Seed Production

Seed production. It is called the process by which quality seed is obtained in an organized and controlled way, paying rigorous attention to preserving genetic stability and varietal purity. This process must be carried out under rigorous and inviolable standards, aimed at compliance with field operations, transportation, and benefits, among others. Culture and tradition in the production of seeds are recognized as vitally important, since if the same the objective set would not be reached.

Summary

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  • 1 Introduction
  • 2 Physical principles of seed classification
    • 1 Weight separation
    • 2 Separation by size
    • 3 Width or thickness spacing
    • 4 Separation by length
    • 5 By color
  • 3 CATEGORIES OF SEEDS
    • 1 Genetic or original seed
    • 2 Basic or Foundation Seed
    • 3 Registered seed
    • 4 Certified Seed I
    • 5 Certified Seed II
  • 4 HARVEST AND BENEFIT OF SEEDS
    • 1 Considerations for harvesting
    • 2 Considerations for seed drying
    • 3 Treatment or protection of seeds
    • 4 Storage
  • 5 Internal links
  • 6 Source:

Introduction

The seed is the part of the plant that is used to expand and / or preserve a given species, either for consumption or for reproduction. It can be gamic (which comes from the fertilized flower) or agamic (any part of the plant other than the fertilized flower); the first is obtained by sexual means and the second asexual.

Among agricultural inputs, the seed, being the carrier of the genetic potential that determines the productivity of the crop, is an element of great importance in production. For this reason, it constitutes the most important input to achieve high yields in any crop without exception. Choosing the variety, sowing at the appropriate time and the use of high quality seeds are the main pillars of the productivity of a field and if properly managed, they can represent 70% of the success of the agricultural activity.

To obtain good quality seed it is necessary to subject it after harvesting to a series of processes and controls, among which conditioning is one of the most important. The seed as it comes from the field is never found pure, it comes mixed with weed seeds, inert matter etc., so it must be purified so that it can be stored and distributed to producers.

Uniformity is one of the most important characteristics of good quality seed, especially when sowing is done by machine. Seed production constitutes the latest chapter in genetic improvement of varieties. This is an agricultural activity that, based on research, perpetuates the accumulated results after many years of efforts and invested capital.

Physical principles of seed classification

Seeds can be separated from contaminants only if they differ from them in one or more physical characteristics. The size, shape, weight or density, color, texture, electrical properties, are characteristics that allow the seeds to be cleaned and classified by mechanical means.

Hybrid rice seed production field

Weight separation

The weight of the seeds is the characteristic that man has used for a long time to separate these from their pollutants taking advantage of the air currents.

Size separation

The seeds can also be classified by their size, that is, according to their length, width and thickness, which is achieved by passing them over shaking screens or discs and cylinders.

Dried corn seeds and pomegranates

Width or thickness separation

Width separations are performed using flat or cylindrical screens that have round perforations, which may be of different diameter. For separation by thickness, flat or cylindrical screens with oblong or rectangular perforations are used. These separations are achieved by making the seeds rotate on their edge or stand on one of their ends, if the width or thickness of these is less than the perforations they fall through them and if they are greater they do not fall.

Field bean seed

Separation by length

If we are dealing with seeds that have equal width and thickness, they are separated by length. The disk or cylinder separator are the only machines used to separate seeds that differ in length by removing short seed mixtures. These physical properties are the most common, as they are easily exploited in seed conditioning plants. In addition to these properties there are others to effect the separation, but they are less used. For example for texture, color and electrical properties.

Field of sorghum seed

By color

Many seeds differ in color or flexibility. The electronic color separator contains photoelectric cells that detect color differences. This machine is useful in conditioning large seeds. When similar machines are not available, visual and manual separation is the only alternative seed producers have.

SEED CATEGORIES

In the crops in which it is used, its botanical or gamma seed and this has a high level of reproduction such as rice, beans, corn and others, five categories have been established in the seed production process: genetic or original seed, seed basic or foundation, registered seed, certified seed I and certified seed II.

Genetic or original seed

It is the result of the process of genetic improvement, capable of genotypically reproducing the identity of the variety. It must be handled by breeders who obtain and / or study the variety.

