Maize three line seed production process, maize breeding method steps

The so-called three systems are:

1) Male sterile lines: Represented by the symbol (S) RFRF. (S) refers to sterility, which in parentheses indicates a genetic factor in the cytoplasm, and RF (Restere Fertile) refers to a pair of alleles in the nucleus that can restore male sterility.

2) Retention system: represented by the symbol (n) RFRF. The absence of male sterility factors in the cytoplasm of this strain is normal, so it is denoted by (n) (normal).

Whereas, RF in the nucleus is recessive and cannot restore the plant to fertile. When it is crossed as a paternal parent and sterile line, the panicle on the male sterile plant is still male sterile, so it is called the maintenance line. In order to make the plant fully pollinated and the convenience of collection, the male sterile line and the maintenance line are planted in a region, arranged in rows and rows, so that they can fully get the opportunity to cross, the pollen on the male sterile plant is not functional, so the panicle of the axillary knot must be a hybrid offspring, it is still a male sterile line, and the maintenance line can only rely on self-pollination to produce offspring, so the spikes of this system are still the maintenance line, so that a district in the "three lines and two areas" is formed.

This method not only enables the characteristics of sterile lines and maintainer lines to be stably inherited, solves the problem of male sterility and passage, but also allows the excellent traits controlled by the maintenance nucleus genes to be passed on to the male sterile offspring through multiple crosses, so that the sterile lines with certain excellent traits can be used as the maternal parent in cross breeding.

3) Restorer line: (N) RFF, this strain not only has no male sterility factor in the cytoplasm, but also has the gene RF in the nucleus to restore fertility, RF is dominant to RF, when the restorer line and the sterile line are crossed, the offspring produced although there are sterility factors in the cytoplasm, but the RF gene in the nucleus can inhibit its effect, so that heterozygous male fertile seeds can be produced

S) RFRF (N) RFRF (S) RFRF (male fertile).

In breeding, the restorer line and the sterile line that already have a certain excellent trait are planted in the middle one area, and arranged in rows, so that the ears of corn in the row of sterile lines are the hybrid seeds we need.

Like rice, but since the outbreak of corn spot disease in the United States, corn hybrid seed production basically does not use three lines, but artificial emasculation, sterile line maintenance line and recovery line.

Rice has sterile lines, maintenance lines, and restorer lines, and I haven't heard that there are three lines of corn for the time being.

There are also two lines of rice, light and temperature sensitive sterile lines.

Summary. Dear, I'm honored to have your question The information I found for you is: the difference between seed corn and conventional corn The difference between seed corn and conventional corn is mainly the difference in the output value of the two.

Under the same conditions, the output value of seed corn is much higher than that of conventional corn. This is mainly because the production of corn has a high scientific and technological content, whether it is cultivation, propagation and promotion, it requires many scientific experiments, consuming a certain amount of manpower and financial resources, so its commercial value is also very high. Generally speaking, the ** of seed corn is several times higher than that of conventional corn.

Seed corn is definitely different from ordinary corn, because seed corn is scientifically cultivated by experts, and ordinary corn has no reproductive ability.

The difference between seed corn and conventional corn.

What is the effect of even rain on seed corn? Which diseases have a greater impact on the planting process of seed maize? How to prevent it?

Which pests have a greater impact on the planting process of seed corn and how to prevent and control them?

Dear, I'm honored to have your question The information I found for you is: the difference between seed corn and conventional corn The difference between seed corn and conventional corn is mainly the difference in the output value of the two. Under the same conditions, the output value of seed corn is much higher than that of conventional corn.

This is mainly because the production of corn has a high scientific and technological content, whether it is cultivation, propagation and promotion, it requires many scientific experiments, consuming a certain amount of manpower and financial resources, so its commercial value is also very high. Generally speaking, the ** of seed corn is several times higher than that of conventional corn. Seed corn is definitely different from ordinary corn, because seed corn is scientifically cultivated by experts, and ordinary corn has no reproductive ability.

In the process of seed corn cultivation, pests and diseases are important factors affecting the yield and quality of corn, the main insect pests in the process of corn cultivation are corn borer, armyworm, red spider, aphid, peach borer, etc., and the main diseases are rough shrinkage disease, brown spot disease, large (small) spot disease, corn sheath blight, rust and so on.

丨What is the impact of even rain on seed corn? Which diseases have a greater impact on the planting process of seed maize? How to prevent it?

In the process of seed corn cultivation, pests and diseases are important factors affecting the yield and quality of corn, the main insect pests in the process of corn cultivation are corn borer, armyworm, red spider, aphid, peach borer, etc., and the main diseases are rough shrinkage disease, brown spot disease, large (small) spot disease, corn sheath blight, rust and so on.

Disease-resistant varieties are selected for planting, and aphids and planthoppers are eliminated with early pesticides before they migrate to the corn fields. It can be used with 40% oxidized happy fruit 3000 times liquid or 50% anti-aphidcarb.

