A method for breeding hybrid high-resistant starch rice

Abstract

The present invention discloses a breeding method for hybrid high-resistant starch rice. Yitangjing No. 1 is used as the male parent and recurrent parent, and is hybridized and backcrossed m times with the sterile line Anjing 1A of the target three-line hybrid rice Anjingyou No. 1; and after multiple backcrosses with the male parent Yitangjing No. 1, the sterile line A'6 is cultivated; then the restorer line Yudao No. 1 of the target three-line hybrid rice Anjingyou No. 1 is used as the male parent and recurrent parent, and is hybridized and backcrossed n times with Yitangxian No. 1; and then, through continuous test crossing with the sterile line, a high-yield, high-quality and disease-resistant hybrid combination and the corresponding restorer line are obtained; finally, a seed breeding and production system of the sterile line A'6, the restorer line R'6 and the new high-resistant starch hybrid rice variety prepared therefrom is constructed to breed hybrid high-resistant starch rice. The hybrid high-resistant starch rice cultivated by the method of the present invention is suitable for simplified cultivation while maintaining its function, and is high-yielding and high-efficient, thus empowering a healthy China and common prosperity.

Description

Technical Field

[0001] The invention belongs to the technical field of rice breeding, and particularly relates to a breeding method for hybrid high-resistant starch rice. Background Art

[0002] According to estimates from the Healthy China Action, the prevalence of diabetes in my country is 12.8%, affecting 150 million people. The prevalence of dyslipidemia is 18.6%, affecting 160 million people. Resistant starch (RS) is a general term for starch and its degradation products that are difficult to digest and absorb in the small intestine of healthy people. It has many important physiological functions, including lowering blood sugar and lipids, controlling weight, and promoting intestinal health.

[0003] Domestic research institutions such as Zhejiang University, the Institute of Genetics and Developmental Biology of the Chinese Academy of Sciences, and Zhejiang Green Giant Biotechnology Co., Ltd. have conducted research on resistant starch rice. They have developed conventional high-resistant starch rice lines such as Zhefu 111, Yitangxian 1, and Yitangjing 1, as well as high-resistant starch indica hybrid rice lines such as Zheda Liangyou Yitangxian 1. However, these varieties still face challenges such as low taste and yield. Combining high-resistant starch rice with indica-japonica hybrid rice can further enhance its nutritional value and achieve high yield and efficiency.

[0004] Therefore, it is of great significance to breed a hybrid high-resistant starch rice that maintains its functions while being high-yielding and resistant to lodging, suitable for light and simplified cultivation, and high-yielding and efficient. Summary of the Invention

[0005] The object of the present invention is to provide a breeding method for hybrid high-resistant starch rice.

[0006] A method for breeding hybrid high-resistant starch rice, characterized by comprising the following steps:

[0007] 1) Breeding sterile lines:

[0008] (1-1) Yitangjing 1 was used as the male parent and backcross parent, and hybridized with the sterile line Anjing 1A of the target three-line hybrid rice Anjingyou 1 and backcrossed m times to obtain BC m F1 generation seeds;

[0009] (1-2) Planting BC m In the F1 generation, sterile plants were selected and then backcrossed with Yitangjing No. 1 to obtain BC m+1 F1 generation seeds;

[0010] (1-3) Planting BC m+1 In the F1 generation, sterile plants were determined, and the sterile line A'1 with high grain resistant starch was selected; it was backcrossed with the male parent Yitangjing No. 1 to obtain the sterile line A'2 seeds;

[0011] (1-4) Planting the sterile line A'2 and using the sterile line Anjing 1A as a control to identify the sterility of the sterile line A'2, and finally selecting the sterile line A'3 with complete sterility and backcrossing it with the male parent Yitangjing 1 to obtain the seeds of the sterile line A'4;

[0012] (1-5) Plant the sterile line A'4, select the sterile line A'5 whose sterility meets the characteristics of the sterile line, and backcross it with the male parent Yitangjing No. 1 to obtain the seeds of the sterile line A'6;

[0013] 2) Breeding of restorer lines:

[0014] (2-1) The target three-line hybrid rice Anjingyou 1 restorer line Yudao 1 was used as the male parent and backcross parent, and hybridized with Yitangxian 1 and backcrossed n times to obtain BC n F'1 generation seeds;

[0015] (2-2) Planting BC n F'1 generation, after self-pollination, harvest BC n F'2 generation seeds;

[0016] (2-3) Planting BC n In the F'2 generation, the restorer line R'1 with high resistant starch was selected and paired with the sterile line A'1 for test cross to obtain the restorer line R'2 seeds;

[0017] (2-4) Planting restorer line R'2, using restorer line Yudao No. 1 and target three-line hybrid rice Anjing You No. 1 as controls, observing hybrid combination A'2×R'2, selecting superior hybrid combination with high resistant starch and corresponding restorer line R'3, and test-crossing them with sterile line A'3 to obtain restorer line R'4 seeds;

[0018] (2-5) Planting restorer line R'4, identifying the yield, physical and chemical quality, and disease resistance of the superior hybrid combination A'4×R'4, selecting the high-yield, high-quality, and disease-resistant hybrid combination and the corresponding restorer line R'5, and obtaining seeds of restorer line R'6;

[0019] 3) Establish a seed propagation and production system for the sterile line A'6, the restorer line R'6 and their formulated new high-resistant starch hybrid rice varieties, and ultimately breed hybrid high-resistant starch rice.

[0020] Among them, Yitangjing No. 1 is a new variety of high-resistant starch indica rice bred by Zhejiang Green Giant Biotechnology Co., Ltd., and has applied for and been authorized for a new plant variety right from the Ministry of Agriculture and Rural Affairs (variety right number: CNA20140191.9).

[0021] Yitangxian No. 1 is a new japonica rice variety with high starch resistance selected and bred by Zhejiang Green Giant Biotechnology Co., Ltd., which has applied for and been authorized for new plant variety rights from the Ministry of Agriculture and Rural Affairs (variety right number: CNA20140190.0).

[0022] The target three-line hybrid rice is Anjing You 1, whose parental male sterile line A is Anjing 1A and the restorer line R is Yudao 1. Anjing You 1 is a new three-line hybrid rice variety (Zheshendao 2018021) developed by Zhejiang University, the China National Rice Research Institute, and the Institute of Genetics and Developmental Biology of the Chinese Academy of Sciences, using the male sterile line Anjing 1A and the restorer line Yudao 1.

[0023] In the step (1-1), m≤3; in the step (2-1), n≤3.

[0024] The criterion for judging whether the resistant starch content is high is that the resistant starch content is ≥8.0%.

[0025] In step (1-4), the sterility evaluation criteria are: pollen sterility rate ≥ 99.99% and bagging fruit setting rate ≤ 0.01%.

[0026] In step (2-5), the criteria for judging high yield, high quality and disease resistance are: rice yield ≥ 650 kg / mu, physical and chemical index gel consistency ≥ 70 mm, and rice blast and leaf blight susceptibility being moderate or below.

[0027] Beneficial effects of the present invention:

[0028] (1) The present invention uses resistant starch and target indica-japonica hybrid rice varieties as a basis to breed new indica-japonica intermediate hybrid rice varieties with high resistant starch, so as to better play the functions of functional nutrition and high yield and high efficiency.

[0029] (2) The present invention uses two resistant starch alleles but with indica and japonica genetic backgrounds as parents, and separately improves the sterile line and the restorer line, which can avoid the common homogenization problem in rice breeding and lay a genetic foundation for the high-yield and high-quality hybrid advantage of resistant starch hybrid rice. DETAILED DESCRIPTION

[0030] To facilitate understanding of the present invention, the present invention will be described more fully below. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0031] Example 1 Genetic Analysis of Fertility in Hybrid Offspring of Yitangjing No. 1 and Anjing 1A

[0032] Paired hybridization of Yitangjing 1, a new high-resistant starch variety selected earlier, with Anjing 1A revealed that Yitangjing 1 had a high resistant starch content, fertile pollen, and normal bagged seed set. Anjing 1A had a very low resistant starch content, completely sterile pollen, and a bagged seed set rate of 0, making it a typical sterile line. Anjing 1A × Yitangjing 1 exhibited the same sterility as Anjing 1A, with completely sterile pollen and a bagged seed set rate of 0, but significantly higher resistant starch content (Table 1). This provides the prerequisite for the direct breeding of resistant starch sterile lines through backcrossing.

[0033] Table 1 Genetic analysis of fertility in hybrid offspring of Yitangjing 1 and Anjing 1A

[0034] Hybrid F1 characteristic traits Resistant starch content Group Sports pollen fertility Bagging rate Yitangjing No. 1 10.2％ Fully fertile Fertile, 99.99% 95.6％ Anjing 1A 0.2％ infertility Infertility, 99.99% 0％ Anjing 1A×Yitangjing No. 1 2.3％ infertility Infertility, 99.99% 0％

[0035] Example 2 Genetic Analysis of Resistant Starch in Yitangjing No. 1 and Yitangxian No. 1

[0036] Observation and identification of reciprocal hybrid combinations of Yitangjing 1 and Yitangxian 1 showed that the resistant starch content of the hybrids was high, indicating that the resistant starch content of Yitangjing 1 and Yitangxian 1 is allelic (Table 2). This provides a technical basis for the targeted selection and improvement of sterile and restorer lines. In addition, the use of two genetically different resistant starch donors, indica and japonica types of Yitangjing 1 or Yitangxian 1, for improvement can avoid the homogenization commonly seen in breeding and lay the genetic foundation for the heterosis of high yield and high quality in resistant starch hybrid rice.

[0037] Table 2 Genetic analysis of resistant starch in Yitangjing 1 and Yitangxian 1

[0038]

[0039] Example 3 Breeding Method for Hybrid High-Resistant Starch Rice Based on Yitangjing No. 1, Yitangxian No. 1 and Anjingyou No. 1 (CMS Line Anjing 1A, Yudao No. 1)

[0040] Yitangjing No. 1 is a new indica rice variety with high resistant starch, bred by Zhejiang Green Giant Biotechnology Co., Ltd. The company has applied for and received new plant variety rights from the Ministry of Agriculture and Rural Affairs (Variety Rights No.: CNA20140191.9). This variety boasts a plant height of 87 cm, 10.2% resistant starch, 25.5% amylose, a gel consistency of 46 mm, a taste score of 55, and a yield of 400 kg / mu. It is available from Zhejiang Green Giant Biotechnology Co., Ltd.

[0041] Yitangxian No. 1 is a new japonica rice variety with high resistant starch, bred by Zhejiang Green Giant Biotechnology Co., Ltd. The company has applied for and received new plant variety rights from the Ministry of Agriculture and Rural Affairs (Variety Rights No.: CNA20140190.0). This variety boasts a plant height of 95 cm, 10.7% resistant starch, 29.6% amylose, a gel consistency of 39 mm, a flavor score of 50, and a yield of 450 kg / mu. It is available from Zhejiang Green Giant Biotechnology Co., Ltd.

[0042] Anjing You 1 is a new three-line hybrid rice variety (Zheshendao 2018021) developed by Zhejiang University, the China National Rice Research Institute, and the Institute of Genetics and Developmental Biology of the Chinese Academy of Sciences, using the sterile line Anjing 1A and the restorer line Yudao 1. This variety has a plant height of 163 cm, 0.3% resistant starch, 14.9% amylose, a gel consistency of 68 mm, a taste score of 85, and a yield of 650 kg / mu. It is available from Zhejiang University.

[0043] The breeding method of hybrid high-resistant starch rice has the following specific steps:

[0044] 1) Breeding of high-resistant starch sterile lines:

[0045] (1-1) Using Yitangjing No. 1 as the male parent and recurrent parent, it was hybridized with the sterile line Anjing 1A of the target three-line hybrid rice Anjingyou No. 1 and backcrossed twice to obtain BC2F1 generation seeds; using Yudao No. 1, the restorer line of the target three-line hybrid rice Anjingyou No. 1, as the male parent and recurrent parent, it was hybridized with Yitangxian No. 1 and backcrossed twice to obtain BC2F'1 generation seeds;

[0046] (1-2) Planting the BC2F1 generation, selecting 21 sterile plants, and backcrossing them with Yitangjing No. 1 to obtain BC3F1 generation seeds;

