阅读说明：本技术 一种低镉含量稻米杂交品种的选育方法 (Breeding method of rice hybrid variety with low cadmium content ) 是由 蒋开锋 杨莉 秦俭 张涛 杨乾华 游书梅 曹应江 郑家奎 钟英 李庚觅 于 2020-08-10 设计创作，主要内容包括：本发明公开了一种低镉含量稻米杂交品种的选育方法。该方法包括以下步骤：(1)将母本与父本杂交,获得杂交后代F1,然后于中度至重度镉污染环境中培育得到后代F2,并使其自交至少4代,筛选得到低镉含量的保持系B；(2)以不育系为母本,保持系B为父本进行杂交,获得杂交后代F1,然后用F1与父本保持系B连续回交6～10代,筛选获得不育系A；(3)然后以低镉含量恢复系R为父本,不育系A为母本进行杂交,筛选得到低镉含量的杂交品种。本申请结合传统的三系杂种优势利用技术,创制出稻米镉低积累的保持系、不育系、恢复系,培育的杂交稻品种综合了稻米镉低积累和高产优质等特性。(The invention discloses a breeding method of a rice hybrid variety with low cadmium content. The method comprises the following steps: (1) hybridizing the female parent and the male parent to obtain a filial generation F1, then culturing in a moderate-to-severe cadmium-polluted environment to obtain a progeny F2, selfing for at least 4 generations, and screening to obtain a maintainer line B with low cadmium content; (2) hybridizing the sterile line as a female parent and the maintainer line B as a male parent to obtain a hybrid progeny F1, then continuously backcrossing the hybrid progeny F1 and the male parent maintainer line B for 6-10 generations, and screening to obtain a sterile line A; (3) then, the low cadmium content restorer line R is used as a male parent, the sterile line A is used as a female parent for hybridization, and a hybrid variety with low cadmium content is obtained by screening. The application combines the traditional three-line heterosis utilization technology to create a maintainer line, a sterile line and a restorer line of low cadmium accumulation of rice, and the cultivated hybrid rice variety integrates the characteristics of low cadmium accumulation, high yield, high quality and the like of rice.)

1. A breeding method of a rice hybrid variety with low cadmium content is characterized by comprising the following steps:

(1) hybridizing the female parent and the male parent to obtain a filial generation F1, then culturing in a moderate-to-severe cadmium-polluted environment to obtain a progeny F2, selfing for at least 4 generations, and screening to obtain a maintainer line B with the cadmium content of less than 0.2 mg/kg;

at least one of the female parent and the male parent is a parent with cadmium content less than 0.2 mg/kg;

(2) hybridizing the sterile line as a female parent and the maintainer line B as a male parent to obtain a hybrid progeny F1, then continuously backcrossing the F1 and the male parent maintainer line B for 6-10 generations, and screening to obtain a sterile line A;

(3) then taking a restoring line R with the cadmium content of less than 0.2mg/kg as a male parent and a sterile line A as a female parent for hybridization, and screening to obtain a hybrid variety with low cadmium content.

2. The breeding method of the rice hybrid variety with low cadmium content according to claim 1, wherein the cadmium content in the soil in the moderate to severe cadmium-polluted environment is 0.8-1.1 mg/kg.

3. The method for breeding the rice hybrid variety with low cadmium content according to claim 1, wherein the hybridization in the step (1) is an amphiphilic parent hybridization, and the female parent of the hybridization is K42B with low cadmium content; the male parent is K17B variant line.

4. The method for breeding the rice hybrid variety with low cadmium content according to claim 1, wherein the hybridization in the step (1) is multi-parent compound hybridization, at least one of the hybridization parents is a parent with low cadmium content, and at least one of the hybridization parents is a maintainer line parent; the parent is a female parent or a male parent.

5. The method for breeding the hybrid rice variety with low cadmium content according to claim 1, wherein the sterile line is indica rice sterile line K17A.

6. The method for breeding the rice hybrid variety with low cadmium content according to claim 1, wherein the restorer line R can be obtained by direct screening in moderate to severe cadmium-polluted environment; or by cross breeding.

7. The method for breeding the rice hybrid variety with low cadmium content according to claim 6, wherein the hybrid breeding process of the restorer line R is as follows:

and (3) hybridizing the germplasm resource I with low cadmium content of rice serving as a female parent and the three-line restorer line resource II serving as a male parent, selfing the filial generation for 6-10 generations, and selectively breeding the restorer line R with low cadmium content of rice.

8. The method for breeding the hybrid rice variety with low cadmium content according to claim 7, wherein the hybridization can be an amphiphilic hybrid hybridization or a multi-parent compound hybridization; at least one of the hybridization parents is a parent with low cadmium content, and the other is a three-line restoring line parent.

9. The method for breeding the rice hybrid variety with low cadmium content according to claim 1, wherein the screening criteria in the step (1), the step (2) and the step (3) are as follows: screening with low content of cadmium in brown rice, cross-breeding, plant leaf type, and disease and stress tolerance as standard.

Technical Field

The invention belongs to the technical field of hybridization, and particularly relates to a breeding method of a rice hybrid variety with low cadmium content.

Background

The rice is the most important grain, and the breeding and large-area production application of the three-line hybrid indica rice greatly improve the single yield and the total yield of the rice in the rice region in south China, and make great contribution to ensuring the grain quantity safety in China and even the world. Cadmium is classified as a first carcinogen by the international cancer research organization, has great harm to human bodies, and has strict standard requirements on the cadmium content of main agricultural products in various countries. The cadmium pollution of farmland seriously affects the safe production of rice. Therefore, a breeding method capable of solving the problem of safe production of rice in cadmium-polluted farmland is urgently needed.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides a breeding method of a rice hybrid variety with low cadmium content, which aims to solve the problem of safe production of rice in the prior cadmium-polluted farmland. The application deeply researches the genetic effect of the cadmium content of the three-line hybrid indica rice and provides a technical route of three-line hybrid rice varieties which takes creation of breeding of the low-cadmium-accumulation sterile line as a key point. Through identifying the cadmium content of rice under the environment selection pressure of different cadmium pollution degrees of parents and hybrids, selecting cadmium low-accumulation germplasm resources to hybridize with maintainer line and restorer line materials by combining a traditional pedigree selection method, creating rice cadmium low-accumulation sterile line, maintainer line and restorer line hybrid parent materials; combining the traditional three-line heterosis utilization technology, combining the low cadmium accumulation characteristic of the rice of the three-line hybrid indica rice with the traditional yield quality resistance, and successfully breeding the three-line hybrid rice variety with low cadmium accumulation.

In order to achieve the purpose, the technical scheme adopted by the invention for solving the technical problems is as follows:

a breeding method of a rice hybrid variety with low cadmium content comprises the following steps:

(1) hybridizing the female parent and the male parent to obtain a filial generation F1, then culturing in a moderate-to-severe cadmium-polluted environment to obtain a progeny F2, selfing for at least 4 generations, and screening to obtain a maintainer line B with low cadmium content (the cadmium content is lower than 0.2 mg/kg); at least one of the female parent and the male parent is a parent with low cadmium content;

(2) hybridizing the sterile line as a female parent and the maintainer line B as a male parent to obtain a hybrid progeny F1, then continuously backcrossing the hybrid progeny F1 and the male parent maintainer line B for 6-10 generations, and screening to obtain a sterile line A;

(3) then, the low cadmium content restorer line R is used as a male parent, the sterile line A is used as a female parent for hybridization, and a hybrid variety with low cadmium content is obtained by screening.

Furthermore, the content of cadmium in the soil in the moderate-to-severe cadmium-polluted environment is 0.8-1.1 mg/kg.

Further, the hybridization in the step (1) is amphiphilic hybridization, and the female parent thereof is K42B with low cadmium content; the male parent is K17B variant line.

Further, the hybridization in the step (1) is multi-parent compound hybridization, at least one of the hybridization parents is a parent with low cadmium content, and at least one of the hybridization parents is a maintainer line parent; the parent is female parent or male parent. In the multi-parent compound hybridization, the hybridized parents are only a female parent and a male parent, but the hybridization is different from the hybridization of an two-parent compound, the two-parent compound hybridization has only one female parent and one male parent, and the multi-parent compound hybridization has a plurality of female parents and a plurality of male parents.

Further, the sterile line is indica rice sterile line K17A.

Further, the restorer line R can be obtained by directly screening in the moderate to severe cadmium polluted environment; or by cross breeding.

Further, the cross breeding process of the restorer line R is as follows:

and (3) hybridizing the germplasm resource I with low cadmium content of rice serving as a female parent and the three-line restorer line resource II serving as a male parent, selfing the filial generation for 6-10 generations, and selectively breeding the restorer line R with low cadmium content of rice.

Furthermore, the hybridization can be amphiphilic parent hybridization or multi-parent compound hybridization; at least one of the hybridization parents is a parent with low cadmium content, and the other is a three-line restoring line parent.

Further, the screening criteria in step (1), step (2) and step (3) are: screening with low content of cadmium in brown rice, cross-breeding, plant leaf type, and disease and stress tolerance as standard.

The invention has the beneficial effects that:

the method combines the traditional three-line heterosis utilization technology, applies three-line parent materials with low cadmium content of rice and excellent comprehensive properties, develops parent and hybrid seed breeding under the selection pressure of moderate cadmium pollution environment, creates a maintainer line, a sterile line and a restorer line with low cadmium accumulation of rice, and the cultivated hybrid rice variety integrates the characteristics of low cadmium accumulation of rice, high yield, high quality and the like.

Detailed Description

The following description of the embodiments of the present invention is provided to facilitate the understanding of the present invention by those skilled in the art, but it should be understood that the present invention is not limited to the scope of the embodiments, and it will be apparent to those skilled in the art that various changes may be made without departing from the spirit and scope of the invention as defined and defined in the appended claims, and all matters produced by the invention using the inventive concept are protected.