CN105104168A - Hybrid rice breeding method using parents with close duration from seeding to heading - Google Patents

Abstract

The invention discloses a hybrid rice breeding method whose parents have similar sowing start and duration, and belongs to the field of hybrid rice breeding. The hybrid rice breeding method of the present invention uses different rice parents with similar sowing start dates and far genetic distances to improve the rice sterile lines and restorer lines, and sows in stages under different ecological environment conditions to obtain similar sowing start dates and agronomic CMS lines and restorer lines with stable traits are then testcrossed, the testcross F ₁ generation is planted, and a hybrid combination with excellent traits is selected, that is, a hybrid rice with a growth period similar to that of the parents. The method of the invention ensures that the male parent and the female parent meet at the flowering stage when sowing at the same time, and improves the reliability of seed production; meanwhile, it is also conducive to the mechanization of field operations, reduces the dependence on labor, saves costs, and improves the seed production efficiency.

Description

Breeding method of hybrid rice whose parents have similar sowing start period

technical field

The invention relates to a hybrid rice breeding method, in particular to a hybrid rice breeding method whose parents have similar sowing start periods, and belongs to the field of hybrid rice breeding.

Background technique

Rice is the main food crop in China. At present, the annual rice planting area is about 430-440 million mu, of which the annual planting area of hybrid rice is about 220 million mu, accounting for more than 50% of the total rice area, which contributes to the substantial increase in rice production and food security in China. made a great contribution.

At present, most of the hybrid rice combinations promoted in China have a relatively large difference in the sowing start period (the number of days from sowing to the beginning of heading) between the male parent (restorer line) and the female parent (sterile line) (generally, the male parent period is long, and the reproductive period of the female parent is short). When making seeds, in order to make the male parent and the female parent meet at the flowering period to produce the F1 generation of hybrids (that is, commercial hybrids), it is necessary to sow the parent (male parent) with a long sowing period, according to the sowing history of the male parent and the female parent. The number of days difference between the two periods is different, and then the parent (female parent) with a short duration of sowing is sown, so that the male parent and the female parent can head, flower and pollinate at the same time. On the one hand, this leads to out-of-synchronization of the transplanting of the parents, and the field operation is basically dependent on manual labor, with a large amount of labor and high costs, making it difficult to adapt to the current situation of reduced human resources engaged in agricultural labor; It often fluctuates due to inter-annual climate differences. Even if the sowing date of the parents is adjusted according to historical experience, the phenomenon that the parents' flowering period does not meet still occurs from time to time, and the seed production output is difficult to guarantee.

Therefore, the mechanization of simultaneous sowing and production of parents is an effective way to ensure the yield and efficiency of hybrid rice seed production, reduce production costs and improve the competitiveness of hybrid rice production technology.

Contents of the invention

The technical problem to be solved by the present invention is to provide a hybrid rice breeding method with similar parental sowing periods, the method is by sowing in stages under different ecological environment conditions, and selects the male parent whose sowing period is similar to the same climate response ( Restorer line) and female parent (sterile line), the mating group was tested, and a new combination of dominant hybrid rice was cultivated to ensure that the male parent and the female parent met at the flowering stage when sowing at the same time, so as to improve the reliability of seed production and increase the efficiency of seed production; at the same time It is also conducive to adapting to the mechanization of field operations, reducing the dependence on labor and saving costs.

In order to solve the problems of the technologies described above, the technical solution adopted in the present invention is:

The invention discloses a method for breeding hybrid rice whose parents have similar initial sowing periods, comprising the following steps: (1) breeding restorer lines and sterile lines with similar initial sowing periods, and then using the sterile lines as female parents and Test cross the restorer line to obtain the test cross F ₁ generation; (2) select the test cross F ₁ generation with good traits, and obtain it.

Wherein, the test cross F ₁ generation is planted under high temperature and long day conditions; preferably, wherein the high temperature and long day conditions are May-October in Hefei. The testcross F ₁ generation with excellent agronomic traits is selected, that is, the hybrid rice with a similar growth period to the parents.

