring varieties. Therefore, the material WR07-2368 was used as the donor soft rice variety of the recessive anti-aging and regrowth gene a, and Wenhui 247 was used as the fine rice variety with the allelic anti-aging and regrowth gene a to the donor variety.

[0048] In November 2013, WR07-2368 and Wenhui 247 were taken to the base of Wenshan Prefecture Academy of Agricultural Sciences in Sanya City, Hainan Province for planting. In March 2014, hybridization was carried out to integrate the high-quality recessive anti-aging and regrowth trait gene a and the excellent traits genes such as high yield, resistance, wide adaptability, and strong combining ability into one, and hybrid seeds with the recessive anti-aging and regrowth trait gene a and the excellent traits genes such as high yield, resistance, wide adaptability, and strong combining ability were obtained. In April of the same year, the hybrid seeds together with their hybrid parents were taken to the base of Wenshan Prefecture Academy of Agricultural Sciences in Wenshan City, Yunnan Province for sowing, transplanting, and planting, and self-crossed to promote the separation and recombination of the target trait gene a and other excellent trait genes such as combining ability, forming pure target trait gene phenotype seeds (aa). When transplanting, the hybrid F 1 combination was planted adjacent to its hybrid parents.

[0049] In early September 2014, the F 1The seeds of the hybrid parents were taken to the hanging room of the Rice Research Institute of Wenshan Academy of Agricultural Sciences in Wenshan City, Yunnan Province for drying and dehydration. When the moisture content of the seeds dropped to 13%, the F of the hybrid combination WR07-2368 / Wenhui 247 was 1 The grains of the single plant and its hybrid parents were shelled into brown rice for observation to identify the expression of the target trait and select the grains. The recessive gray-white endosperm anti-aging regeneration marker trait was used as the selection marker to select the seeds with the genotype homozygous (aa) anti-aging regeneration trait gene a (phenotype seeds VII of the present invention). Because, according to the genetic characteristics of the endosperm, the hybrid F 1 The rice grains of the combined single plant are already F 2 In the seeds of the first generation, the gene a controlling the anti-aging and regeneration trait and other excellent trait genes such as combining ability have been separated and recombined, and the homozygous anti-aging and regeneration phenotypic traits (aa) and other target genotypes have been formed, so as to obtain seeds with phenotypic traits such as anti-aging and regeneration, especially the seeds with recessive gray-white endosperm anti-aging and regeneration marker phenotypic traits controlled by recessive genes. Their offspring will not be separated and will always be seeds with gray-white endosperm anti-aging and regeneration marker phenotypic traits.

[0050] In early November 2014, seeds (aa) with the gray-white endosperm anti-aging and regeneration marker trait gene were brought to the base of Wenshan Academy of Agricultural Sciences in Sanya, Hainan Province for planting. The planting population was 1,200 plants and self-pollination was carried out. When mature in April 2015, 100 single main stem ears with good agronomic traits were selected and brought to the hanging storage room of Wenshan Academy of Agricultural Sciences in Yunnan Province for drying. After dehydration to a moisture content of less than 13.0%, the seeds were shelled into brown rice and observed. The endosperm of each single plant all had the gray-white endosperm anti-aging and regeneration marker trait. Afterwards, the gray-white endosperm anti-aging and regeneration marker trait was used as a selection marker for plant selection. The selected marker had a bright color and excellent high-yield traits. The single plants were shuttled in different ecological regions of Wenshan and Sanya, and self-pollinated, separated, multiplied and selected twice a year to continuously purify the comprehensive excellent trait genes of the selected single plants. By April 2020, the multiplied generations to F in Sanya were completed. 6 When the comprehensive target traits of the selected individual plants tended to be stable, 18 individual plants with compact plant type, high yield and good resistance were selected for strain comparison test, anti-aging and taste quality identification.

[0051] The strain comparison test was conducted at the Wenshan Academy of Agricultural Sciences Experimental Base in Wenshan City, Yunnan Province. The test was conducted without replication and the plot area was 13.3 m 2, arranged in a randomized block design. The high-yielding control variety Wendaoxiang 11, a conventional rice variety in Yunnan Province, was used as the control for yield performance. The hybrid parent WR07-2368 was used as the control for anti-aging regrowth and eating quality identification. The experiment was sown in May 2020. 200 individual plants were transplanted in each plot. When the experimental materials matured in September of the same year, economic traits such as the whole growth period, plant height, panicle length, effective panicles, spikelets per panicle, seed setting rate, 1000-grain weight, and yield, as well as traits such as stability and resistance, were investigated and evaluated for the tested individual plants. The results showed that there were 10 lines with stable comprehensive traits, strong resistance, and yields exceeding the control variety, 6 lines with yields close to the control variety, 2 lines with poor resistance, unstable traits, and low yields.

[0052] The rice of 16 lines with yields exceeding or close to the control variety, strong resistance, and stable traits were subjected to anti-aging regrowth and sensory eating quality identification. The identification results showed that the amylose content of 12 lines such as WR14-608, WR14-627, WR14-630, WR14-639, WR14-644, WR14-648, WR14-668, WR14-675, WR14-678, WR14-686, WR14-690, and WR14-712 was 10.0±0.8%, the gel consistency was more than 90 mm, and the alkali spreading value was more than 6.6; the eating quality value was more than 88 points, the sensory eating quality score was more than 90 points, the change difference in the eating quality detection score for each period was within 5%, the change in the RVA profile retrogradation value was within 5% of -0.24 / Pa.s, and the hardness value was also 1600±65 g. Especially after rehydration, the eating quality score was more than 88 points. Compared with the eating quality value of fresh and wet instant rice, the change range was within 5%, the rehydration time was within 3.0 minutes, the rehydration rate was more than 3.0%, the α-degree of gelatinization was more than 96%, and the cooked rice showed a soft, smooth, shiny appearance, without caking or uncooked grains. It showed excellent anti-aging regrowth and rehydration performance. The results of the eating quality meter, RVA profile retrogradation value, and texture hardness analysis were consistent with the sensory eating quality identification results. Especially the results of anti-aging regrowth and rehydration performance were consistent with those of the donor hybrid parent WR07-2368 with the recessive anti-aging regrowth marker trait gene a of grayish-white endosperm, which also confirmed that the recessive anti-aging regrowth marker trait of grayish-white endosperm is an excellent heritable trait. The anti-aging regrowth and rehydration performance of 3 lines such as WR14-636, WR14-670, and WR14-694 were also consistent with those of the donor hybrid parent WR07-2368 with the recessive anti-aging regrowth marker trait gene a of grayish-white endosperm. However, whether at room temperature or refrigerated, the gloss of the instant rice became dull after 30 days of cooling, affecting the product quality, so they were eliminated. The amylose content of line WR14-677 exceeded 12.6% and it was no longer retained.

[0053] So far, this example screened out 12 strains with recessive gray-white endosperm anti-aging and regeneration marker traits, including WR14-608, WR14-627, WR14-630, WR14-639, WR14-644, WR14-648, WR14-668, WR14-675, WR14-678, WR14-686, WR14-690, and WR14-712, as high-quality soft rice strains with stable traits, anti-aging and good rehydration performance.

[0054] 3. Select and breed high-quality soft rice varieties that have excellent anti-aging and regeneration properties, excellent rehydration performance, as well as excellent comprehensive agronomic traits such as high yield, adaptability and resistance.

[0055] Based on the selected high-quality soft rice strains with stable traits, good anti-aging and regeneration, and good rehydration performance, we will further select high-quality soft rice strains with excellent comprehensive agronomic traits such as anti-aging and regeneration, excellent rehydration performance, high yield, adaptability and resistance, as follows: In order to accurately identify the yield, adaptability, disease resistance and stability of 12 strains with recessive gray-white endosperm anti-aging and regeneration marker traits, including WR14-608, WR14-627, WR14-630, WR14-639, WR14-644, WR14-648, WR14-668, WR14-675, WR14-678, WR14-686, WR14-690, and WR14-712, selected in Example 2, especially the genetic characteristics and stability of the recessive gray-white endosperm anti-aging and regeneration marker traits, multi-point field advantage identification, recessive anti-aging and regeneration trait genetic characteristics and stability analysis were carried out.

[0056] In April 2021, 12 strains with recessive gray-white endosperm anti-aging regeneration marker traits were used as test materials to conduct multi-point superiority identification tests in 10 different ecological regions, including Wenshan, Jinghong, Mengzi, Luoping, Longyang, Mangshi, Tengchong in Yunnan, Guiyang in Guizhou, Guanghan in Sichuan, and Nanning in Guangxi Zhuang Autonomous Region. The test was not repeated, the area of ​​the plot was 0.02 mu, and 360 clumps were planted in each plot, with single planting. The pilots in Yunnan Province used the Yunnan Province high-quality conventional rice regional test control variety Wendao No. 11 as the control variety, and Sichuan, Guizhou, and Guangxi Zhuang Autonomous Region used the local high-quality conventional rice main varieties as the control. When mature, we conducted seed testing and yield measurement surveys based on plant type, tillering ability, uniformity, entire growth period, resistance to rice blast, effective ears per mu, plant height, number of grains per ear, fruit setting rate, 1000-grain weight and yield. We also selected seeds from pilot materials in Wenshan, Luoping, Guiyang and Nanning and dried them for anti-aging, regeneration and rehydration performance tests.

[0057] Based on the results of the variety testing and yield measurement surveys at each pilot site, the yields of all the tested materials were higher than that of the control. Among them, the yields of 10 lines, namely WR14-608, WR14-627, WR14-639, WR14-644, WR14-648, WR14-668, WR14-678, WR14-686, WR14-690, and WR14-712, were more than 5.0% higher than that of the control, reaching a significant level. The taste values and sensory taste scores of the instant rice made from the tested materials at the Wenshan, Luoping, Guiyang, and Nanning pilot sites were not only consistent but also above 90 points. Under normal temperature and refrigeration conditions, for the instant rice made from the same tested material planted in different ecological regions, the variation in taste test scores between different storage times of the instant rice for each tested material was within 5%, the change in the RVA profile retrogradation value was within 5% of -0.24 / Pa.s, and the hardness value was also 1600 ± 65 g. After rehydration, the taste scores were all above 88 points, and the difference in taste values from that of fresh and wet instant rice was within 5%. The rehydration time was within 3.0 minutes, the rehydration rate was above 3.0%, and the α-degree of gelatinization was above 96%. The test and identification results fully showed that the anti-aging and retrogradation resistance and rehydration performance of the tested materials were consistent with those of the hybrid parent WR07-2368, the donor of the anti-aging and retrogradation resistance marker trait gene a with grayish-white endosperm. The expression of the anti-aging and retrogradation resistance marker trait a of the grayish-white endosperm was not affected by the planting ecological environment and had stable heredity.

[0058] In November 2021, ten lines such as WR14-608, WR14-627, WR14-639, WR14-644, WR14-648, WR14-668, WR14-678, WR14-686, WR14-690, and WR14-712 with a yield 5.0% higher than the control and the scented soft rice sterile line Wenxiang 28A with transparent endosperm were taken to the experimental base of Wenshan Prefecture Academy of Agricultural Sciences in Sanya City, Hainan Province for staged planting. At the beginning of April 2022, Wenxiang 28A was used as the female parent to cross with ten lines such as WR14-608, WR14-627, WR14-639, WR14-644, WR14-648, WR14-668, WR14-678, WR14-686, WR14-690, and WR14-712, obtaining seeds of ten test cross combinations including Wenxiang 28A / WR14-608, Wenxiang 28A / WR14-627, Wenxiang 28A / WR14-639, Wenxiang 28A / WR14-644, Wenxiang 28A / WR14-648, Wenxiang 28A / WR14-668, Wenxiang 28A / WR14-678, Wenxiang 28A / WR14-686, Wenxiang 28A / WR14-690, and Wenxiang 28A / WR14-712. After maturity, these seeds were harvested and taken to the experimental base of Wenshan Prefecture Academy of Agricultural Sciences in Wenshan City, Yunnan Province for planting. After maturity at the beginning of September 2022, the seeds of the test cross combinations were harvested separately for air-drying, dehydration, shelling, and observation. The results showed that all the seeds of the test cross combinations expressed the recessive grayish-white endosperm anti-aging and retrogradation marker traits. The trait of non-marked transparent endosperm was dominant over the trait of grayish-white endosperm with anti-aging and retrogradation, and the trait segregation ratio conforms to 3:1. The test results proved that the grayish-white endosperm anti-aging and retrogradation marker trait is controlled by a single recessive gene, and also revealed that the correlation or linkage between the recessive grayish-white endosperm trait and the traits of anti-aging and retrogradation and excellent rehydration performance is not affected by the planting ecological environment. This is conducive to accurately selecting varieties with anti-aging and retrogradation and excellent rehydration performance through marker selection, and improving the breeding efficiency of special-purpose rice for high-quality instant rice processing.

[0059] Thus, ten WR14-608, WR14-627, WR14-639, WR14-644, WR14-648, WR14-668, WR14-678, WR14-686, WR14-690, and WR14-712 with the recessive grayish-white endosperm anti-aging and retrogradation marker traits, high yield, good high-yield traits, strong resistance, and wide adaptability are used as high-quality soft rice lines of the present invention with excellent anti-aging and retrogradation, rehydration performance, and comprehensive agronomic traits such as high yield, adaptability, and resistance.

[0060] 4. Screening of special-purpose rice for high-quality instant rice processing with high yield, high resistance, wide adaptability, and strong combining ability.

[0061] Using 10 selected high-quality soft rice lines as experimental materials, breed high-quality soft rice varieties with high yield, high resistance, wide adaptability, and strong combining ability, which have anti-aging and rehydration properties. Specifically as follows: In early April 2023, in order to accurately evaluate the yield increase potential of the successfully bred high-quality soft rice line IX with excellent anti-aging and rehydration properties, high yield, adaptability, and resistance, a high-quality soft rice variety with anti-aging and rehydration properties, high yield, high resistance, wide adaptability, and strong combining ability was selected. Using the above 10 high-quality soft rice lines as test materials and the conventional high-quality rice variety Wendao 11, which was the control variety in the Yunnan regional trial at that time, as the control, a variety comparison test and demonstration were carried out. The variety comparison test was set up at the experimental base of the Wenshan Prefecture Academy of Agricultural Sciences in Yunnan Province. Each plot had an area of 0.02 mu, with 400 hills planted in each plot, single-plant planting, and three replicates. When the experimental materials matured in September 2023, seedling examination and investigation were carried out according to the effective panicles per mu, plant height, panicle length, number of grains per panicle, number of filled grains per panicle, seed setting rate, 1000-grain weight, single-plant weight, plot weight, etc. The test results showed that the yield of each line was higher than that of the control Wendao 11. There were 8 lines with a yield increase of more than 5.0%, namely WR14-608, WR14-627, WR14-644, WR14-648, WR14-668, WR14-678, WR14-686, and WR14-690. The top three lines in terms of yield were WR14-686, WR14-690, and WR14-644, with yields of 624.9 kg / mu, 612.2 kg / mu, and 606.7 kg / mu respectively, and the yield increase rates were 9.9%, 7.7%, and 6.7% respectively. They also had the best high-yield traits, a moderate maturity period, and the strongest resistance.

[0062] High-yield cultivation technology demonstration sites were set up in different altitude ecological rice areas such as Wenshan, Yanshan, Funing in Wenshan Prefecture and Mangshi in Dehong Prefecture. Using the fragrant soft rice variety Wendao 11, which was widely promoted in Yunnan Province at that time, as the control, 1.0 mu of each line was planted at each demonstration site, and cultivation management was carried out according to the local rice planting management level of each demonstration site. The results showed that there were 4 lines with an average yield per mu higher than the control by more than 5.0% at each demonstration site, namely WR14-686, WR14-690, WR14-644, and WR14-668, with yields of 602.8 kg / mu, 594.2 kg / mu, 590.0 kg / mu, and 586.7 kg / mu respectively. Line WR14-686 had the highest yield at each demonstration site, was highly resistant to rice blast, had good color change after maturity, and had the best high-yield traits.

[0063] Meanwhile, in order to accurately identify the combining ability of the successfully selected high-quality soft rice lines with excellent comprehensive agronomic traits such as anti-aging retrogradation resistance, excellent rehydration performance, high yield, adaptability, and resistance, and to select the line with the strongest combining ability from them, in July 2023, at the experimental base of Wenshan Prefecture Academy of Agricultural Sciences in Wenshan City, Yunnan Province, the three-line sterile lines of fragrant soft rice with good transparency, Haoxiang 24A, Wenxiang 28A, Zhuangxiang 2051A, and the two-line sterile lines Y58S, Long 638S, Jing 4155S were used as female parents, and the 10 lines such as WR14-608, WR14-627, WR14-639, WR14-644, WR14-648, WR14-668, WR14-678, WR14-686, WR14-690, WR14-712 with recessive grayish-white endosperm anti-aging retrogradation trait markers selected in Example 3 were used as male parents for pairwise hybridization to obtain 66 test cross combination seeds.

[0064] In April 2024, the advantage identification of test cross combinations was carried out at the experimental base of Wenshan Prefecture Academy of Agricultural Sciences in Wenshan City, Yunnan Province. The experiment was set with three replicates, the plot area was 0.02 mu, 360 hills were planted in each plot, and single-plant planting was used. The high-quality hybrid rice regional test control variety Lingheyou 78 in Yunnan Province was used as the control variety. By mid-September 2024, when the test cross combinations were mature, the seed setting rate, 1000-grain weight, single-plant weight, plot yield, etc. were investigated according to the effective panicles per mu, plant height, panicle length, number of grains per panicle, number of filled grains per panicle, seed setting rate, 1000-grain weight, single-plant weight, plot yield, etc. The test results showed that the yields of 9 test cross combinations such as Wenxiang 28A / WR14-686, Jing 4155S / WR14-686, Haoxiang 24A / WR14-686, Zhuangxiang 2051A / WR14-686, Y58S / WR14-644, Wenxiang 28A / WR14-644, Haoxiang 24A / WR14-644, Jing 4155S / WR14-668, Jing 4155S / WR14-690 increased by more than 5.0% compared with the control. Among them, the yield of the Wenxiang 28A / WR14-686 combination was the highest, reaching 722.5 kg / mu, and the average yield of the test cross combinations of WR14-686 and 6 sterile lines was higher than that of other sterile lines. The test results showed that the line WR14-686 not only had the highest yield as a conventional rice, but also, when used as the male parent for test crosses with multiple sterile lines, the yields of most of its test cross combinations were higher than the control, and its combining ability was the strongest, and it had good application prospects as a restorer line.

[0065] Since the strain WR14-686 showed the advantages of the highest yield, the strongest combining ability, strong resistance, and good high-yielding characteristics in the anti-aging regeneration, rehydration performance identification, as well as in the yield potential and test cross combination superiority identification test. Especially, the recessive grayish-white endosperm anti-aging regeneration marker trait has stable heredity. Therefore, WR14-686 is tentatively named Wenbaihui 686, which is the high-quality soft rice variety of the present invention with excellent anti-aging regeneration, rehydration performance, high yield, high resistance, wide adaptability, and strong combining ability.

[0066] In summary, the present invention successfully introduced the anti-aging regeneration gene discovered independently into improved varieties, and bred a special-purpose rice variety for high-quality instant rice processing with strong anti-aging regeneration, good rehydration performance, high yield, strong resistance, and wide adaptability.

[0067] It should be noted that the present invention is not limited to the above embodiments. The above embodiments are only examples, and the embodiments with the same structure and the same effect as the technical idea within the technical solution scope of the present invention are included in the technical scope of the present invention. In addition, within the scope not departing from the gist of the present invention, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways constructed by combining some constituent elements of the embodiments are also included in the scope of the present invention.

Claims

1. A breeding method for anti-aging and retrograde high-quality instant rice processing rice, characterized in that: The following steps are involved: The rice germplasm resource variety II with the anti-aging and regeneration trait gene a of gray-white endosperm was hybridized with the rice improved variety III, and the donor variety IV and the recipient variety V with the recessive gray-white endosperm anti-aging and regeneration trait gene a of the same allele were screened out through the determination of the allelism and combining ability of the anti-aging and regeneration trait gene a; Crossing donor variety IV with recipient variety V to obtain hybrid seed VI, and selfing the hybrid seed VI to obtain homozygous phenotypic seed VII having the gene a for the gray-white endosperm anti-aging regeneration trait; Planting seeds VII, using the gray-white endosperm anti-aging regeneration marker trait as a selection marker, and conducting multi-generation self-pollination selection to obtain soft rice line VIII; The soft rice line IX was selected from the soft rice line VIII based on agronomic traits and used as a special rice for instant rice processing.

2. The breeding method according to claim 1, characterized in that The following steps are also included: After field productivity and combining ability identification tests, the soft rice line IX was further screened and applied as a special rice for instant rice processing.

3. The breeding method according to claim 1, characterized in that The rice germplasm resource variety II is obtained by the following method: collecting soft rice germplasm resources and its derivative variety I, and obtaining them through anti-aging regeneration and rehydration performance identification.

4. The breeding method according to claim 1, characterized in that The rice germplasm resource variety II is selected from one or more of Haopi, Haomurv, Haoerwanghanduo, WR05-825, WR05-1080, WR06-887, WR06-1238, WR07-2188, and WR07-2368.

5. The breeding method according to claim 4, characterized in that The donor variety IV is WR07-2368.

6. The breeding method according to claim 1 or 4, characterized in that: The rice variety III is a restorer line material with a Yunnan fragrant soft rice germplasm resource genetic background and transparent endosperm.

7. The breeding method according to claim 6, characterized in that The rice variety III is selected from Wenhui 206, Wenhui 247, Wenhui 184, Wenhui 163, Wenhui 221, Wenhui 242, Wenhui 264, Wenhui 324, Wenhui 305, Wenhui 499, Wenhui 791, Wenhui 821, Wenhui 1021, and Wenhonghui 628.

8. The breeding method according to claim 4, characterized in that The receptor variety V is Wenhui 247.

9. The breeding method according to claim 1, characterized in that: The number of generations of the multi-generation self-pollination is 6-8 generations.

10. Application of the breeding method according to any one of claims 1 to 9 in breeding of high-quality rice.

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