To grow corn, the following methods can be taken:

1. Reasonable dense planting:

The suitable density of high-oil maize is 4000 4500 plants per mu. In order to reduce the number of empty poles and improve the uniformity of the population, the number of seedlings should be about twice that of the suitable planting density infiltration. 4 5 At the leaf stage, the number of seedlings should be times of the suitable planting density; The upper limit of suitable planting density should be the planting density. It can be combined with auxiliary pollination to carry out auxiliary pollination on weak plants, which can eliminate empty stalks and ensure uniform population.

2. Scientific fertilization:

In order to promote plant growth, increase grain weight and oil content, nitrogen, phosphorus and potassium fertilizers should be added. Generally speaking, 1000-2000 kg of organic fertilizer per mu, 8 kg of phosphorus pentoxide, 8-10 kg of nitrogen, 1-2 kg of zinc sulfate, 2-3 grams of nitrogen fertilizer at seedling stage, 5-7 days after jointing. Apply 10 12 kg of nitrogen fertilizer.

3. Chemical regulation:

High-oil corn plants are usually as tall as meters. Controlling high resistance is one of the key measures for high yield of high-oil maize. In general, you can spray 30 ml of corn per acre during a large flare, or a new growth regulator, vitalin, per acre during a large flare.

4. Timely treatment of pests and diseases

High-oil maize has strong resistance to large spot disease, but the incidence of corn borer is higher. This control method can be used for 3 5kg of mites, 3kg of chlorpyrifos and 2kg of carbofuran granules in the large bell period. In the high-incidence area, it can be applied to the pistil again at the silking stage, which can effectively reduce the loss of bamboo shoots and ensure high yield and harvest.

1. Selection of breeding land.

The selection of breeding land is the basic condition for successful maize breeding, and the most uniform planting environment can meet the needs of maize inbred line growth and development, and can promote the reproduction of maize plants and the balance of plant genetic composition. In addition, the selection of breeding land should take into account the frequency and degree of harm of pests and diseases, and the range of changes in the planting environment.

2. Selection of new varieties.

The selection of excellent new varieties should be based on the existing high-yield and high-quality maize varieties or combinations of excellent backbone parents, and the molecular marker-assisted selection method should be used to focus on the development of molecules and markers of maize resistance to dwarf mosaic virus disease, high oil, high lysine lead and high vitamin A-derived traits, and transform them into high-quality and disease-resistant new materials, and use molecular markers to screen the basic materials for breeding and divide the basis of maize heterosis groups to combine disease-resistant and high-quality maize varieties.

3. Sowing seeds in breeding grounds.

Generally, a lower planting density is used, which is slightly lower than that of larger field production, which is 10%-15% lower to ensure the full development of plant characteristics, promote the growth and development of maize inbred lines, facilitate the later removal of weeds and emasculation, and screen out ideal maize plants.

4. Pollination process.

The most important feature of maize is natural cross-pollination, and the field composition of the natural state pollination population is in a highly heterogeneous state, and the individual genotype is in a highly heterozygous state, which determines that in the natural pollination population of maize, the inter-plant phenotype is of little significance, and the trade-off can only be correctly decided through a certain genotype selection process. At the same time, due to the high heterozygosity of individual genotypes, phenotypic selection is unreliable, and a large number of individuals must be tested or verified in the offspring to confirm whether the phenotype is truly inherited. For these reasons, in the process of maize breeding, it is generally necessary to go through multiple generations of selection and comparison before a new inbred line or variety can be bred.

5. Breeding methods.

1) Reincarnation selection method: this method is mainly to select individuals with target traits in a hybrid population to make parents for interactive recombination, when they form a new population, and then identify and select in this new population to re-enter the next round of cycle, and so on, increasing the favorable genes in the hybrid population, and constantly eliminating the unfavorable genes in the hybrid population, thus improving the yield effect of the population.

2) Bicyclic breeding method: The bicyclic breeding method is suitable for the breeding selection of monocross species or commercial hybrids, the method is relatively simple and convenient, it is mainly to use a single crossed species to continuously multi-band self-crossing, and select inbred lines containing excellent genes.

3) Modern biological breeding technology: The more practical modern biological breeding technology is molecular marker and transgenic breeding technology. Molecular marker methods are mainly used in seed purity identification, seed genetic diversity analysis, gene mapping, heterosis, division, etc., which greatly improves the efficiency of breeding.

Transgenic technology is an important way of maize breeding, and the appropriate genes can be selected according to the required target shape and introduced into the crops that need to be improved to achieve the expected results.

1. Understand the flowering period of the parents and determine their respective sowing dates to ensure that the flowering period meets.

2. Determine the ratio of parental planting, usually 1:5 for father:mother, and different combinations are different.

3. Sowing and field management according to conventional techniques.

4. Artificial emasculation: In the female parent is about to draw the male flower is to pull out the male flower.

5. Artificial pollination: collect the pollen of the male parent and send it to the female filigree. It can usually be done twice a day in the morning and in the afternoon, and the effect is good in the morning when there is more pollen.

6. After the corn is mature, the seeds on the mother parent are collected, dried and threshed.

The general steps are like this, and it is best to look at the relevant information for details.