The selection of restorer lines and sterile lines with similar sowing duration described in step (1) includes:

(1) Using the sterile line' as the female parent to cross with the rice parent to obtain the hybrid F ₁ generation;

(2) using the sterile line '' described in step ( ₁ ) as the recurrent parent to backcross the hybrid F1 generation to obtain backcross offspring; self _- cross the backcross offspring to obtain BC _n F2 populations;

(3) Using the restorer line ' as the female parent to cross with the rice parent' to obtain the hybrid F ₁ 'generation;

(4) Using the restorer line' described in step (3) as the recurrent parent to backcross with the hybrid F ₁ 'generation to obtain a backcross offspring'; self-cross the backcross offspring' to obtain a BC _n F ₂ 'population;

(5) sowing BC _n F ₂ population and BC _n F ₂ ' population respectively, selfing for multiple generations until the agronomic traits are stable, and selecting restorer lines and sterile lines with similar sowing start periods, to obtain the product;

or,

(a) using the sterile line' as the female parent to cross with the rice parent to obtain the hybrid F ₁ generation;

(b) selfing the hybrid F ₁ generation to generate F ₂ populations;

(c) using the restorer line ' as the female parent to cross with the rice parent' to obtain the hybrid F ₁ 'generation;

(d) selfing the hybrid F ₁ ' generation to generate F ₂ 'population;

(e) Sow the F ₂ population and the F ₂ ' population separately, and self-cross for multiple generations until the agronomic traits are stable, and select and breed restorer lines and sterile lines with similar sowing start periods.

Wherein, the rice parent described in step (1) and the rice parent ' described in step (3) have a similar sowing period, and the genetic distance is relatively far; the rice male parent described in step (a) and the rice described in step (c) The male parent's sowing period is similar, and the genetic distance is far. The backcross in step (2) or step (4) is 1-3 generations of backcross; the self-cross is 1 time of self-cross. The sowing start period described in the present invention is similar to the difference of less than or equal to 2 days in the sowing start period.

Further, as described in step (5), the BC _n F ₂ population and the BC _n F ₂ ' population are respectively sown, and self-crossed for multiple generations until the agronomic traits are stable, and the restorer line and the sterile line with a similar initial period of sowing are selected, Include the following steps:

(I) Under high temperature and long-day conditions, sow and transplant BC _n F ₂ populations and BC _n F ₂ ' populations (more than 2000 plants each) at the same time, and select individual plants with similar initial heading stages and excellent traits in the two populations , to harvest the candidate individual plant seeds;

(II) In the same year, under low temperature and short day conditions, the seeds harvested by the two populations in the step (I) were sown and transplanted at the same time, planted in rows, and single plants with similar initial heading stages and excellent traits were selected, and harvested seed;

(Ⅲ) In the next year, under high temperature and long day conditions, simultaneously sow and transplant the seeds harvested in the step (II) respectively, and plant the adult plant rows, select the single plants with similar initial earing stage and good character, and harvest the candidate singles plant seeds;

(Ⅳ) repeating step (II) and step (Ⅲ) until the selected individual plant traits are stable, harvesting seeds respectively;

(Ⅴ) The seeds harvested in step (Ⅳ) are sown and transplanted in stages under high temperature, long-day conditions and low temperature, short-day conditions respectively, and the lines with similar initial earing stages are selected in each same sowing date, respectively. CMS and restorer lines;

(Ⅵ) The sterile line selected in the step (Ⅴ) is subjected to the fertility identification, and it is obtained.

Wherein, the harvesting of candidate single plant seeds in step (I) includes: selecting pollen-sterile or pollen-free single plants in the BC _n F ₂ population, cutting stubble, and transplanting to regenerate, and harvesting the individual plants on the regenerated plants Seeds; for the selected individual plants in the BC _n F ₂ 'population, directly harvest the individual plant seeds; the harvesting of candidate individual plant seeds as described in step (Ⅲ) includes: for the selected individual plants of the offspring of the BC _n F ₂ population, select pollen not For a single plant with or without pollen, cut stubble and transplant to produce ratooned rice, and harvest the seeds on the corresponding single plant; for the single plant of the offspring of the BC _n F ₂ ' population, directly harvest the single plant seed; preferably, wherein the cut The stubble is rice stubble height 15-20cm. The harvesting of seeds described in step (II) and step (IV) is the direct harvesting of single plant seeds.

_In the step (e), sow the F2 population and the F2' population respectively, and self _- cross for multiple generations until the agronomic traits are stable, and select a restorer line and a sterile line with a similar initial sowing period, including the following steps:

(I) Under high temperature and long-day conditions, sow and transplant F2 populations and F2' populations (more _than 2000 plants each ₎ at the same time, select individual plants with similar initial heading stages and excellent traits in the two populations, and harvest candidate singles plant seeds;

(II) In the same year, under low temperature and short-day conditions, the seeds of the two populations harvested in the step (I) were sown and transplanted simultaneously, planted in rows, and the individual plants with similar initial heading stages and excellent traits were selected, and harvested seed;

(Ⅲ) In the next year, under high temperature and long day conditions, simultaneously sow and transplant the seeds harvested in the step (II) respectively, and plant the adult plant rows, select the single plants with similar initial earing stage and good character, and harvest the candidate singles plant seeds;

(Ⅳ) repeating step (II) and step (Ⅲ) until the selected individual plant traits are stable, harvesting seeds respectively;

(Ⅴ) The seeds harvested in step (Ⅳ) are sown and transplanted in stages under high temperature, long-day conditions and low temperature, short-day conditions respectively, and select lines with similar initial earing stages in each same sowing date, respectively Selected sterile lines and restorer lines;

(Ⅵ) The sterile line selected in the step (Ⅴ) is subjected to the fertility identification, and it is obtained.

Wherein, the harvesting of candidate individual plant seeds in step (I) includes: selecting pollen-sterile or pollen _- free individual plants in the F2 population, cutting the stubble, and transplanting to regenerate, and harvesting the seeds on the regenerated plants from individual plants; For the individual plants selected in the F ₂ 'population, directly harvest individual plant seeds; the harvesting of candidate individual plant seeds as described in step (Ⅲ) includes: selecting pollen-sterile or pollen-free individual plants for the selected individual plants of the F ₂ population progeny , cutting stubble, transplanting to produce ratooned rice, and harvesting the seeds on the corresponding individual plant; for the individual plant of the offspring of the F ₂ ' population, directly harvesting the individual plant seed; preferably, wherein the stubble cutting is rice stubble height 15-20cm . The harvesting of seeds described in step (II) and step (IV) is the direct harvesting of single plant seeds.

The start ear stage of the present invention is similar to be that sowing beginning period differs≤2 days; Described high temperature, long day condition are 4-10 months of Hefei, are preferably Hefei 5-10 month; Described low temperature, short day condition are 11-12 months in Hainan; the staged sowing described in step (Ⅴ) is divided into 6 stages of sowing, and 1 stage is sown every 10 days; specifically, the staged sowing can be under high temperature and long day conditions, and the sowing period is 4/5 20, 4/30, 5/10, 5/20, 5/30, 6/9; under low temperature and short day conditions, the sowing period is 11/10, 11/20, 11/30, 12/10, 12 /20, 12/30; the transplanting is 30 days after sowing, and transplanting at the same time; the fertility identification of step (Ⅵ) is in accordance with the "Rice Light, Temperature Sensitive Male Genic Male Sterile Line Fertility Identification Regulations NY/T1215- 2006NY/T1215-2006" was carried out.

The stable character of the present invention means that the selected single plant does not segregate its character. The excellent traits of the present invention include high yield, strong resistance to diseases and insect pests, good quality, early maturity or late maturity and other agronomic traits, which can be determined according to the breeding objectives.

The hybrid rice breeding method of the present invention, said sterile line comprises: dual-purpose nuclear sterile line N876S (Guangzhan 63 improved strain, sowing period of 75-80 days); said rice parent comprises: Huang Huazhan (Huang Xinzhan/ Fenghua occupies the F5 generation, bred by the Rice Research Institute of the Guangdong Academy of Agricultural Sciences), 14C195 (a high-generation material selected by Yangdao 6/RH003, bred by the Rice Research Institute of the Anhui Academy of Agricultural Sciences); the restorer lines include: 13np34 (A stable strain was obtained by mutagenizing Yangdao No. 6, and the sowing period was about 100 days).

The present invention has no special restrictions on the sterile lines, restorer lines and rice parents, and the excellent sterile lines and restorer lines commonly used in production, as well as satisfying the requirement that the sowing start date is similar (the difference between the sowing start date ≤ 2 days), and the genetic distance is relatively small. All rice germplasms far away are suitable for the present invention.

The hybrid rice selection method of the present invention is compared with the traditional rice selection method, and the results show that the traditional hybrid rice selection requires manual sowing and manual transplanting of the parents in stages due to the difference in the sowing start period of the male parent and the female parent. The quantity is large, the cost is high, and the field operation is basically dependent on labor, which is inefficient; and due to the inter-annual climate difference, the risk of parental flowering period is high, and the seed production output is difficult to guarantee. However, the growth period of the parents of the hybrid rice combination of the present invention is similar (difference between the beginning and end of sowing≤2 days), mechanical mixed sowing does not need to transplant the parents, and realizes the mechanization of simultaneous sowing and production of the parents, with a small amount of labor and low cost. The seed production efficiency is high; moreover, the flowering period of the parents meets, which reduces the risk that the flowering period of the parents does not meet, and ensures the yield of hybrid rice seed production.

Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

The present invention sows in stages under different ecological environment conditions, selects the male parent (restorer line) and the female parent (sterile line) that respond similarly to the same climate at the beginning of sowing, and tests the mating group to cultivate a new combination of dominant hybrid rice. It can ensure that the flowering period of the male parent and the female parent meet at the same time sowing, and improve the reliability of seed production; at the same time, it is also suitable for mechanization of field operations, reducing the dependence on agricultural materials and labor, saving costs, and improving seed production efficiency.

Definition of terms involved in the present invention

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

The "sowing period" refers to the number of days from sowing to heading of rice.

The "sterile line" includes "three-line sterile line" and "two-line sterile line". The three-line sterile line means that the selected male sterile individual plants are crossed with fertile individuals and then cultivated through continuous backcrossing, which has the characteristics of male sterility and uniform quality. The two-line sterile line refers to the light-temperature-sensitive sterile line. Its fertility conversion is closely related to the length of sunshine and the temperature. It shows male sterility under long-day high-temperature conditions; fertile.

"Restorer line" refers to a line that can restore male fertility to offspring after crossing a line with a sterile line.

"Backcrossing"means that a hybrid produced by crossing two parents is crossed with one of the parents. Generally, a variety with excellent characteristics is selected as the female parent in the first hybridization, and is used as the male parent in each subsequent backcrossing. This parent is called the reincarnation parent in the backcrossing.

"Selfing" means the union of male and female gametes from the same individual or mating between individuals of the same genotype or mating between individuals from the same clonal line.

"Test cross", in rice, refers to the use of a sterile line as the female parent, crossing with different restorer lines, measuring the combining ability of the parents, and selecting a hybrid combination with strong first-generation heterosis.

"Genetic distance" is an index to measure the comprehensive genetic difference of several traits among varieties. There is more than one trait required for breeding goals. In order to reflect the genetic differences between parental varieties more comprehensively, multiple traits need to be considered comprehensively, thus leading to the concept of genetic distance. According to the multivariate statistical analysis method, the geometric distance of the multi-dimensional space composed of multiple trait genotype values between varieties is calculated, which is called the genetic distance between varieties.

Description of drawings

Figure 1 shows the breeding process of hybrid rice with similar sowing start period of the parents.

Detailed ways

The present invention will be further described below in conjunction with specific embodiments, and the advantages and characteristics of the present invention will become clearer along with the description. However, it should be understood that the described embodiments are only exemplary and do not constitute any limitation to the scope of the present invention. Those skilled in the art should understand that the details and forms of the technical solution of the present invention can be modified or replaced without departing from the spirit and scope of the present invention, but these modifications or replacements all fall within the protection scope of the present invention.

