CN112369319A

CN112369319A - Method for breeding high-quality rice variety in high temperature period based on alkali elimination value

Info

Publication number: CN112369319A
Application number: CN202011259946.1A
Authority: CN
Inventors: 王慧; 张从合; 方玉; 严志; 黄艳玲; 杨力; 王林; 管昌红; 吴浩然; 陈思; 周桂香; 张云虎; 申广勒; 陈琳; 庞战士; 李方宝; 刘兴江
Original assignee: Shanghai Zhongke Quanyin Molecular Breeding Technology Co Ltd; Anhui Win All Hi Tech Seed Co ltd
Current assignee: Shanghai Zhongke Quanyin Molecular Breeding Technology Co Ltd; Anhui Win All Hi Tech Seed Co ltd
Priority date: 2020-11-12
Filing date: 2020-11-12
Publication date: 2021-02-19
Anticipated expiration: 2040-11-12
Also published as: CN112369319B

Abstract

The invention relates to a method for breeding high-quality rice varieties in a high-temperature period based on an alkali elimination value, belonging to the technical field of crop genetic breeding, and the method comprises the following steps: conventional rice varieties are used as parents, after hybridization and continuous selfing, the alkali elimination value and the fluctuation degree of the alkali elimination value are used as indexes for screening high-quality rice varieties in a high-temperature period, plants are graded in quality, the rice varieties with high quality are preferentially selected, and the selfing and screening steps are repeated until new high-quality rice varieties in the high-temperature period are obtained. The method firstly provides the method for breeding the high-quality rice variety in the high-temperature period by utilizing the alkali elimination value and the fluctuation degree of the alkali elimination value, and then the high-quality rice breeding material with high transparency and excellent taste is bred.

Description

Method for breeding high-quality rice variety in high temperature period based on alkali elimination value

Technical Field

The invention belongs to the technical field of crop genetic breeding, and particularly relates to a method for breeding a high-quality rice variety in a high-temperature period based on an alkali elimination value.

Background

Rice is one of the most important food crops in China and even the world, and more than half of the world population takes rice as staple food. In recent years, with the increasing living standard and consumption standard of people, the requirement for the quality of rice is higher and higher. In particular to the reform of the agricultural supply side structure, the method highlights the popularization of high-quality rice varieties, and leads the rice varieties and quality to better meet the market demand. At present, the varieties of low-end and medium-end rice in the market are sufficient, the varieties of high-quality and high-end rice with high transparency and good taste quality are relatively deficient, and a new rice variety with better rice quality is urgently needed in production.

However, as global climate becomes warmer, extremely hot weather is increasing. The continuous occurrence of large-area yield reduction and rice quality reduction events in rice production areas caused by high-temperature heat damage becomes one of the main factors for restricting the rice yield and quality. Aiming at the current situation that the high-temperature thermal damage of the rice is increasingly serious, a large amount of researches on a high-temperature resistant identification method of rice varieties and screening work on the high-temperature resistant rice varieties are also developed domestically, but no report is made on a method for screening high-quality rice varieties in a high-temperature period.

Therefore, how to rapidly and accurately breed the rice variety with excellent rice quality in the high-temperature period is an extremely important and urgent problem to be solved in the current rice breeding work.

Disclosure of Invention

The invention aims to solve the problems and provides a method for breeding a high-quality rice variety in a high-temperature period based on an alkali elimination value.

The invention realizes the purpose through the following technical scheme:

a method for breeding high-quality rice varieties in a high-temperature period based on an alkali elimination value comprises the following steps:

(1) hybridizing conventional rice varieties serving as parents to obtain F1 seeds;

(2) continuously selfing the F1 seeds for n-1 generation, screening excellent single plants according to the field agronomic characters in the selfing process, and harvesting Fn seeds;

(3) sowing Fn seeds and high-temperature-resistant high-quality control varieties in stages, and transplanting the seeds to a field after seedling raising;

(4) continuously recording the field temperature from the heading stage to the mature stage of each variety;

(5) after harvesting, airing and storing for 1 month in the mature period, taking the size of the alkali elimination value and the fluctuation degree of the alkali elimination value as indexes for screening high-quality rice varieties in the high-temperature period, and grading the quality of the Fn plants;

(6) and (4) preferentially selecting the high-quality rice variety graded in the step (5), and repeating the selfing and screening processes of the steps (2) to (5) until the high-temperature-stage high-quality rice variety with stable genetic characters is obtained.

As a further optimization scheme of the invention, the male and female rice varieties are indica rice varieties, and the high-quality rice varieties refer to varieties with high transparency and good cooking taste and quality.

As a further optimization scheme of the invention, the female parent is preferably Wushan Si Miao or self-bred YR338 of Anhuquan Yinjiao Gancao GmbH, the male parent is preferably self-bred high-quality rice YR0822 of Anhuquan Yinjiao Gancao GmbH, and the high-temperature-resistant high-quality control variety is preferably Fengliangyou No. 4, and the selection of the conventional rice variety is not limited to the above listed rice varieties.

As a further optimization scheme of the invention, in the step (2), n is more than or equal to 2.

As a further optimization scheme of the invention, in the step (2), the screening of the field agronomic characters refers to screening of rice varieties with one or more agronomic characters of short plant height, erect stalk type, high fruiting, good leaf type and good color cast.

As a further optimization scheme of the present invention, in the step (5), the method for screening by using the size of the alkali elimination value and the fluctuation degree of the alkali elimination value as the screening indexes comprises:

if the extremely high temperature weather occurs and all varieties have the starting spikes in the extremely high temperature weather, identifying by the judgment standard of the first method, and otherwise, identifying by the second method;

the method comprises the following steps: selecting the stage of the rice variety sowed in each stage, determining the alkali elimination value of the rice variety meeting extreme high temperature weather at the initial heading stage and recording the alkali elimination value of the high temperature resistant high-quality control variety as A_CK(ii) a If:

a is more than or equal to 6.5 or more than or equal to 6.0<6.5, and A-A_CKNot less than 0.5, the rice to be identifiedThe quality of the variety is excellent;

6.0≤A<6.5, and-0.5 is less than or equal to A-A_CK<0.5, the quality of the rice variety to be identified is good;

6.0≤A<6.5, and A-A_CK<-0.5, the quality of the rice variety to be identified is general;

a is less than 6.0, and the quality of the rice variety to be identified is poor;

the second method comprises the following steps: respectively measuring the alkali elimination value of each sowing time of the rice variety to be identified, and marking the maximum value as A_maxMinimum value is denoted A_minSimultaneously, measuring the average of alkali elimination values of all seeding periods of the high-temperature-resistant high-quality control variety, and recording as B; if:

A_minthe quality of the rice variety to be identified is excellent, and the rice variety to be identified is not less than 6.5;

6.0≤A_min<6.5, and A_max－A_minLess than or equal to 0.5; or A_max－A_minNot more than 0.5, and A_minThe quality of the rice variety to be identified is good when the rice variety is more than or equal to B;

A_max－A_min>0.5, and A_minThe quality of the rice variety to be identified is more than or equal to 6.0;

A_max－A_min>0.5, and A_min<6.0; or A_max－A_minNot more than 0.5, and A_min<6.0, and A_min<And B, the quality of the rice variety to be identified is poor.

As a further optimization scheme of the invention, the extreme high temperature weather is that the field temperature is continuously more than four days, and the maximum temperature is more than 37.5 ℃.

As a further optimization scheme of the invention, the staged sowing in the step (3) is sowing every 6 days.

As a further preferable embodiment of the present invention, the method for determining the alkali elimination value in step (5) includes the following steps:

(a) putting 6 mature and full polished rice grains into a square box of 5cm multiplied by 2cm, adding 10mL of 1.7 mass percent potassium hydroxide solution, uniformly distributing the rice grains in the square box by using a glass rod, and covering;

(b) placing the square box at the constant temperature of 30 +/-2 ℃ and preserving heat for 23 hours;

(c) observing the decomposition condition of rice endosperm one by one, and carrying out alkali elimination value grading record according to an alkali elimination value grading table to obtain an alkali elimination value:

rank of	Degree of decomposition	Definition of
			1	No change of rice grains	White with rice core
2	Swelling of rice grains	White with powder-like rings
			3	Swelling, incomplete or narrow rings of rice grains	White with a core, cotton-like or cloudy with rings
4	The rice grains are enlarged, and the rings are complete and wide	White, ring-like fog of rice core cotton
			5	Cracked rice grains with complete and wide rings	White cotton with rice core and clear ring cloud
6	The rice grains are partially dispersed and dissolved, and are fused with the ring	White cloud with no rings
			7	The grains are completely dispersed	The rice heart and the ring disappear

(d) Taking the average value of the rice grain grades which are repeated for many times as the alkali elimination value of the rice.