From this first phase, the second one, belonging to this category, will be executed, in which the lines already selected will be sown in plots of 4 to 6 m2 where the negative selection will be made again and the phenological and phenotypic characteristics will be studied. In addition, a kilogram will be taken to determine the industrial quality of each line, discarding those with the lowest expression of said character.

After these two phases are finished, there will be between 45 and 60 lines of the initially selected that will be mixed together to produce the basic seed.

Each line will be individually preserved in adequate storage conditions so that they maintain germination for four or five years. Once this stored reserve is used, it will be necessary to start the process or cycle again.

Basic or Foundation Seed

It is obtained from the original seed, produced under the supervision of a plant breeder, in this category it is necessary to strictly comply with the provisions of the Seed Inspection and Certification System established by each country. It is generally carried out in research centers and / or in entities specialized in seed production. As many negative selections will be made as necessary, sowing under the sowing framework described for the original seed.

Registered seed

It is obtained from the seed of the foundation controlled under the certification system and that meets the established quality standards. The soil, like the previous categories, must be free of seeds of other varieties, and / or prohibited weeds. To achieve the above, the field or lot must undergo a rotation process, where chemical disinfection is foreseen prior to sowing. Its production is carried out on specialized farms or estates for this purpose.

Certified Seed I

It comes from the previous category and must be certified by the entity authorized for it. Its sowing is carried out in specialized areas, always under a scheme of rotation and chemical disinfection.

Certified Seed II

It comes from the previous category and is governed by the same production standards.

HARVEST AND BENEFIT OF SEEDS

Considerations for harvest execution

  • It will be programmed according to the installed capacities.
  • It will be executed at the moment in which the field samplings report the optimal humidity for the variety in question (22 to 18%).
  • The harvesting and transport equipment will be specifically designed for this purpose and will be cleaned before the harvest of each variety begins.
  • Each transport will be equipped with an awning or cover to protect the seed from the rain. For each transport, a driver will be issued where the origin, lot, field, variety, category and cut-off time are specified.
  • From the harvest to its reception, no more than 6 to 8 hours should elapse and the maximum time allowed for its reception once it arrives at the drying room will be 12 hours; those items that do not meet this requirement are diverted for consumption. In addition to the above, those transports that have been exposed to rain without the correct protection will also be diverted for consumption.
  • The existence of strange odors will be verified, for example decomposing organic matter, foul odors, fermentations, mold. If any of these odors are present, the production will be rejected as seed and will go to consumer dryers.

Seed drying considerations

  • The dryer will only be used for this purpose, after cleaning before changing each variety.
  • Air temperature to apply 43 º C (110 ºF).
  • Grain temperature: 1 to 2 º C above ambient, but never higher than 35 º C.
  • Final grain humidity: 11.5 – 13.5%.

Seed treatment or protection

It is done to preserve it from fungi and microorganisms in the soil or that are transmitted by the seed itself. It can be dry or wet, there are several technologies that range from a manual process to the use of sophisticated equipment.

The treatment should be carried out only a few days before sowing, since long periods of storage after applying a chemical product to the seed can affect its biology. On the other hand, it is essential in this process to maintain the necessary isolation and cleaning measures to avoid mixing seeds of different varieties.

Storage

  • The seed will be stored taking as an index the daily reception of the dryer, the data of origin and identity of the consignment.
  • The pallets must be grilled, keeping between stowage and roof and between stowage and stowage approximately one meter of space, with 1500 bags of 75kg each maximum.
  • Each variety will be stored in independent pallets distant enough from each other to avoid possible mixtures, and must be identified with the necessary data to make any decision.
  • Maintain periodic technical control on the phytosanitary state, humidity and germination.
  • The broken bags or sacks must be repackaged, prohibiting the existence of grains outside them on the floor or on the pallets that can be transported incidentally.
  • The presence of rodents, birds or other animals that may contribute to the mixing of the varieties within the warehouse will be avoided.
  • A periodic fumigation program will be carried out to avoid the affectations of the seeds by the warehouse pests.

 

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