The breeding of embodiment 1 hybrid rice

(1) Select Huanghuazhan, a parent with a similar sowing start period (about 90 days in Hefei) and a relatively distant genetic distance (Huang Xinzhan/Fenghuazhan F5 generation, bred by the Rice Research Institute of Guangdong Academy of Agricultural Sciences and sold to the outside world) , 14C195 (advanced material bred by Yangdao 6/RH003, bred by the Rice Research Institute of Anhui Academy of Agricultural Sciences and sold to the outside world);

(2) Using the self-fertile dual-purpose nuclear sterile line N876S of the Rice Research Institute of Anhui Academy of Agricultural Sciences (sold by the Rice Research Institute of Anhui Academy of Agricultural Sciences) as the female parent (Guangzhan 63S as the female parent, crossed and backcrossed with Minghui 63 After selfing (BC ₁ F ₃ ), the obtained two-line sterile line, which lasted 75-80 days since sowing) was crossed with Huang Huazhan to obtain a hybrid F ₁ (S). And N876S was used as the recurrent parent to continuously backcross the hybrid F ₁ (S) for 2 generations to produce BC ₂ F ₁ (S) seeds;

(3) The material 13np34 (bred and sold by the Rice Research Institute of Anhui Academy of Agricultural Sciences) obtained by mutagenesis with golden shell and golden internodes (using 0.5% EMS (methylsulfonic acid) Ethyl ester) was used to treat Yangdao 6, a stable line was obtained in the second generation of mutagenesis, and the sowing period was about 100 days) as the female parent and 14C195 to obtain a hybrid F ₁ (R), and 13np34 was used as the recurrent parent and the hybrid F ₁ (R) was continuously backcrossed to produce BC ₁ F ₁ (R) seeds;

(4) Hefei, sow and transplant BC ₂ F ₂ (S) and BC ₁ F ₂ (R) seeds (more than 2000 plants each) at the same time on May 5, and select the first panicle in the two populations on August 10-15 Individual plants with similar growth periods (difference between sowing start and duration ≤ 2 days) and excellent agronomic traits were marked. Perform microscopic examination on individual plants selected in the BC ₂ F ₂ (S) population, select individual plants without pollen, cut stubble, and transplant to another field for isolated planting to regenerate, and harvest mature plants on the regenerated plants. Seed BC ₂ F ₃ (S) generation; for a single plant selected in the BC ₁ F ₂ (R) population, the seed of a single plant BC ₁ F ₃ (R) generation is directly harvested when mature.

(5) In the same year, Hainan, on November 20-25, the individual plants selected by the two populations in step (4) were sown at the same time, and planted into adult rows (150-200 plants), and the selection of the initial earing period was similar (the sowing period A single plant with a difference of ≤2 days) and excellent agronomic properties should be harvested.

(6) Next year, in Hefei, sow on May 5-10, plant in rows (150-200 plants), and select individual plants with similar initial earing stages (difference between sowing and initial stages ≤ 2 days) and excellent agronomic properties. For the selected single plant of BC ₂ F ₁ (S) progeny, microscopic examination of pollen after the first panicle, the single plant without pollen was cut and transplanted to produce ratooning rice, and the seeds on the corresponding single plant were harvested; for BC ₁ F ₁ (R) The individual plants of the progeny are harvested directly after maturity.

(7) Step (5) and step (6) are repeated until the agronomic traits of the selected single plant are stable, and a sufficient number of seeds are collected.

(8) The seeds of the two offspring of BC ₂ F ₁ (S) and BC ₁ F ₁ (R) harvested in step (7) were sown in stages in Hefei and Hainan, respectively. The sowing dates in Hefei are 4/20, 4/30, 5/10, 5/20, 5/30, 6/9; the sowing dates in Hainan are 11/10, 11/20, 11/30, 12/10, 12/ 20, 12/30. In each sowing date, the lines with similar initial heading stages (difference between sowing and initial stages ≤ 2 days) were selected.

(9) With reference to the "Rice Light and Temperature Sensitive Male Genic Male Sterile Line Fertility Identification Regulations NY/T1215-2006NY/T1215-2006", the selected CMS line is subjected to fertility identification, and the CMS line that meets the standard is selected;

(10) take the sterile line selected in the step (9) as the female parent, test cross with the restorer line selected in the step (8), plant and observe the agronomic traits of the test cross F ₁ generation in Hefei (5-10 months), The F1 generation with excellent agronomic traits is selected, which is _a new hybrid rice variety with a similar growth period to the parents.

The breeding of embodiment 2 hybrid rice

(1) Select Huanghuazhan (F5 generation of Huangxinzhan/Fenghuazhan, bred by Rice Research Institute of Guangdong Academy of Agricultural Sciences), 14C195( The high-generation material selected by Yangdao 6/RH003 was bred by the Rice Research Institute of Anhui Academy of Agricultural Sciences and sold to the outside world);

(2) Using the self-fertile dual-purpose GMS line N876S of the Rice Research Institute of Anhui Academy of Agricultural Sciences as the female parent (Guangzhan 63S as the female parent, crossed with Minghui 63, self-crossed after backcrossing (BC ₁ F ₃ ), obtained The two-line male sterile line of , which lasted 75-80 days since sowing) was crossed with Huang Huazhan to obtain a hybrid F ₁ (S). F ₂ (S) populations were generated by direct selfing of the hybrid F ₁ (S);

(3) Yangdao 6 was treated with 13np34, a material with golden shell and golden internodes obtained by mutagenesis from the Rice Research Institute of Anhui Academy of Agricultural Sciences (using 0.5% EMS (ethyl methylsulfonate), and the second generation of mutagenesis Obtain a stable line, the duration of sowing is about 100 days) as the female parent and cross with 14C195 to obtain a hybrid F ₁ (R), and directly self-seed the hybrid F ₁ (R) to generate an F ₂ (R) population;

(4) Hefei, sow and transplant F ₂ (S) and F ₂ (R) seeds (more than 2000 plants each) at the same time on May 5, and select two populations with similar initial earing stages on August 10-15 (sowing Individual plants with a difference of less than or equal to 2 days in the initial period) and excellent agronomic traits shall be marked. Perform microscopic examination on individual plants selected in the F ₂ (S) population, select individual plants without pollen, cut stubble, and transplant to another field for isolated planting to regenerate, and harvest mature seeds on the regenerated plants from individual plants; For individual plants selected in the F ₂ (R) population, seeds of individual plants are directly harvested when mature.

(5) In the same year, Hainan, on November 20-25, the individual plants selected by the two populations in step (4) were sown at the same time, and planted into adult rows (150-200 plants), and the selection of the initial earing period was similar (the sowing period A single plant with a difference of ≤2 days) and excellent agronomic properties should be harvested.

(6) Next year, in Hefei, sow on May 5-10, plant in rows (150-200 plants), and select individual plants with similar initial earing stages (difference between sowing and initial stages ≤ 2 days) and excellent agronomic properties. For the selected single plant of the F ₂ (S) offspring, microscopic examination of the pollen after the onset of panicle, the single plant without pollen was cut and transplanted to produce ratooning rice, and the seeds on the corresponding individual plant were harvested; for the single plant of the F ₂ (R) offspring , Harvest individual seeds directly after maturity.

(7) Step (5) and step (6) are repeated until the agronomic traits of the selected single plant are stable, and a sufficient number of seeds are collected.

(8) The seeds of F ₂ (S) and F ₂ (R) offspring harvested in step (7) were sown in stages in Hefei and Hainan respectively. The sowing dates in Hefei are 4/20, 4/30, 5/10, 5/20, 5/30, 6/9; the sowing dates in Hainan are 11/10, 11/20, 11/30, 12/10, 12/ 20, 12/30. In each sowing date, the lines with similar initial heading stages (difference between sowing and initial stages ≤ 2 days) were selected.

(9) With reference to the "Rice Light and Temperature Sensitive Male Genic Male Sterile Line Fertility Identification Regulations NY/T1215-2006NY/T1215-2006", the selected CMS line is subjected to fertility identification, and the CMS line that meets the standard is selected;

(10) take the sterile line selected in the step (9) as the female parent, test cross with the restorer line selected in the step (8), plant and observe the agronomic traits of the test cross F ₁ generation in Hefei (5-10 months), The F1 generation with excellent agronomic traits is selected, which is _a new hybrid rice variety with a similar growth period to the parents.

Breeding of comparative example hybrid rice

The hybrid rice male parent Huang Huazhan (the first sowing period is about 90 days in Hefei) and the female parent two-line GMS line N876S (Guangzhan 63 improved strain, the first sowing period is 75-80 days) were planted alternately. Sow the male parent with a long sowing period, and then sow the female parent with a short sowing period according to the difference in days between the male parent and the female parent, so that the male parent and the female parent can head, flower and bloom at the same time. Pollination, harvesting of seeds.

Comparison of Seed Production Efficiency in Experimental Example 1

The seed production efficiency of the hybrid rice combination bred in Example 1 of the present invention was compared with that of the control example, and the results are shown in Table 1.

Table 1 Comparison of Seed Production Efficiency

The results show that traditional hybrid rice breeding requires manual sowing and transplanting of the parents in stages due to the different sowing periods of the male parent and the female parent, which requires a large amount of labor and high cost. The risk of not meeting this flowering period is relatively large, and it is difficult to guarantee the yield of seed production.

However, the growth period of the parents of the hybrid rice combination of the present invention is similar (difference between the beginning and end of sowing≤2 days), mechanical mixed sowing does not need to transplant the parents, and realizes the mechanization of simultaneous sowing and production of the parents, with a small amount of labor and low cost. The seed production efficiency is high; moreover, the flowering period of the parents meets, which reduces the risk that the flowering period of the parents does not meet, and ensures the yield of hybrid rice seed production.

Claims (10)

1. a hybrid rice breeding method close to the beginning of sowing of a parent, is characterized in that, comprises the following steps: (1) Select a restorer line and a CMS line with a similar initial sowing period, and then use the CMS line as the female parent to testcross with the restorer line to obtain a testcross F ₁ generation; (2) Select a testcross F ₁ with excellent traits Generation, that is. 2. according to the hybrid rice breeding method described in claim 1, it is characterized in that: the breeding of the restorer line and the sterile line that the described sowing period of step (1) is similar, comprises: (1) Using the sterile line' as the female parent to cross with the rice parent to obtain the hybrid F ₁ generation; (2) using the sterile line '' described in step ( ₁ ) as the recurrent parent to backcross the hybrid F1 generation to obtain backcross offspring; self _- cross the backcross offspring to obtain BC _n F2 populations; (3) Using the restorer line' as the female parent to cross with the rice parent' to obtain the hybrid F ₁ 'generation; (4) Using the restorer line' described in step (3) as the recurrent parent to backcross with the hybrid F ₁ 'generation to obtain a backcross offspring'; self-cross the backcross offspring' to obtain a BC _n F ₂ 'population; (5) Sow the BC _n F ₂ population and the BC _n F ₂ ' population respectively, and self-cross for multiple generations until the traits are stable, and select and breed restorer lines and sterile lines with similar sowing start periods; or, (a) using the sterile line' as the female parent to cross with the rice parent to obtain the hybrid F ₁ generation; (b) selfing the hybrid F ₁ generation to generate F ₂ populations; (c) using the restorer line ' as the female parent to cross with the rice parent' to obtain the hybrid F ₁ 'generation; (d) selfing the hybrid F ₁ ' generation to generate F ₂ 'population; (e) Sow the F ₂ population and the F ₂ ' population separately, and self-cross for multiple generations until the traits are stable, and select and breed restorer lines and sterile lines with similar initial sowing periods. 3. according to the hybrid rice breeding method described in claim 2, it is characterized in that: the rice parent described in step (1) and the rice parent ' described in step (3) are similar in sowing period; The rice parent described in the step (a) and the rice parent ' described in the step (c) are close in duration. 4. The hybrid rice breeding method according to claim 1, 2 or 3, characterized in that: the sowing start dates are similar in that the sowing start dates differ by ≤ 2 days. 5. The hybrid rice breeding method according to claim 2, characterized in that: the backcrossing in step (2) or step (4) is backcrossing 1-3 generations; the selfing is selfing 1 time. 6. according to the hybrid rice breeding method described in claim 2, it is characterized in that, the described in step (5) sows respectively BC _n F ₂ population and BC _n F ₂ ' population, and continuous multiple generations of selfing until the character is stable, The selection and breeding of restorer lines and sterile lines with a similar initial sowing period includes the following steps: (I) Under the condition of high temperature and long day, sow and transplant BC _n F ₂ population and BC _n F ₂ ' population at the same time, select the individual plants with similar initial heading stage and excellent traits in the two populations, and harvest the seeds of candidate individual plants ; (II) In the same year, under low temperature and short-day conditions, simultaneously sowing and transplanting the seeds harvested by the two populations in the step (I) respectively, selecting a single plant with similar initial earing stage and good character, and harvesting the seeds; (Ⅲ) next year, under high temperature and long-day conditions, simultaneously sow and transplant the seeds harvested respectively in the step (II), select a single plant with similar initial earing stage and good character, and harvest the candidate single plant seeds; (Ⅳ) repeating step (II) and step (Ⅲ) until the selected individual plant traits are stable, harvesting seeds respectively; (Ⅴ) The seeds harvested in step (Ⅳ) are sown and transplanted in stages under high temperature, long-day conditions and low temperature, short-day conditions respectively, and the lines with similar initial earing stages are selected in each same sowing date, respectively. CMS and restorer lines; (Ⅵ) The sterile line selected in the step (Ⅴ) is subjected to the fertility identification, and it is obtained. 7. according to the hybrid rice breeding method described in claim 6, it is characterized in that, the described harvest candidate individual plant seed of step (I), comprises: selecting BC _n F ₂ in the population pollen sterile or no pollen individual plant, Cut the stubble, transplant it to make it regenerate, and harvest the seeds on the regenerated plants; directly harvest the seeds of the individual plants selected in the BC _n F ₂ 'population; Harvesting the seeds of candidate individual plants in step (Ⅲ) includes: selecting pollen-sterile or pollen-free individual plants for the selected individual plants of the progeny of the BC _n F ₂ population, cutting stubble, transplanting to produce ratooned rice, and harvesting the corresponding individual plants The seeds on the BC _n F ₂ 'population offspring, directly harvest the individual seeds; Preferably, wherein the cut stubble is rice stubble height 15-20cm; The sowing described in step (II) or step (III) is planting rows of adult plants. 8. according to the hybrid rice breeding method described in claim 2, it is characterized in that, (e) described sowing F ₂ populations and F ₂ ' populations respectively, and continuous multi-generational selfing until the character is stable, the breeding and sowing history Restorer lines and sterile lines with similar stages include the following steps: (I) Under high temperature and long _- day conditions, sowing and transplanting F2 population and F2' population at the same time, selecting individual plants with similar initial earing stages and excellent traits in the _two populations, and harvesting candidate individual plant seeds; (II) In the same year, under low temperature and short day conditions, simultaneously sow and transplant the seeds of the two populations harvested respectively in the step (I), select a single plant with similar initial earing stage and good character, and harvest the seeds; (Ⅲ) next year, under high temperature and long-day conditions, simultaneously sow and transplant the seeds harvested respectively in the step (II), select a single plant with similar initial earing stage and good character, and harvest the candidate single plant seeds; (Ⅳ) repeating step (II) and step (Ⅲ) until the selected individual plant traits are stable, harvesting seeds respectively; (Ⅴ) The seeds harvested in step (Ⅳ) are sown and transplanted in stages under high temperature, long-day conditions and low temperature, short-day conditions respectively, and select lines with similar initial earing stages in each same sowing date, respectively Selected sterile lines and restorer lines; (Ⅵ) The sterile line selected in the step (Ⅴ) is subjected to the fertility identification, and it is obtained. 9. according to the hybrid rice breeding method described in claim 8, it is characterized in that, the described harvest candidate individual plant seed of step (I ₎ , comprises: select the individual plant of pollen infertility or no pollen in F2 population, stubble cutting , and transplanted to make it regenerated, and the seeds on the regenerated plants are harvested from a single plant; for the selected individual plants in the F ₂ ' population, the seeds of a single plant are directly harvested; Harvesting the seeds of candidate individual plants as described in step (Ⅲ) includes: selecting pollen-sterile or pollen-free individual plants for the selected individual plants of the progeny of the F2 population, cutting stubble, transplanting to produce _ratooned rice, and harvesting the seeds on the corresponding individual plants. Seeds; for a single plant of the offspring of the F ₂ ' population, the single plant seed is directly harvested; Preferably, wherein the cut stubble is rice stubble height 15-20cm; The sowing described in step (II) or step (III) is planting rows of adult plants. 10. The method for breeding hybrid rice according to claim 6 or 8, characterized in that: the start of panicle period is similar to that of sowing start period with a difference of ≤ 2 days; The high temperature and long day conditions are April-October in Hefei, preferably May-October; the low temperature and short day conditions are November-December in Hainan; The staged sowing in step (Ⅴ) is sowing in 6 stages, and one stage is sown every 10 days; the transplanting is 30 days after sowing and transplanted at the same time.