Meanwhile, standard samples with known alkali elimination values (the alkali elimination values are respectively 3 grades, 5 grades and 7 grades) are used as the internal standard samples for measurement, and the relative difference between the measured value and the known standard value of the internal standard sample is within 0.5 grade.

The invention has the beneficial effects that: the invention provides a method for breeding high-quality rice varieties in a high-temperature period based on an alkali elimination value, which is breeding and screening of the high-quality rice varieties in an extremely high-temperature weather. The method firstly provides the method for breeding the high-quality rice variety in the high-temperature period by utilizing the alkali elimination value and the fluctuation degree of the alkali elimination value, and then the high-quality rice breeding material with high transparency and excellent taste is bred.

Detailed Description

The present application is described in further detail below, and it should be noted that the following detailed description is provided for illustrative purposes only, and is not intended to limit the scope of the present application, which is defined by the appended claims.

Example 1

In this embodiment, for some rice materials of the limited Anhuquan Yinjiao Seiko, the high-quality rice varieties in the high-temperature period are identified by using the alkali digestion value, and meanwhile, the appearance quality and the cooking taste quality of the rice materials are determined by referring to the detection method specified in the quality of edible rice varieties (NY/T593-2013), and the comprehensive grade determination of the appearance and the cooking taste quality is performed to verify the feasibility of screening the high-quality rice varieties in the high-temperature period by using the alkali digestion value.

The verification process is divided into 2017 and 2018 for two years:

the rice variety identified in 2017 is as follows: II you 838, Yinhelimiao 0219, Quanyou822, Quanqieyu 1606, Yiqi810, Xinqieyu 611, Quanqieyu 851, the control variety: fengliyou No. 4. All seeds are provided by Anhuquan Gankao Seikagaku GmbH.

(1) And (3) stage sowing and transplanting management:

from 20 days in 4 months, the rice variety to be identified and the first-stage comparison variety are sown every 6 days, shown in table 1, and the common conventional water seedling raising management is adopted.

Table 1: stage sowing time table

Number of stages

First stage

Second stage

Stage III

Stage IV

Stage five

Stage six

Stage seven

Time of day

4 month and 20 days

4 month and 26 days

5 months and 2 days

5 month and 8 days

5 months and 14 days

5 months and 20 days

5 month and 26 days

All the varieties in the sowing period are sown in different periods, and the uniform plants are selected 20-30 days after sowing and then transplanted: each variety has 10 rows, each row has 10 plants, the total number of the plants is 100, the outermost row of each variety is a protection row, and the high-yield cultivation management is carried out according to the conventional method.

(2) Temperature data recording: the highest daily temperature and the average daily temperature of the field are continuously recorded from the heading stage to the mature stage of all the rice varieties in all the sowing periods sowed in different periods, wherein the recording condition of the highest daily temperature of the field above 37.5 ℃ is shown in Table 2.

Table 2: extreme high temperature documentation

Date	Maximum air temperature	Date	Maximum air temperature
				7 month and 21 days	38℃	7 month and 26 days	40℃
7 month and 22 days	39℃	7 month and 27 days	40℃
				7 month and 23 days	39℃	7 month and 28 days	39℃
7 month and 24 days	40℃	7 month and 29 days	38℃
				7 month and 25 days	41℃

(3) Harvesting and airing: after the protective row is removed, all the rice varieties in the sowing period are sown in different periods until the rice varieties in the mature period are harvested respectively, and the rice varieties are aired and stored for 1 month.

(4) Variety evaluation by selection mode: the maximum temperature of the field is more than 37.5 ℃ for more than four consecutive days from 21 days in 7 months to 29 days in 7 months, and all varieties begin to spike at the high temperature stage, so the judgment standard of the first selection method is used for judgment, and the method specifically comprises the following steps:

selecting a stage of rice varieties sowed in each stage when the heading stage meets extreme high-temperature weather, and recording the measured alkali elimination value as A; the alkali elimination value of the high-temperature resistant high-quality control variety Fengliou No. 4 is recorded as A_CK。

And (3) alkali elimination value determination: rice varieties are hulled into polished rice, 6 mature and full polished rice grains are placed in a square box of 5cm multiplied by 2cm, and 10mL of potassium hydroxide solution with the mass percent of 1.7% is added. Uniformly arranging the rice grains in the box by using a glass rod, then covering the box, and repeating the same variety for three times; the square box is stably moved into a constant temperature box with the temperature of 30 +/-2 ℃, and is stably taken out after heat preservation for 23 hours; observing the decomposition condition of rice endosperm one by one, and recording the decomposition condition in a grading table according to the alkali digestion value; taking the average value of the alkali elimination values of 18 grains of rice in three times of repetitions as the alkali elimination value of the rice. At the same time, standard samples with known alkali elimination values (grade 3, 5 and 7 respectively) were used as internal standard samples to perform measurement together. The relative difference between the measured value of the internal standard sample and the known standard value is within 0.5 grade.