[0047] (1-3) Planting the BC3F1 generation, determining the sterile plants, and selecting 9 sterile lines A'1 with grain resistant starch ≥8.0%; backcrossing with the male parent Yitangjing No. 1 to obtain 9 sterile line A'2 seeds;

[0048] (1-4) Planting the sterile line A'2 and using the sterile line Anjing 1A as a control to identify the sterility of the sterile line A'2, and finally selecting three sterile lines A'3 with a pollen sterility rate ≥99.99% and a bagging fruit set rate ≤0.01%. They were backcrossed with the male parent Yitangjing 1 to obtain three seeds of the sterile line A'4;

[0049] (1-5) Plant the sterile line A'4, select the sterile line A'5 whose sterility meets the characteristics of the sterile line, and backcross it with the male parent Yitangjing No. 1 to obtain one seed of the sterile line A'6;

[0050] 2) Breeding of restorer lines:

[0051] (2-1) The target three-line hybrid rice Anjingyou 1 restorer line Yudao 1 was used as the male parent and backcross parent, and was hybridized and backcrossed twice with Yitangxian 1 to obtain BC2. n F'1 generation seeds;

[0052] (2-2) Planting BC2F'1 generation, self-pollinating, and harvesting BC2F'2 generation seeds;

[0053] (2-3) Planting the BC2F'2 generation, selecting 35 restorer lines R'1 with grain resistant starch ≥8.0%, and test-crossing them with the sterile line A'1 to obtain 26 restorer line R'2 seeds;

[0054] (2-4) Planting restorer line R'2, using restorer line Yudao No. 1 and target three-line hybrid rice Anjing You No. 1 as controls, observing hybrid combinations A'2×R'2, selecting 8 excellent hybrid combinations with resistant starch ≥ 8.0% and 8 corresponding restorer lines R'3, and testcrossing them with sterile line A'3 to obtain restorer line R'4 seeds;

[0055] (2-5) Planting restorer line R'4, identifying the yield, physical and chemical quality, and disease resistance of the superior hybrid combination A'4×R'4, selecting three hybrid combinations with rice yield ≥650 kg / mu, physical and chemical index gel consistency ≥70 mm, and moderate or lower susceptibility to rice blast and leaf blight, and three corresponding restorer lines R'5, to obtain seeds of restorer line R'6;

[0056] 3) Construction of the sterile line Anjing 1A' +抗性淀粉 (i.e. A'6), Yudao No. 1' +抗性淀粉 (i.e. R'6) and its seed breeding and production system for new hybrid rice varieties with formulated resistant starch, and finally bred one hybrid rice with high resistant starch, tentatively named "Green Man Hybrid Anti-powder No. 1".

[0057] The comparison of the indica and japonica rice types, growth period, resistant starch content, plant height, main stem thickness, rice yield, rice quality, amylose content, gel consistency and taste score of each variety is shown in Table 3.

[0058] Table 3 Comparison of index traits of Yitangjing No. 1, Yitangxian No. 1, Anjingyou No. 1 and Lurenzakangfen No. 1

[0059]

[0060]

[0061] Note: *The difference between Greenman Zakangfen No. 1 and its parents and target hybrid combination is extremely significant at the 0.05 level.

[0062] The measurement methods for each indicator in Table 2 are as follows: plant height, stem thickness, lodging resistance, and rice yield: National Rice Variety Test Observation Recording Items, Methods, and Standards (Trial); resistant starch: AOAC 991.43; rice quality, amylose content, gel consistency, and taste score: NY / T 593-2013.

[0063] After joint evaluation and identification, the hybrid high-resistant starch rice "Green Man Hybrid Anti-powder No. 1" was bred, with a resistant starch content of 10.5%, a plant height of 122cm, a rice yield of 670kg / mu, an amylose content of 25.6%, a gel consistency of 73mm, and a taste score of 78.

[0064] Compared to its two resistant starch parents and the target hybrid rice variety, "Green Man Za Kang Fen No. 1" combines the advantages of both parents, but due to the addition of the resistant starch donor "Yitangxian No. 1" indica rice to the restorer line, it exhibits an intermediate type between indica and japonica. The increased genetic distance is significantly reflected in a thicker main stem (1.36 cm) and a significant increase in rice yield. Simultaneously, plant height is significantly reduced and lodging resistance is significantly enhanced, exceeding the expected breeding goals. Furthermore, while the amylose content of "Green Man Za Kang Fen No. 1" is still relatively high, the combination of indica and japonica is more suitable for different consumer tastes. This is highlighted by significantly better gel consistency and taste scores than both parents and the target hybrid combination (which has too low amylose content and is too sticky). Its edible properties exceed breeding expectations, greatly contributing to improved quality and efficiency, and a healthy and delicious lifestyle.

[0065] Therefore, the "Green Man Hybrid Anti-powder No. 1" bred by the present invention has the advantages of promoting a healthy and delicious life for the public, is resistant to lodging, is suitable for light and simplified cultivation, and saves labor and costs.

[0066] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. A method for breeding hybrid high-resistant starch rice, characterized in that: The following steps are involved: 1) Breeding sterile lines: (1-1) Yitangjing 1 was used as the male parent and backcross parent, and hybridized with the sterile line Anjing 1A of the target three-line hybrid rice Anjingyou 1 and backcrossed m times to obtain BC m F1 generation seeds; (1-2) Planting BC m In the F1 generation, sterile plants were selected and then backcrossed with Yitangjing No. 1 to obtain BC m+1 F1 generation seeds; (1-3) Planting BC m+1 In the F1 generation, sterile plants were determined, and the sterile line A'1 with high grain resistant starch was selected; it was backcrossed with the male parent Yitangjing No. 1 to obtain the sterile line A'2 seeds; (1-4) Planting the sterile line A'2 and using the sterile line Anjing 1A as a control to identify the sterility of the sterile line A'2, and finally selecting the sterile line A'3 with complete sterility and backcrossing it with the male parent Yitangjing 1 to obtain the seeds of the sterile line A'4; (1-5) Plant the sterile line A'4, select the sterile line A'5 whose sterility meets the characteristics of the sterile line, and backcross it with the male parent Yitangjing No. 1 to obtain the seeds of the sterile line A'6; 2) Breeding of restorer lines: (2-1) The target three-line hybrid rice Anjingyou 1 restorer line Yudao 1 was used as the male parent and backcross parent, and hybridized with Yitangxian 1 and backcrossed n times to obtain BC n F'1 generation seeds; (2-2) Planting BC n F'1 generation, after self-pollination, harvest BC n F'2 generation seeds; (2-3) Planting BC n In the F'2 generation, the restorer line R'1 with high resistant starch was selected and paired with the sterile line A'1 for test cross to obtain the restorer line R'2 seeds; (2-4) Planting restorer line R'2, using restorer line Yudao No. 1 and target three-line hybrid rice Anjing You No. 1 as controls, observing hybrid combination A'2×R'2, selecting superior hybrid combination with high resistant starch and corresponding restorer line R'3, and test-crossing them with sterile line A'3 to obtain restorer line R'4 seeds; (2-5) Planting restorer line R'4, identifying the yield, physical and chemical quality, and disease resistance of the superior hybrid combination A'4×R'4, selecting the high-yield, high-quality, and disease-resistant hybrid combination and the corresponding restorer line R'5, and obtaining seeds of restorer line R'6; 3) Establish a seed propagation and production system for the sterile line A'6, the restorer line R'6 and their formulated new high-resistant starch hybrid rice varieties, and ultimately breed hybrid high-resistant starch rice.

2. The method for breeding hybrid high-resistant starch rice according to claim 1, characterized in that: In the step (1-1), m≤3; in the step (2-1), n≤3.

3. The method for breeding hybrid high-resistant starch rice according to claim 1, characterized in that: The criterion for judging whether the resistant starch content is high is that the resistant starch content is ≥8.0%.

4. The method for breeding hybrid high-resistant starch rice according to claim 1, characterized in that: In step (1-4), the sterility evaluation criteria are: pollen sterility rate ≥ 99.99% and bagging fruit setting rate ≤ 0.01%.

5. The method for breeding hybrid high-resistant starch rice according to claim 1, characterized in that: In step (2-5), the criteria for judging high yield, high quality and disease resistance are: rice yield ≥ 650 kg / mu, physical and chemical index gel consistency ≥ 70 mm, and rice blast and leaf blight susceptibility being moderate or below.

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