How to refine high-quality seeds?

High-quality seed is an important means of production to ensure high and stable yield of maize, and its production is a systematic project. it is the result of the perfect implementation of all processes such as parent seed reproduction, production technology research, field seed production, seed processing and throughout quality control. Understand the international seed production process, grasp every link of the key production technology, the prophet is the first to win.

Parent seed:

Determine the purity of hybrids

In the breeding of hybrids, the female parent and the male parent came from two independent heterotic groups respectively. The female parent group has the advantages of short plant, large ear, neat silking, smooth silking and good comprehensive resistance, while the male parent group has the advantages of high plant, large amount of pollen and long pollination period. Such parents are born with the advantages of easy seed production and high yield.

When a hybrid performs well and gets permission to go on the market, the breeders have only a small number of parent seeds in their hands. These seeds are propagated and identified in ear rows, and neat and uniform ear rows are selected for mixed harvest, resulting in breeders' seeds. Breeders' seeds are the parent source of future seed production and the initial determinant of seed purity.

After the seed of the breeder was handed over to the production department, the original seed was obtained after one generation of expanded propagation, and the original seed could be preserved in cold storage for many years. Every year, the production department takes a part of the original seed from the original seed, and after two generations of isolation and propagation, the number of seeds needed for field seed production is reached, and the hybrid seed production can be carried out. The quality control of the original seed is very critical, which determines the purity of the hybrid to a large extent, so the purity, purity and germination rate of each batch of original seed should be strictly tested.

Production research:

Efficient production of high quality seeds

Before starting seed production in the field, scientists from the seed production Department should conduct seed production research in order to answer "how to efficiently produce high quality seeds in designated seed production bases." This kind of research began before the hybrids were on the market. For domestic seed companies, the best time to start is from the first year of the regional test, and preferably in the future seed production base. Before large-scale seed production, seed production research should be carried out for at least 2 ~ 3 seasons.

These studies are divided into several parts. The main results are as follows: 1. the suitability of parents in seed production is to observe and record the female and male panicle development, florescence gap and yield characters of parents in the seed production environment. Only combinations with high yield, low risk and low cost of seed production will be approved for listing and further seed production research will be carried out. Second, the study of seed production technology. The main work of this part is to grasp in detail the characteristics, characteristics, florescence, the best sowing time window, and the response to temperature, light and water of a variety of parents. The purpose is to adjust the sowing time of parents to ensure the meeting of flowering time, to explore the row ratio of parents to ensure yield, and to determine the planting density and management mode of high yield. Third, the re-optimization of seed production technology, study through the improvement of various agronomic techniques to further increase the yield and reduce the cost.

Field seed production:

There can be no less isolation and castration.

After mastering a sufficient number of parents and seed production techniques, field seed production can be arranged. The key technical links in this stage are isolation, castration and cultivation management.

The purpose of isolation is to reduce the pollution of foreign pollen to the seed production field and ensure the purity of seeds. The international isolation distance for maize seed production is 300 meters, and international seed companies can select, plan and plant seed fields in strict accordance with this standard.

Male removal is to remove the male ear of the female parent, ensuring that only the male parent can scatter powder in the seed field and produce hybrids. The quality of this work depends on the management area, responsibility and management ability of field technicians. In recent years, the high-power intelligent emasculating machine has developed rapidly in Xinjiang. The emasculating machine can operate 12 ~ 16 lines at the same time, and infrared detectors are installed on each castrated manipulator to accurately grasp the height of corn male flowers. The castration machine adjusts the position of the castration manipulator immediately after receiving the information of the height of the male flower, so as to achieve the goal of accurate castration without excessively harming the male parent plant.

Male sterility technique:

The core competitiveness of seed enterprises

The work of emasculating in the field during maize seed production is time-consuming and laborious, and incomplete or untimely emasculation will affect seed purity, so the development of a new type of male sterility technology is of great value to seed companies. After years of research, American Vanguard Company has launched a new patented seed production technology-SPT. The traditional maize male sterile line is a cytoplasmic male sterile line (CMS), and its commonly used T-CMS is susceptible to leaf spot infection and has a high risk. In the new SPT technology, sterility is controlled by nuclear genes, and the core of the technology is the transgenic maintainer line, which contains a fertile gene, a sterile gene, a pollen lethal gene and a fluorescent marker gene from goldfish, which can produce two kinds of pollen: one is fertile and the other is sterile. The maintainer line produced male sterile line and maintainer line after self-crossing, the maintainer line carried fluorescent marker gene and showed red, and the male sterile line was normal yellow or light yellow. After screening by a specially designed color separator, the two kinds of seeds can be distinguished. The biggest advantage of this technique is that because the male sterile line is a common genic male sterile line and does not contain any genetically modified components, the hybrids produced after mating with normal non-transgenic restorer lines are non-transgenic seeds. Therefore, SPT technology is a method of using transgenic technology to produce non-transgenic seeds (of course, this technology can also be used to produce transgenic seeds). Another advantage of SPT technology is the protection of germplasm resources. In the seed production base, there are only restorer lines and male sterile lines, but no core maintainer lines, which can effectively protect the female inbred lines of the variety from loss.

Seed processing:

A powerful means to improve the brand

After the seed is harvested, it enters the process of seed processing. Seed processing refers to from the ear into the factory to the finished seed out of the warehouse, including many key points of management and technology. We cannot enumerate all of them here, but only two technologies that are important to domestic seed companies: ear drying and seed coating.

Ear drying is a process in which the ears harvested in the seed field are transported directly from the ground to the factory, and the seed moisture is rapidly reduced by drying equipment. Ear drying can reduce the mechanical confusion caused by threshing, advance the time of seed entering the factory, and improve the processing efficiency.

Seed treatment is another secret weapon to improve the quality and value of seeds, which can improve the commerciality of seeds and fully demonstrate the yield-increasing potential of seeds. International seed companies pay close attention to the research progress in the field of international agrochemical industry, and study the formulations of fungicides and insecticides suitable for planting areas, as well as matching seed coating technology through special agronomic departments. Seed treatment has become a powerful means for international seed companies to increase product differentiation and enhance brands.

Quality control:

Control bud rate and purity

From parent seed reproduction, through field seed production, seed processing, until the finished seed is shipped out of the warehouse, in this long seed production process, quality control is throughout the process. Every parent seed, every seed field, every batch of hybrid seeds harvested, and the seeds processed by each step must go through the quality inspection of the quality control department and resolutely eliminate unqualified plots and seeds.

Bud rate and purity are two core indexes of seed quality.

The bud percentage detection method of international seed companies is simpler, more standardized, easier to repeat, and more reliable than the domestic sand table method. In addition, low temperature germination test and accelerated aging test are more stringent and closer to field practice than ordinary bud rate detection. Therefore, the seeds of international seed companies are more resistant to adverse environment and emerge more neatly in production.