The results of the determination of the alkali elimination value of the first-stage rice in the heading stage of the rice variety to be identified and the reference variety in the extremely high temperature weather and the evaluation of the results are shown in Table 3.

Table 3: alkali elimination value measurement results and evaluation results

The intermediate materials identified in 2018 are all improved progeny of Quan211S, namely intermediate materials obtained by selfing 4 times after hybridizing once in 2016 spring fertility with high-quality indica two-line sterile line Quan211S as a female parent and Wushan Miao as a male parent, and the serial numbers are as follows: QY-01, QY-02, QY-03, QY-04, QY-05, QY-06, QY-07, QY-08, QY-09, control varieties: fengliyou No. 4. All seeds are provided by Anhuquan Gankao Seikagaku GmbH.

And (4) performing stage sowing, seedling raising and transplanting, temperature recording, harvesting and airing according to the screening method of 2017. In 2018, the temperature of the field is not continuously more than four days, the highest temperature is more than 37.5 ℃, and all the varieties have no spike initiation in all the sowing periods in the extremely high temperature weather, so the screening is carried out according to the judgment standard of method two.

Respectively measuring the alkali elimination value of each sowing time of the rice variety to be identified, and marking the maximum value as A_maxMinimum value is denoted A_min(ii) a And simultaneously, measuring the average of the alkali elimination values of all the sowing periods of the high-temperature-resistant high-quality control varieties, and recording as B.

Table 4: alkali elimination value measurement result

Table 5: the evaluation result of the quality of the rice material in the high-temperature period is as follows:

selecting the second best 838, the second best silky seedling, the second best 0219, the second best 822, the second best 1606, the second best 810, the new second best 611 and the second best 851 in the first period meeting extreme high temperature weather at the heading stage, and the first period with the minimum alkali elimination value of QY-01, QY-02, QY-03 and QY-04, and determining the transparency, the whiteness, the amylose content, the alkali elimination value and the glue consistency of each variety according to a detection method specified in quality of the indica rice varieties (NY/T593-2013), and performing comprehensive evaluation according to the quality grades of the indica rice varieties, wherein the detection results and the grade judgment are shown in the following table 6.

Table 6: appearance and cooking taste quality measurement results and grade judgment

As can be seen in Table 6, the rice varieties judged as the first grade in the comprehensive grades of appearance and cooking taste quality are Yinhelimiao, Quanliangyou 1606, Xinliangyou 611, QY-02 and QY-04; the rice varieties judged as second grade by the comprehensive grades of appearance and cooking taste quality are Quanliangyou 822, Quanliangyou 851 and Fenliangyou 4 (CK); the rice varieties except the rice varieties with the appearance and the cooking taste quality judged by the comprehensive grade are II best 838, Yinyangyou 0219, Yinyouyou 810, QY-01 and QY-03. The result is consistent with the screening result of the alkali elimination value.

Example 2

The embodiment provides a method for breeding a new high-quality rice restorer line variety YR1606 in the high temperature period by taking the self-breeding restorer line YR338 of the Anhuquan Yinjiao Gaoyuan Co., Ltd as a female parent and the YR0822 as a male parent. Wherein:

the female parent 'YR 338' is an intermediate material with good quality and good agronomic characters, which is preferably selected in 2009 by the Anhuquan Gaojian province limited company in 2006 spring, continuously selfing six generations after the third generation of the female parent 'Nanhui 511' with good rice quality and good comprehensive characters is hybridized with the self-breeding restorer 'YR 1671' of the Anhuquan Gaojian province limited company;

the male parent is restorer line 'YR 0822' (variety weight: CNA20120661.2) with good self-breeding agronomic character, prematurity, rice blast resistance (containing rice blast resistance gene Pi-2) and good quality;

control variety: fengliyou No. 4.

The breeding method comprises the following steps:

(1) carrying out conventional sexual hybridization in the spring of 2013 in Hainan III with YR338 as a female parent and a high-quality rice restorer YR0822 as a male parent to obtain F1 seeds;

(2) planting F1 seeds in the Anhui fertilizer in 2013 summer, selecting excellent single plants with short plant height, upright stalk type, high fruit set, good plant leaf type and good color cast through field agronomic character screening, and obtaining F2 seeds through mixed harvest;

(3) continuing to plant the F2 seeds in the step (2) in the third Hainan province in 2014, continuing to screen the F2 population for field agronomic characters, selecting 100 parts of excellent single plants with short plant height, upright stalk type, high fruit set, good plant leaf type and good color cast, and harvesting to obtain F3 seeds;

(4) continuously planting the F3 seeds in the step (3) in summer of 2014 in Anhui compost, continuously screening the F3 population for field agronomic characters, selecting 60 parts of excellent single plant lines with short plant height, upright stalk type, high fruit, good plant leaf type and good color cast, and harvesting to obtain F4 seeds;

(5) and (3) continuously planting the F4 seeds in the Hainan III in 2015 spring, preferably 30 parts of single plants with excellent agronomic characters, and harvesting to obtain F5 seeds.

(6) In summer 2015, in Anhui fertilizer combination, F5 seeds were subjected to:

s1: f5 seeds and a high-temperature-resistant high-quality control variety Fengliangyou No. 4 are sown in stages, and the seeds are transplanted to a field after seedling cultivation.

S2: the temperature of the field is continuously recorded from the heading stage to the mature stage of each variety.

S3: harvesting, air drying and storing for 1 month in the mature period;

s4: the size of the alkali elimination value and the fluctuation degree of the alkali elimination value are used as indexes for screening high-quality rice varieties in the high-temperature period, the quality of the rice varieties is graded, and the specific judgment standard refers to example 1 and is not described repeatedly herein.

When the first alkali elimination value screening is carried out, the highest temperature of the field is more than 37.5 ℃ for more than four days continuously from the heading stage to the mature stage of all the rice varieties in all the sowing stages sowed in each stage, so the judgment is carried out by the judgment standard of the second judgment method.

(7) In the third Hainan year of 2016, F6 seeds with high rice quality in the high-temperature stage in the step (6) are preferably selected for continuous planting, selfing is carried out for 1 time, and F7 seeds are obtained;

(8) in 2016, in summer, the screening process in the step (6) is repeated for the F7 seeds;

in the second time of screening the alkali digestion value, the highest temperature of the field is more than 37.5 ℃ for more than four consecutive days according to the temperature data record (shown in table 7), and all varieties have the heading at the high temperature stage, so the judgment is carried out by the first judgment standard of the selection method. High-quality rice materials in the high-temperature period are preferentially selected to obtain a new high-quality indica rice variety in the high-temperature period, which is named as YR 1606.

Table 7: extreme high temperature documentation

Date	Maximum air temperature	Date	Maximum air temperature
				7 month and 24 days	38℃	7 month and 28 days	39℃
7 month and 25 days	38℃	7 month and 29 days	38℃
				7 month and 26 days	38℃	7 month and 31 days	38℃
7 month and 27 days	39℃

Example 3

The embodiment provides a method for breeding a new high-quality rice restorer line quanhui 82 in the high-temperature period by taking Wushan Si Miao as a female parent and YR0822 as a male parent. Wherein:

the female parent 'Wushan Miao' has a roughness of 78.8%, a whole rice rate of 62.5%, an aspect ratio of 3.0, a chalkiness degree of 1.9%, an amylose content of 16.6%, a glue consistency of 70mm, a thousand-grain weight of 23.6g, a rice blast resistance (containing a rice blast resistance gene Pi-2), Guangdong approval in 2009 (Yue examine rice 2009031), and an approval in 2016 (Wan rice 2016055)

control variety: fengliyou No. 4.

The breeding method comprises the following steps:

(1) in the summer of 2014, Anhui rice hybrid fertilizer is prepared by carrying out conventional sexual hybridization on Wushan rice seedling serving as a female parent and high-quality rice restorer line YR0822 serving as a male parent to obtain F1 seeds.

(2) Planting F1 seeds in Hainan III in 2015 spring, screening field agronomic characters, selecting excellent single plants with good plant leaf morphology, and harvesting to obtain F2 seeds;

(3) continuously planting the F2 seeds in the step (2) in summer of 2015 in the Anhui compost, continuously carrying out field agronomic character screening on the F2 population, selecting excellent single plants with good plant leaf morphology, and harvesting to obtain F3 seeds;

(4) and (4) continuing planting the F3 seeds in the step (3) in the third Hainan year of 2016, continuing screening the F3 population for field agronomic characters, selecting excellent single plants with better plant leaf morphology, and harvesting to obtain F4 seeds.

(5) In 2016 summer, in Anhui compost, F4 seeds were subjected to:

s1: f4 seeds and a high-temperature-resistant high-quality control variety Fengliangyou No. 4 are sown in stages, and the seeds are transplanted to a field after seedling cultivation.

S2: the field temperature was continuously recorded for each variety from the heading stage to the maturity stage (see table 7 of example 2).

S3: harvesting, air drying and storing for 1 month in the mature period;

s4: and (3) taking the size of the alkali elimination value and the fluctuation degree of the alkali elimination value as indexes for screening high-quality rice varieties in the high-temperature period, and grading the quality of the rice varieties.

When the first time of alkali digestion value screening is carried out, the maximum temperature of the field is more than 37.5 ℃ for more than four consecutive days, and all varieties begin to spike at a high temperature, so that the judgment is carried out by selecting a judgment standard of a first method.

(6) F5 seeds with high-quality rice in the high-temperature stage in the step (5) are preferably selected from Hainan in spring of 2017 to be continuously planted, and the step (2) is repeated for selfing for 1 time to obtain F6 seeds;

(7) and (3) in summer of 2017, mixing fertilizers in Anhui, planting the F6 seeds in the step (6), and repeating the step (5), wherein the temperature data of S2 is recorded (see table 2 in example 1), and the judgment standard of the first method is selected for judgment in S4. Preferably selecting high-quality rice material in the high-temperature period to obtain high-quality indica rice variety named as Quanhui 82.

The parent and the parent of the examples 2 and 3 and the newly bred varieties "YR 1606" and "quanhui 82" were subjected to quality measurement by using a detection method (NY/T593-2013) specified in "quality of edible rice varieties" (NY/T593-2013), transparency, whiteness, amylose content, alkali elimination value and gel consistency of each variety were measured, and comprehensive evaluation was performed with reference to quality grades of indica rice varieties, and the detection results and grade determinations are shown in table 8 below.

Table 8: appearance and cooking taste quality measurement results and grade judgment

As can be seen from Table 8, the comprehensive grades of the appearance and the cooking taste quality of the YR1606 and the Quanhui 82 obtained by breeding by the breeding method of the present invention are judged to be first grade, and high-quality rice in the high temperature period is successfully obtained.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the present invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention.

Claims

1. A method for breeding high-quality rice varieties in a high temperature period based on an alkali elimination value is characterized by comprising the following steps:

2. The method for breeding the high-quality rice variety in the high-temperature period based on the alkali digestion value as claimed in claim 1, wherein the male parent rice variety and the female parent rice variety are indica type rice varieties, and the high-quality rice variety refers to a variety with high transparency and good cooking taste quality.

3. The method for breeding the high-quality rice variety in the high-temperature period based on the alkali elimination value as claimed in claim 2, wherein the female parent is a Wushan rice seedling or YR338 rice variety, the male parent is a high-quality rice variety YR0822, and the high-temperature-resistant high-quality control variety is Fengliangyou No. 4.

4. The method for breeding the high-quality rice variety in the high-temperature period based on the alkali elimination value as claimed in claim 1, wherein n is more than or equal to 2 in the step (2).

5. The method for breeding the high-quality rice variety in the high-temperature period based on the alkali elimination value as claimed in claim 1, wherein the screening of the field agronomic characters in the step (2) refers to screening of the rice variety with one or more of short plant height, erect stalk type, high fruit set, good leaf type and good color cast.

6. The method for breeding the high-quality rice variety in the high-temperature period based on the alkali elimination value as claimed in claim 1, wherein the method for screening by using the size of the alkali elimination value and the fluctuation degree of the alkali elimination value as the screening indexes in the step (5) comprises the following steps:

a is more than or equal to 6.5; or 6.0. ltoreq.A<6.5, and A-A_CKNot less than 0.5, the quality of the rice variety to be identified is excellent;

7. The method for breeding the high-quality rice variety in the high-temperature period based on the alkali digestion value as claimed in claim 6, wherein the maximum temperature in the extreme high-temperature weather is above 37.5 ℃ for more than four consecutive days of field temperature.

8. The method for breeding the high-quality rice variety in the high-temperature period based on the alkali elimination value as claimed in claim 1, wherein the staged seeding in the step (3) is one stage every 6 days.

9. The method for breeding the high-quality rice variety in the high-temperature period based on the alkali elimination value as claimed in claim 1, wherein the method for measuring the alkali elimination value in the step (5) comprises the following steps: