CN114009286A - Cultivation method for maize hybrid seed production - Google Patents

Abstract

The invention provides a cultivation method for corn hybrid seed production, which comprises seed production base selection, isolation area arrangement, seeding, flowering prediction and regulation, roguing and roguing, female parent castration and pollination, male parent timely cutting and harvesting; according to the seed production and cultivation method, the 'seed gathering method' is adopted for the male parent planting in the production process, the labor force is saved, the occurrence of plant diseases and insect pests is greatly reduced, the problems of ventilation and light transmission are skillfully solved, the number of female parent plants is increased by 1200, the yield is increased, and the quality of corn hybrid seeds is improved; the purity of the hybrid seeds produced by the method is more than or equal to 98 percent, the purity is more than or equal to 99 percent, the germination percentage is more than or equal to 95 percent, and the water content is less than or equal to 13 percent, thereby meeting the first-grade seed quality standard specified by the national seed Law and leading the corn hybrid seed production technology to be more standardized, programmed and specialized.

Description

Cultivation method for maize hybrid seed production

Technical Field

The invention belongs to the technical field of plant cultivation, and particularly relates to a cultivation method for maize hybrid seed production.

Background

Corn is an important crop used for both food and feed in the world, corn is called pearl on imperial crown in the United states, and corn is called national treasure in France. China is the second country of world corn production, the annual sowing area is about 2400 hectares, the seed demand is more than 10-12 hundred million kilograms, which accounts for about 1/5 of the total area of the world, and the hybrid seed production area for sowing in the field is about 25 hectares. Corn is a crop used as both grain and feed, the development of corn production not only solves the problem of satiety of huge population, but also provides a material basis for the development of the global animal husbandry, greatly enriches the sources of concentrated feed and coarse feed which are wide in the development of the animal husbandry, the enriched concentrated feed and coarse feed are all necessary material raw materials for cattle, sheep, pigs, chickens, ducks and geese, and the corn plays a significant role in the grain safety and economic development of the world and even China. Production practices prove that the seeds always occupy the leading position in the corn production, the first filial generation seeds account for 25-30% of the factors of the corn yield increase, and the cultivation method of the first filial generation seeds of the corn is crucial to the corn production development, so that the cultivation method of the first filial generation seeds is the key point for ensuring the seed quality and reducing the production cost, and is also an important way for improving the seed yield.

Disclosure of Invention

The invention aims to provide a cultivation method for maize hybrid seed production, which reduces the production cost, increases the seed yield, improves the seed quality and meets the requirement of the first-level seed quality standard.

The technical scheme adopted by the invention is as follows: a cultivation method for maize hybrid seed production specifically comprises the following steps:

s1, seed production base selection:

the base is selected below the elevation of 1700 meters, the effective accumulated temperature of more than or equal to 10 ℃ is 3000-;

s2, setting an isolation region:

adopting any one or combination of space isolation which is not less than 300 meters away from other corn pollen sources, sowing time staggered isolation of the corn in the isolation area and the adjacent corn, natural barrier isolation or high-stalk crop isolation;

s3, sowing:

step 1, land preparation and fertilization: after harvesting previous crops, deeply ploughing and cleaning the stubbles in time, irrigating enough winter water, performing 12-16cm shallow ploughing on soil before film mulching and sowing, and cleaning field impurities; applying 3000-4000kg of high-quality farmyard manure per 667 square meters in combination with shallow ploughing as base fertilizer, and applying 20-25kg of diammonium phosphate as seed fertilizer, with the middle of the mulching film as a base line, and applying fertilizer at the depths of 15-20cm at two sides of the base line;

step 2, drawing lines and laminating: in the last ten days of 4 months, a marker is adopted to draw lines with the interval of 1m along straight ridges, the lines are straightly and uniformly moved, mulching films with the width of 70-80cm and the thickness of 0.005-0.008mm are adopted according to the lines, soil is covered at the positions of 5-10cm on two sides of the films, soil knots are tied at intervals of 2-3 m, the films are integrally connected to form a straight line, the two sides of the films are compacted, the film surface is kept at 50cm, the empty ditches are kept at 50cm, and the damages are found after the films are covered, and the pressure is timely supplemented;

and 3, determining the dosage of the parent seeds: selecting parent seeds with good coating, the purity of 98 percent and the germination rate of more than 95 percent, and checking the seeding quantity according to the thousand seed weight and the germination rate of the seeds before seeding;

step 4, reasonably close planting: single cross seed production, early maturing or compact selfing line, density is 5500 and 6500 plants per 667 square meters; three-way or double-way seed production, wherein the parent single-way seed is higher, and the density is 5000-6000 strains per 667 square meters; the plant height is high, the leaf angle is large, the plant spacing is 25-28 cm, 4500-5000 plants are protected per 667 square meters; the leaves are vertically and compactly combined, the plant spacing is 22-25 cm, and 5500 seedlings are protected per 667 square meters and 6000 plants are obtained;

and 5, sowing in a suitable period, reasonably configuring male parents: firstly sowing the female parent and the male parent in two stages, wherein the first stage and the second stage are separated by 5-7 days, a male parent row is not arranged in a field during sowing, the male parent is planted on a mulching film between the two rows of the female parent, and the plant spacing of the male parent is 2 times of that of the female parent; sowing the male parents in stages, sowing the male parents in a first stage in a pit of the male parents at a plant spacing of 80cm in the middle of a mulching film, sowing the male parents in a second stage at intervals of 5-7 days, sowing the male parents in the first stage in a pit of 4-6 seeds in the middle of two pits of the male parents, and covering soil and compacting the male parents after sowing the male parents in the first stage to ensure the seedlings;

s4, flowering phase prediction and regulation:

step 1, flowering phase prediction: adopting a standard leaf investigation method, a leaf stripping inspection method or a young ear differentiation inspection method to predict the flowering phase in the seedling stage;

