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 Consults SEED News - july/aug 2003
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This section is coordinated by the professors from the Federal University of Pelotas -
www.ufpelsementes.com.br
Send your question to e-mail: silmar@seednews.inf.br
I´ve heard, in many meetings with my colleagues, that some states of Brazil have lowered the minimum standard for seed commercialization. Please, could someone explain to me how are these decisions taken?
Indeed, some of the states have already lowered the minimum standard for seed commercialization and others are in an evaluation period. In the wheat case, the problem was the rain that had occurred during harvest, having as a consequence the beginning of the germination process with seeds still on the ear. So, as many seed lots were below the standard germination of 80%, there was a necessity of changing the current quality standards. The information about the quantity of the seeds that had less than 80% of germination was obtained from seed testing labs.
The article about seeds certification, published on SEED News on the May-June edition was enough elucidative, however, I would like to know if there is any possibility that another group of people could do the certification of the several processes that involve our agriculture nowadays.
The seeds certification process has already been used over half a century, therefore with an highly qualified staff. The principles of certification that are used in the distinct processes involving our agriculture nowadays are practically the same. There are many countries that for more than a decade use the same staff to carry out the seed certification and other processes, therefore, saving on costs. Having a certification agency for each one of the processes, raises the price of the final product.
Few years ago, soybean seeds weren't classified by size, and today almost every commercialized seed is. Aware of that, I ask: how long are we going to wait in order to have every soybean in the market treated?
Nowadays, in Brazil more than 85% of soybean seeds are treated, and almost all by the own farmer, just before sowing. This situation is changing little by little, and if more producers start offering their seeds already treated, there will be a significant increase of the treatment at the seed processing plant of each seed producer, because nobody wants to be left behind. By the risks associated to the soybean seeds market, it is a difficult decision.
I've heard from my grandfather that vegetable seeds can't be dried in the sun, because they loose their quality. Is it true?
We also hear a lot that seeds can not be dried in the sun.
However, it's not true: seeds can be dried in the sun, as long as they are moved with certain frequency. Drying the seeds in the sun with more than 25% moisture content, will provide a faster process, therefore, minimizing their respiration. On the other hand, drying in the shadow will be slow, putting in risk the quality of the seeds. The research with vegetables seeds was for many years done almost exclusively by private seed companies, who do not use to publish its results. