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 Enquiries SEED News - july/aug 2004
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This section is coordinated by the professors from the Federal University of Pelotas-Brazil, with the objective of answering the inquiries sent by the readers.
Send your question to e-mail: silmar@seednews.inf.br
The tetrazolium test has become almost a routine in seed quality programs. So, I would like to know in the case of soybean, if the seeds germinate after they are submitted to the test?
The test consists in submitting the seeds to embibe in a tetrazolium solution that will react with the living parts of the seed, serving as base for the evaluation. The procedure does not inhibit the seed germination process, however the follow up with the regular germination test, is not recommended, because some injury may occur during the imbibition process of the tetrazolium test.
Please, could you to comment on the situation of genes patenting, as it was published in the SEED News magazine edition VIII nº 3.
The genes protection by patenting is the discussion of the moment in several countries. It seems that there is a consensus that only the identification of a gene is not enough to patent it, as it is in the case of Brazil. Something to be patent must fulfill the characteristics of the innovation, inventive activity and industrial or others applications. It also seems that there is a consensus that this protection will only have effect for different species, in which the gene was identified and characterized.
I know that seeds are sold based in their physical and physiological quality.
I would like to know how many seeds are used to determine the germination percentage of a seed lot?
The germination test, according to the rules of seed analysis, is accomplished with 400 seeds, representing the whole lot. Using corn as an example, a lot of 20 tons has about 60 millions seeds that are represented by the 400 seeds that were put to germinate. Therefore, one seed corn from a lot of 20 tons will represent 150.000 seeds. For this representation to be real it is indispensable that sampling be properly accomplished.
Is it possible to find, nowadays, conventional, genetically modified and organic seeds, I ask you to explain how the seed quality tests are done for the organic seeds?
ISTA (International Seed Testing Association) is the one that elaborates theinternational rules for seed analysis, and it does not make distinction between classes or seed categories for the analysis procedures. The germination test is the same for conventional, genetically modified and organic seeds.
I liked the article about the sowing process, published on SEED News VIII nº 3, but I would like to know why sowing is not recommended at nigh?
As the authors of the article mentioned, the sowing is one the factors that most influences the yield. This way, the sowing process must be followed by several procedures, such as adjustments and sowing speed, sowing density and controls, in which the seed flow is observed. For this control, the daylight is very important. It is common that seed flow problems occur in the sowing process, which requires a prompt solution to avoid empty spaces in the crop.
I recently received a visit from a seed salesman with a very interesting offer. The proposal was selling to me seeds in a way that my soybean production field had 300 000 pants per hectare, in other words, he was trying to sell plant/hectare instead of the traditional kg/ hectare. I liked the idea, because what really matters is the number of plants per area, not the weight. Therefore, I would like to know how does the salesman estimate the stand that I desire ?
The progresses in seed technology were big in the last years, where seeds are treated, receive coating, are classified by size and they are evaluated not only by their germination, but also by their vigor and, sometimes, by their sanitary state. In this sense, you probably received a salesman from a producer that classifies his seeds and evaluated the quality also by vigor and maybe by health tests.
Therefore, based in the weight of the seed and in its physiological quality it will estimate the quantity of the seeds that should be used to provide 300 000 plants of soybean per hectare.
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