(1) survey of labeled leaves: in a seed production field, selecting representative male parents and female parents at 3-5 points respectively according to the total number of leaves of parents, selecting 10 typical plants at each point, periodically marking leaves to investigate the number of leaves of the male parents and the female parents, performing leaf marking once every 5 leaves, and performing leaf marking 3 times in the whole growth period; predicting the growth speed and the meeting speed of parents according to the appearance of the leaves of the parents;

(2) leaf peeling inspection method: after the parents are subjected to jointing, selecting representative plants and stripping the number of the non-extracted leaves, and determining whether the florescence of the parents meet according to the number of the non-extracted leaves;

(3) young ear differentiation observation method: in the stage of jointing and booting, selecting representative sample points in a seed production field, taking 3-5 representative male parent plants and female parent plants at each point, stripping off leaves, checking the size of young spikes, and determining whether the two parents are in the same flowering phase;

step 2, regulating and controlling the flowering phase: adopting a seeding period adjusting method or a seedling period adjusting method;

(1) a sowing period adjusting method: adopting a male parent staged sowing method or determining a sowing method by using the growth period of the parents; the male parent stage sowing method comprises the following steps: sowing the first-stage male parents, reserving 10 holes every 10 holes, sowing the female parents and the second-stage male parents in the reserved holes every 7 days, wherein the first-stage male parents and the second-stage male parents respectively account for 50 percent to form second-stage male parents; the parent growth period determination seeding method comprises the following steps: the silking period of the female parent is 2-3 days earlier than the pollen scattering period of the male parent, and the male parent and the female parent sow in the same period; soaking the male parent in the same heading period for 8-12 days, and sowing the male parent in the same period as the male parent, or sowing the male parent in the late period for 3-4 days; the heading periods of the parents are different by more than 5 days, and the sowing period is adjusted;

(2) seedling stage regulation method: in the seedling stage, when the growth speeds of the male parent and the female parent are inconsistent, the growth of the male parent and the female parent is promoted slowly, and the growth of the male parent and the female parent is controlled quickly;

s5, castration and pollination of female parent:

step 1, removing the mixed seedlings: thoroughly removing field seedlings, weak seedlings and diseased seedlings before castration;

step 2, castration: by adopting a method of performing primary tasseling by touching and wrapping with leaves, when the tassels are big and the tassels are just exposed to the tips, 1-2 leaves or 3 leaves are taken out from the uppermost segment completely at one time without remaining broken branches or residual branches;

step 3, pollination: carrying out artificial supplementary pollination in the main pollen-scattering period of the male parent and the full silk-spitting period of the female parent, and continuously carrying out the pollination for 2-3 times in the full-bloom period;

s6, cutting off the male parent in time:

after the female parent pollination is finished, according to the characteristics of variety combination, all the male parents are cut off, and then the male parents are cleaned;

s7, harvesting:

and peeling the harvested fruit ears in time, airing, keeping the thickness of the harvested fruit ears to be less than 10cm, tedding once every 5-7 days, and removing filaments, bracts, miscellaneous ears, sick ears, the heritable male parent and severe ears bitten by rats in the tedding process.

Preferably, in S1, the crop of the first crop of the seed production field is the soil of wheat, barley, vegetables, beans, shallot or garlic.

Preferably, in S2, the space isolation distance is divided into natural isolation of 300-400 meters according to variety combination, terrain, wind direction and wind power.

Preferably, in S2, the sowing time of the corns and the adjacent corns in the isolation area is staggered for more than 40 days.

Preferably, in S3, mechanical precision seeding or manual dibbling seeding is adopted: at the position of the soil pressed on the membrane side and outside the lighting surface, a dibbler is used for breaking membranes, punching holes and dibbling, the sowing depth is 3-5cm, and the row spacing of female parents is 40-60 cm; after sowing, dibbling sorghum at the head of the male parent row to serve as a marked crop.

Preferably, in S3, sowing seeds when the temperature of soil with the thickness of 5-10cm in the plough layer of the spring sowing area is stabilized at 10-12 ℃; under the condition of film covering, the temperature of plough layer soil is stabilized at 8-10 ℃ for sowing; or sowing the seeds 10-25 days every 4 months according to the characteristics of the Hexi climate or the combination characteristics, delaying the sowing period along with the rise of the altitude, and determining the optimal sowing period according to different combinations of the staggered periods of the male parent and the female parent.

Preferably, in S5, emasculation needs to be timely, thorough and clean, and the quality standard reaches that the rate of female parent pollen scattering plants is lower than 0.1%.

Preferably, in S5, shaking plant pollination or pollen collection pollination is selected for artificial pollination; shaking and pollinating plants: pulling with rope or long rod to make male ear of male parent or shaking male parent plant with hand to promote pollen scattering to reach pollination, and continuously carrying out 2-3 times in the full bloom period with large pollen amount of male parent; pollen collection and pollination: collecting pollen, removing anther, placing in a bamboo tube filled with a small amount of cotton, covering the opening of the bamboo tube with gauze, aligning the opening with the filament, and tapping on the bamboo tube to make the pollen uniformly float on the filament.

Further, impurity removal and deterioration removal are carried out for five times in three periods of corn growth; the method specifically comprises the following steps:

(1) removing impurities before sowing: before sowing, sun-drying seeds, removing impurities, blighted grains and worm-eaten grains due to mildew in the seeds according to the color, size and grain type of the seeds;

(2) removing impurities in the field: dividing 3 times, combining thinning and final singling in the seedling stage for the 1 st time, removing impurities, inferior plants, diseased plants and seedlings according to the sheath color, the marginal color, the leaf shape, the leaf direction, the leaf color and the growth vigor of the parent leaves, keeping the sizes of the female parent seedlings consistent, and keeping double seedlings at the seedling lacking positions; the male parent seedlings are different in size to prolong the pollen scattering period; the 2 nd time is carried out in the jointing stage, impurities are removed according to plant height, leaf shape, leaf direction, leaf color, leaf margin and growth vigor, and suspicious plants are pulled out together with dominant plants; before 3 rd emasculation, impurities are removed according to plant types, leaf shapes, leaf directions, bracts and filament colors, the plants and double plants are thoroughly removed at one time, and the pollen of the mixed plants is prevented from diffusing and spreading in an isolation area; removing impurities from the male parent, and checking the male parent by plant according to the branch number and anther color of the male ear of the male parent; removing impurities of the female parent according to the color of filaments of the female ear;

(3) threshing and impurity removing after harvesting: ear selection is carried out on the male parent ears according to ear type, grain color and axial color shapes, ear impurities and inferior ears are removed, and threshing is carried out when the ear impurities rate is controlled to be below 1.5%.

Compared with the prior art, the invention has the beneficial effects that:

1. according to the seed production cultivation method, the method of 'gathering seeds' is adopted for planting by selecting male parents in the production process, so that seeds are saved, labor force is saved, ventilation and light transmission are skillfully solved, the number of female parent plants is increased to 1200, the seed yield is increased, and the quality of corn hybrid seeds is improved.

2. According to the invention, the corn seed production male parent planting is carried out through the 'seed gathering method', so that a large number of male parent seeds are saved, the labor force consumed by manual castration in a seed production field is reduced, the labor cost is saved by 300 yuan per mu, the environment of ventilation and light transmission in the field is solved, 667 square meters in the field and the number of female parent plants are increased, and the yield of the corn seed production in unit area is effectively improved.

Detailed Description

The invention will be further explained and illustrated with reference to specific examples;

a cultivation method for maize hybrid seed production specifically comprises the following steps:

selection of seed production base

The principle of isolation, safety, relative concentration, continuous planting, impurity prevention and purity preservation is adopted in the selected corn seed production base;

1. the production area environment: the base is selected below the elevation of 1700 meters, the effective accumulated temperature of more than or equal to 10 ℃ is 3000-; the frost-free period is over 135-140 days, the isolation condition is good, the land is flat, fertile and convenient to irrigate, no pollution is caused, and the areas are concentrated.

2. Soil conditions: selecting a loam land with deep soil layer, fertile soil and convenient irrigation and drainage, requiring few or no trees in the field, and being not suitable for being planted in continuous cropping land, saline-alkali land, sand leakage land, garden land and tuyere sand land for more than two years.

3. The crop rotation requirement is as follows: according to the species of the crops in the riverside corridor, in order to ensure the high quality and the high yield of the produced seeds, the crops in the first crop of the seed production field are preferably wheat, barley, vegetables, beans, green onion, garlic, green manure and the like.

Secondly, setting an isolation region

1. Space isolation: the 'seed gathering method' is a main isolation method for configuring corn hybrid seeds; the same kind of crops (other corns) are not planted in a certain space range around the isolation area; the isolation distance can be divided into 300-400-meter natural isolation according to variety combination, terrain, wind direction and wind power, and the distance from other corn pollen sources is guaranteed to be not less than 300 meters.

2. Time isolation: the sowing time of the corns and the adjacent corns in the isolation area are staggered, so that the flowering time of the corns and the adjacent corns is staggered, and the purpose of isolation is achieved in terms of time; attention should be paid to the collocation of early, middle and late maturing varieties; when the time isolation is adopted in the Hexi spring sowing and seed production area, the wrong period is more than 40 days.

3. Isolation by a natural barrier: according to local conditions, natural barriers such as mountains, villages, forest belts and orchards are utilized to prevent introduction of external pollen, and natural barriers such as villages (which are continuous and integrated) and large-scale forests with the length of not less than 200 m are adopted for isolation.

4. Isolating high-stem crops: when space isolation cannot be guaranteed and no natural barrier exists, high-stalk crops such as sorghum, ambary, sunflower and the like can be planted around the isolation area for isolation; the row number of the high-stem crops is not too small, the width of the high-stem crops to be planted in the inbred line breeding area is more than 200 meters, and the seed production area is more than 100 meters; the high-stalk crops are sowed early and managed intensively to ensure that the height of the high-stalk crops is obviously higher than 60-70 cm of the seed corn during the corn emasculation.

In order to facilitate the arrangement of the isolation regions, the above isolation methods can be adopted at the same time around one isolation region.

Third, sowing specification and method

1. Land preparation and fertilization: after harvesting crops in autumn in the last year, deeply ploughing and cleaning stubbles in time, irrigating enough winter water, performing shallow ploughing on soil before film mulching and sowing, wherein the depth is about 15cm, and cleaning residual broken mulching films and corn roots in the field; spraying a pesticide 'glyphosate' on the hay on the ridges to play a role in killing plant diseases and insect pests; applying 3000-4000kg of high-quality farmyard manure per 667 square meters in combination with shallow ploughing as base fertilizer, and 20-25kg of diammonium phosphate as seed fertilizer, taking the middle of the mulching film as a base line, and applying fertilizer at the depths of 15-20cm on two sides of the base line to avoid burning seeds due to contact of the seed fertilizer and the seeds; 0.5-1 kg of zinc sulfate is applied to 667 square meters of soil with zinc deficiency; treating medicament soil of corn fields continuously planted for years, such as selecting and using bactericides such as thiophanate methyl, rickettsia, carbendazim and the like to prevent corn diseases; after ploughing, the land leveller is raked, pressed and preserved soil moisture in good time, and the land leveller can achieve soil moisture and soil moisture sufficiency without stubbles, residual films and deficiency and excess on the upper part.

2. Drawing lines and coating films: in the last ten days of 4 months, lines with the distance of 1 meter are drawn on the corn seed production field by a marker, the lines are required to be drawn along straight ridges to be straight and uniform, and then mulching films with the width of 70-80cm and the thickness of 0.005-0.008mm are adopted according to the lines; when the film is laid, the film surface is tightened and straightened, the two sides of the film are covered with soil at the positions of 5-10cm, soil knots are tied at intervals of 2-3 m, the whole film is connected into a straight line, the two sides of the film are compacted to prevent soil moisture from escaping and uncovering the film by strong wind, the film surface is kept at 50cm and the empty ditch is kept at 50cm, and the damage is found after the film is covered, and the pressure is timely supplemented.

3. Determining the dosage of parent seeds: the seed production parent selects seeds with the purity of 98 percent and the germination rate of more than 95 percent; before sowing, the sowing quantity is verified according to the thousand seed weight and the germination rate of the seeds, and the selected and coated parent seeds are distributed to hands of a seed production user, wherein generally, 3-4 kg of female parent per 667 square meters and 0.6-1.0 kg of male parent per 667 square meters.

4. Reasonably close planting: the planting density depends on the parent species of the variety combination, plant type, cultivation level, soil fertility and other factors, and generally follows the following principle: single cross seed production, early maturing or compact selfing; generally, the density is 5500-6500 strains per 667 square meters, the seeds are bred by three-way cross or double-way cross, the parent single-way cross is higher, and the density is 5000-6000 strains per 667 square meters; the combination is different, the plant spacing is different, the plant height and the leaf angle are large, the plant spacing is 25-28 cm, and 4500-5000 seedlings are protected per 667 square meters; the blades are vertically and compactly combined, the plant spacing is 22-25 cm, and 5500 seedlings are protected and 6000 plants are protected per 667 square meters.

5. Sowing in a proper period, reasonably configuring a male parent: the proper sowing period is that the temperature of soil with 5-10cm thickness in the plough layer of the spring sowing area is stabilized at 10-12 ℃; under the condition of film covering, the soil temperature of the plough layer is stabilized at 8-10 ℃ for sowing; according to the characteristics or the combination characteristics of the climate in Hexi, sowing is generally carried out for 10-25 days in 4 months each year, the sowing period is properly delayed along with the rise of the altitude, and the optimal sowing period is determined by different combinations of the wrong period of the parents;

the method comprises the steps of sowing female parents and male parents in two stages, wherein the first stage and the second stage are separated by 5-7 days, the traditional male parent planting modes comprise a row ratio planting method, a row ratio and gypsophila mixed planting method and a gypsophila planting method, and the three types have overlarge density in different degrees, too many male parents are planted, labor and time are wasted, the disease breeding is caused by shade and canopy closure, the seed production yield is reduced, and the target of ideal seed production yield cannot be achieved; the invention adopts a 'seed gathering method' to plant male parents, and specifically comprises the following steps: the field is not provided with a father line, the male parent is planted on the mulching film between two lines of female parents, and the plant spacing of the male parent is 2 times of that of the female parents; sowing stage by stage, sowing male parents in the middle of the mulching film at a first stage in a pit with a plant spacing of 80cm, sowing the male parents at a second stage at intervals of 5-7 days in a field with one bunch, sowing the male parents at the first stage in a pit with 4-6 granules in the middle of two pits of the male parents at the first stage, and covering soil and compacting after sowing the male parents at each time to ensure the seedlings.

The planting mode of the invention adopts a single mode (one field can not be planted with other crops). The invention adopts a 'seed gathering method' to plant the male parents, thereby not only improving the seed production yield and saving the labor force, but also greatly reducing the occurrence of plant diseases and insect pests, and the seed purity is 98 percent, the purity is 99 percent, the germination rate is 95 percent, the water content is 13 percent, and the quality reaches the first-level standard issued by 'seed law'.

The seeding can adopt mechanical precision seeding or manual dibbling, and a dibbler is used for breaking a membrane, punching holes and dibbling the holes at the position (the outer side of a lighting surface) where the soil is pressed at the membrane side. According to the characteristic of the variety, the line spacing of the female parent is controlled to be 40-60cm (60 cm wide lines, 40 cm narrow lines and 50cm equal line spacing); if dry land with winter irrigation and spring irrigation does not exist and sandy soil with poor soil moisture content, film breaking and dibbling can be performed, sand is covered, shallow irrigation is performed, and water is set for dibbling; after sowing, dibbling sorghum at the head of a male parent row to serve as a marked crop; the sowing depth is 3-5cm, which is determined according to the climatic characteristics of each seed production point and the soil moisture content.

Fourthly, flowering phase prediction and regulation

1. And (3) flowering phase prediction: adopting a standard leaf investigation method, a leaf stripping inspection method or a young ear differentiation inspection method;

(1) survey of labeled leaves: in a seed production field, selecting representative male parents and female parents at 3-5 points respectively according to the total leaf number of parents, selecting 10 typical plants at each point, periodically marking leaves to investigate the leaf number of the male parents and the female parents, performing leaf marking once every 5 leaves, and performing leaf marking 3 times in the whole growth period; according to the appearance of the leaves of the parents, the development speed of the parents is predicted, and if the number of the leaves of the female parent is 1.5-2 more than that of the male parent, the parents can meet well.

(2) Leaf peeling inspection method: after the parents are subjected to jointing, selecting representative plants and stripping the number of the non-extracted leaves, and determining whether the florescence of the parents meet according to the number of the non-extracted leaves; if the female parent has 1.5-2 less leaves than the male parent, the flower-season meeting is good; if more than 2 sheets or less than 1.5 sheets are used, there is a possibility that the poor meeting will be caused, and the inspection accuracy is high in the case of a large flare.

(3) Young ear differentiation observation method: and (3) in the stage of jointing and booting, selecting representative sample points in a seed production field, taking 3-5 representative male and female parent plants at each point, stripping leaves, checking the size of young ears, and if the differentiation of the young ears of the female parent is earlier than that of the male parent by one period, indicating that the flower phases meet well, otherwise, the young ears are probably not met.

2. And (3) flowering phase regulation: the invention adopts a seeding stage adjusting method or a seedling stage adjusting method;

the regulation principle is as follows: firstly, arranging the female parent in the optimum sowing period, and then adjusting the sowing period of the male parent; secondly, the principle of 'mother-equal father, father-mother-in-mother' is adhered to, according to the climate characteristics of local perennial, and by combining weather prediction of the current year, the optimal sowing period is reversely deduced under the condition of determining the optimal pollination period of the current year, namely the 'mother-equal father', namely the mother-equal father prefers to spin the pollen of the father before the pollen of the father for 2-3 days, and the pollination period avoids the unfavorable periods of high temperature, drought and the like. The 'parent-mother' is to have a longer blooming period to cover the blooming period of the parent, so that the 'head flower is not empty, the head flower is impacted in the main period, and the tail flower is useful', namely the blooming period of the parent (60% of plants bloom) and the main blooming period of the parent (60% of plants bloom) occur in the same day, and the blooming period of the parent and the parent meet each other.

(1) A sowing period adjusting method: adopting male parent stage sowing method or using parent growth period to determine sowing period;

the male parent stage sowing method comprises the following steps: according to the characteristics of the male parent and the female parent, in order to ensure that the flowering phases of the male parent and the female parent meet and prolong the pollen dispersion of the male parent, the male parent in the first period is sown firstly (10 holes are reserved every sowing 10 holes), the female parent and the male parent in the second period are sown every 7 days (sowing in reserved holes), and the male parents in the first period and the male parent in the second period respectively account for 50 percent to form the male parent in the second period, so that the pollen dispersion phase of the male parent is prolonged, the problem of flowering asynchronism is solved, and the pollination rate are improved.

Determining the sowing time by using the growth period of parents: if the silking period of the female parent is 2-3 days earlier than the pollen scattering period of the male parent, sowing the male parent and the female parent at the same time; if the heading period of the parents is the same, soaking the male parent for 8-12 days, and sowing the male parent in the same period or sowing the male parent for 3-4 days later; if the heading periods of the parents are different by more than 5 days, the sowing period is adjusted.

(2) Seedling stage regulation method: whether the parent and the female parent of the seed field meet in the flowering phase or not, early prediction and early regulation are needed in the seedling phase, and the flowering phase is guaranteed to be lost; when the growth speeds of the parent and the female parent are inconsistent, a 'speed-promoting and speed-controlling method' can be adopted to carry out early seedling thinning, early thinning and large seedling remaining, proper thinning and early fertilizing and early loosening on the parent and the female parent, improve the ground temperature and promote the growth of the parent and the female parent; for the parent with fast growth, the seedling may be thinned, the seedling may be left, fertilized and loosened to control its growth.

Fifth, impurity removal and roguing

Five times in three stages of corn growth;

1. removing impurities before sowing: before sowing, sun-drying seeds are combined, and impurities, blighted grains and worm-eaten grains of mildew in the seeds are removed according to the color, the size, the grain type and the like of the seeds.

2. Removing impurities in the field: dividing into 3 times, combining thinning and final singling in the seedling stage for the 1 st time, removing impurities, inferior plants, diseased plants and plants according to the sheath color, the marginal color, the leaf shape, the leaf direction, the leaf color, the growth vigor and the like of the parent leaves, keeping the size of the female parent seedlings consistent, and keeping double seedlings at the seedling lacking positions; the male parent seedlings are different in size to prolong the pollen scattering period; the 2 nd time is carried out in the jointing stage, impurities are removed according to plant height, leaf shape, leaf direction, leaf color, leaf margin, growth vigor and the like, and suspicious plants are pulled out together with dominant plants; before 3 rd emasculation, impurities are removed according to plant types, leaf shapes, leaf directions, bracts and filament colors, the impurities are thoroughly removed at one time, and three types of plants (namely dwarf plants, diseased inferior plants and abnormal plants) and two plants ensure that pollen of the hybrid plants is absolutely not diffused and spread in an isolation area; removing impurities from the male parent, and checking the male parent by plant according to the branch number and anther color of the male ear of the male parent, wherein the removed impurities cannot only cut the top of the male ear and leave half of the male ear; the female parent is subjected to impurity removal according to the color of filaments of the female ear; all the mixed plants must be uprooted.

3. Threshing and impurity removing after harvesting: and (4) carefully selecting the male parent ears according to the shapes of ear types, grain colors, axial colors and the like, and removing the impure ears and the inferior ears. When the ear-mixing rate is below 1.5%, the threshing can be carried out.

Sixthly, castration and pollination of female parent

In the production of corn hybrid seeds, thorough and clean emasculation of female parents is the key for ensuring the purity of the seeds and improving the quality of the seeds:

1. removing seedlings: thoroughly removing field seedlings, weak seedlings and diseased seedlings before castration;

2. castration: emasculation needs to be timely, thorough and clean, the quality standard reaches that the pollen dispersing rate of the female parent is lower than 0.1%, and the female parent within 3 m around the pollen dispersing plant is completely cut off or tassel is removed when the pollen dispersing plant appears; the method of once emasculation with leaves can be adopted, when the tassel is big in the belly to the point of the tassel just bared (the female parent silks do not show the head), 1-2 leaves or 3 leaves are taken out from the uppermost segment thoroughly at one time, and no broken branches or residual branches are left; the operation method of one person standing in one ditch to draw one line (gather) during castration is carried out no matter the size of the plant is carried out one by one, so that the problems of heavy drawing and no leakage of drawing are solved, and the purposes of saving labor and improving working efficiency are achieved.

3. Pollination: in the pollination period of the corn, when the flowering period is inconsistent due to factors such as cultivation management errors or irresistible natural disasters (such as high temperature, hail disasters, diseases and disasters, flood disasters) and the like, artificial auxiliary pollination can be carried out in the main pollen-scattering period (60 percent pollen-scattering of the male parent) of the male parent and the full silking period (60 percent silk-spraying of the female parent) of the female parent, and the artificial auxiliary pollination is continuously carried out for 2-3 times in the full-flowering period;

the artificial pollination comprises the following two methods:

(1) shaking and pollinating plants: continuously carrying out the pollination for 2-3 times in the full bloom period with larger pollen amount of the male parent, preferably carrying out the pollination at 9-11 am, and using rope pull or long rods to dial male ears of the male parent or shaking the male parent plant by hands to promote pollen scattering to achieve the aim of pollination.

(2) Pollen collection and pollination: the pollen distribution method comprises collecting pollen after dew is dried in the morning on a fine day, removing anthers with a fine basket, placing into a bamboo tube filled with a small amount of new cotton, covering the opening of the bamboo tube with gauze, aligning the opening with the filament, holding a small stick with one hand, and lightly tapping on the female ear to make the pollen uniformly float on the filament; the pollination time is preferably 9-11 am. Fresh pollen is used for pollination. When pollination is affected by high temperature and dryness, water can be timely poured to promote pollen scattering of male flowers. The pollination effect is prevented from being influenced by accelerated pollen death caused by accumulation of pollen due to overlarge pollen collection amount.

Seven, timely cutting off male parent

After pollination of the female parent is finished, according to the characteristics of variety combination, the male parent is required to be completely cut off before 8 months and 10 days in a spring sowing and seed production area in Hexi region, a seed production field is cleaned, the ventilation and light transmission conditions in the field are improved, the nutrient consumption and the occurrence of plant diseases and insect pests are reduced, the growth and development of the female parent are promoted, the dehydration of the seed is accelerated, the seed is matured in advance, the thousand seed weight of the female parent is improved, the color of the seed is improved, the commodity and the yield of the seed are improved, and the yield can be improved by about 8% compared with the yield of the male parent which is not cut off.

Eighthly, harvesting

Harvesting in Hexi area at 15-20 days after 9 months, and timely peeling and drying all harvested clusters before 1 day after 10 months; and (3) airing the peeled fruit clusters to a place with sufficient sunlight, wherein the airing thickness is not more than 10cm, the fruit clusters are aired once every 5-7 days, and all the filaments, the bracts, the miscellaneous ears, the sick ears, the heritable male parents and the ears seriously bitten by the rats are completely removed in the process of airing.

Comparing the yield of the first filial generation seeds with that of the common seeds under the same water and fertilizer conditions, as shown in Table 1;

TABLE 1 comparison of the yield per 667 sq.m of seeds of first filial generation and general seeds under the same water and fertilizer conditions

The comparison test for 6 years proves that the yield increasing proportion of the hybrid seeds is 50.8 percent compared with the common seeds under the same water and fertilizer conditions. Meets the sampling results of grain farmers in the United nations in advanced agriculture, and meets the scientific data that the yield increase proportion of fine varieties in agricultural production (grain) is about 49 percent.

TABLE 2 comparison of the accumulated temperature of each seed production area and the yield per 667 square meters of the seed production method

The comparison of the seed production method and the yield of the corn for more than 30 years shows that: the first generation of corn hybrid seeds produced by the ' seed gathering method ', also called ' babysbreath ', meet the first-level seed quality standard of ' the seed Law of the people's republic of China ': namely, the purity is 98 percent, the purity is 99 percent, the germination percentage is 98 percent and the water content is 13 percent. The number of female parent plants is increased by 1200 plants per 667 square meters by the 'seed gathering method', the yield per mu is 1200 jin, the yield is increased by 35 percent compared with the conventional method by a row ratio method, and the yield is reduced by 28 percent compared with the method by planting male parent plants mixed with gypsophila by the row ratio method. The yield per mu of the 'seed gathering method' is 2400 yuan, the economic income is increased by 840 yuan compared with a row comparison method, and the income is increased by 1840 yuan compared with a row comparison method and a gypsophila mixed planting male parent. Meanwhile, compared with a comparison method, the 'seed gathering method' of the invention saves labor force and reduces economic investment.

Claims (9)

1. A cultivation method for maize hybrid seed production is characterized in that: the method specifically comprises the following steps:

s1, seed production base selection:

the base is selected below the elevation of 1700 meters, the effective accumulated temperature of more than or equal to 10 ℃ is 3000-;

s2, setting an isolation region:

adopting any one or combination of space isolation which is not less than 300 meters away from other corn pollen sources, sowing time staggered isolation of the corn in the isolation area and the adjacent corn, natural barrier isolation or high-stalk crop isolation;

s3, sowing:

step 1, land preparation and fertilization: after harvesting previous crops, deeply ploughing and cleaning the stubbles in time, irrigating enough winter water, performing 12-16cm shallow ploughing on soil before film mulching and sowing, and cleaning field impurities; applying 3000-4000kg of high-quality farmyard manure per 667 square meters in combination with shallow ploughing as base fertilizer, and applying 20-25kg of diammonium phosphate as seed fertilizer, with the middle of the mulching film as a base line, and applying fertilizer at the depths of 15-20cm at two sides of the base line;

step 2, drawing lines and laminating: in the last ten days of 4 months, a marker is adopted to draw lines with the interval of 1m along straight ridges, the lines are straightly and uniformly moved, mulching films with the width of 70-80cm and the thickness of 0.005-0.008mm are adopted according to the lines, soil is covered at the positions of 5-10cm on two sides of the films, soil knots are tied at intervals of 2-3 m, the films are integrally connected to form a straight line, the two sides of the films are compacted, the film surface is kept at 50cm, the empty ditches are kept at 50cm, and the damages are found after the films are covered, and the pressure is timely supplemented;

and 3, determining the dosage of the parent seeds: selecting parent seeds with good coating, the purity of 98 percent and the germination rate of more than 95 percent, and checking the seeding quantity according to the thousand seed weight and the germination rate of the seeds before seeding;

step 4, reasonably close planting: single cross seed production, early maturing or compact selfing line, density is 5500 and 6500 plants per 667 square meters; three-way or double-way seed production, wherein the parent single-way seed is higher, and the density is 5000-6000 strains per 667 square meters; the plant height is high, the leaf angle is large, the plant spacing is 25-28 cm, 4500-5000 plants are protected per 667 square meters; the leaves are vertically and compactly combined, the plant spacing is 22-25 cm, and 5500 seedlings are protected per 667 square meters and 6000 plants are obtained;

and 5, sowing in a suitable period, reasonably configuring male parents: firstly sowing the female parent and the male parent in two stages, wherein the first stage and the second stage are separated by 5-7 days, a male parent row is not arranged in a field during sowing, the male parent is planted on a mulching film between the two rows of the female parent, and the plant spacing of the male parent is 2 times of that of the female parent; sowing the male parents in stages, sowing the male parents in a first stage in a pit of the male parents at a plant spacing of 80cm in the middle of a mulching film, sowing the male parents in a second stage at intervals of 5-7 days, sowing the male parents in the first stage in a pit of 4-6 seeds in the middle of two pits of the male parents, and covering soil and compacting the male parents after sowing the male parents in the first stage to ensure the seedlings;

s4, flowering phase prediction and regulation:

step 1, flowering phase prediction: adopting a standard leaf investigation method, a leaf stripping inspection method or a young ear differentiation inspection method to predict the flowering phase in the seedling stage;

(1) survey of labeled leaves: in a seed production field, selecting representative male parents and female parents at 3-5 points respectively according to the total number of leaves of parents, selecting 10 typical plants at each point, periodically marking leaves to investigate the number of leaves of the male parents and the female parents, performing leaf marking once every 5 leaves, and performing leaf marking 3 times in the whole growth period; predicting the growth speed and the meeting speed of parents according to the appearance of the leaves of the parents;

(2) leaf peeling inspection method: after the parents are subjected to jointing, selecting representative plants and stripping the number of the non-extracted leaves, and determining whether the florescence of the parents meet according to the number of the non-extracted leaves;

(3) young ear differentiation observation method: in the stage of jointing and booting, selecting representative sample points in a seed production field, taking 3-5 representative male parent plants and female parent plants at each point, stripping off leaves, checking the size of young spikes, and determining whether the two parents are in the same flowering phase;

step 2, regulating and controlling the flowering phase: adopting a seeding period adjusting method or a seedling period adjusting method;

(1) a sowing period adjusting method: adopting a male parent staged sowing method or determining a sowing method by using the growth period of the parents; the male parent stage sowing method comprises the following steps: sowing the first-stage male parents, reserving 10 holes every 10 holes, sowing the female parents and the second-stage male parents in the reserved holes every 7 days, wherein the first-stage male parents and the second-stage male parents respectively account for 50 percent to form second-stage male parents; the parent growth period determination seeding method comprises the following steps: the silking period of the female parent is 2-3 days earlier than the pollen scattering period of the male parent, and the male parent and the female parent sow in the same period; soaking the male parent in the same heading period for 8-12 days, and sowing the male parent in the same period as the male parent, or sowing the male parent in the late period for 3-4 days; the heading periods of the parents are different by more than 5 days, and the sowing period is adjusted;

(2) seedling stage regulation method: in the seedling stage, when the growth speeds of the male parent and the female parent are inconsistent, the growth of the male parent and the female parent is promoted slowly, and the growth of the male parent and the female parent is controlled quickly;

s5, castration and pollination of female parent:

step 1, removing the mixed seedlings: thoroughly removing field seedlings, weak seedlings and diseased seedlings before castration;

step 2, castration: by adopting a method of performing primary tasseling by touching and wrapping with leaves, when the tassels are big and the tassels are just exposed to the tips, 1-2 leaves or 3 leaves are taken out from the uppermost segment completely at one time without remaining broken branches or residual branches;

step 3, pollination: carrying out artificial supplementary pollination in the main pollen-scattering period of the male parent and the full silk-spitting period of the female parent, and continuously carrying out the pollination for 2-3 times in the full-bloom period;

s6, cutting off the male parent in time:

after the female parent pollination is finished, according to the characteristics of variety combination, all the male parents are cut off, and then the male parents are cleaned;

s7, harvesting:

and peeling the harvested fruit ears in time, airing, keeping the thickness of the harvested fruit ears to be less than 10cm, tedding once every 5-7 days, and removing filaments, bracts, miscellaneous ears, sick ears, the heritable male parent and severe ears bitten by rats in the tedding process.

2. The method for breeding hybrid seeds of maize according to claim 1, characterized in that: in S1, the first crop in the seed production field is the soil of wheat, barley, vegetables, beans, shallot or garlic.

3. The method for breeding hybrid seeds of maize according to claim 1 or 2, characterized in that: in S2, the space isolation distance is divided into natural isolation of 300-400 meters according to variety combination, terrain, wind direction and wind power.

4. The method for breeding hybrid seeds of maize according to claim 3, characterized in that: in S2, the sowing time of the corns and the adjacent corns in the isolation area is staggered for more than 40 days.

5. The method for breeding hybrid seeds of maize according to claim 4, characterized in that: s3, sowing seeds when the temperature of soil with the thickness of 5-10cm in the plough layer of the spring sowing area is stabilized at 10-12 ℃; under the condition of film covering, the temperature of plough layer soil is stabilized at 8-10 ℃ for sowing; or sowing the seeds 10-25 days every 4 months according to the characteristics of the Hexi climate or the combination characteristics, delaying the sowing period along with the rise of the altitude, and determining the sowing period according to different combinations of the staggered periods of the male parent and the female parent.

6. The method for breeding hybrid seeds of maize according to claim 1, 2, 4 or 5, characterized in that: in S3, mechanical precision seeding or manual dibbling seeding is adopted: at the position of the soil pressed on the membrane side and outside the lighting surface, a dibbler is used for breaking membranes, punching holes and dibbling, the sowing depth is 3-5cm, and the row spacing of female parents is 40-60 cm; after sowing, dibbling sorghum at the head of the male parent row to serve as a marked crop.

7. The method for breeding hybrid seeds of maize according to claim 6, characterized in that: in S5, emasculation needs to be timely, thorough and clean, and the quality standard reaches that the rate of female parent scattered powder plants is lower than 0.1%.

8. The method for breeding hybrid seeds of maize according to claim 1, 2, 4, 5 or 7, characterized in that: in S5, artificial pollination is performed by shaking plant pollination or pollen collection pollination; shaking and pollinating plants: pulling with rope or long rod to make male ear of male parent or shaking male parent plant with hand to promote pollen scattering to reach pollination, and continuously carrying out 2-3 times in the full bloom period with large pollen amount of male parent; pollen collection and pollination: collecting pollen, removing anther, placing in a bamboo tube filled with a small amount of cotton, covering the opening of the bamboo tube with gauze, aligning the opening with the filament, and tapping on the bamboo tube to make the pollen uniformly float on the filament.

9. The method for breeding hybrid seeds of maize according to claim 8, characterized in that: also comprises roguing and roguing, which are carried out five times in three periods of corn growth; the method specifically comprises the following steps:

(1) removing impurities before sowing: before sowing, sun-drying seeds, removing impurities, blighted grains and worm-eaten grains due to mildew in the seeds according to the color, size and grain type of the seeds;

(2) removing impurities in the field: dividing 3 times, combining thinning and final singling in the seedling stage for the 1 st time, removing impurities, inferior plants, diseased plants and seedlings according to the sheath color, the marginal color, the leaf shape, the leaf direction, the leaf color and the growth vigor of the parent leaves, keeping the sizes of the female parent seedlings consistent, and keeping double seedlings at the seedling lacking positions; the male parent seedlings are different in size to prolong the pollen scattering period; the 2 nd time is carried out in the jointing stage, impurities are removed according to plant height, leaf shape, leaf direction, leaf color, leaf margin and growth vigor, and suspicious plants are pulled out together with dominant plants; before 3 rd emasculation, impurities are removed according to plant types, leaf shapes, leaf directions, bracts and filament colors, the plants and double plants are thoroughly removed at one time, and the pollen of the mixed plants is prevented from diffusing and spreading in an isolation area; removing impurities from the male parent, and checking the male parent by plant according to the branch number and anther color of the male ear of the male parent; removing impurities of the female parent according to the color of filaments of the female ear;

(3) threshing and impurity removing after harvesting: ear selection is carried out on the male parent ears according to ear type, grain color and axial color shapes, ear impurities and inferior ears are removed, and threshing is carried out when the ear impurities rate is controlled to be below 1.5%.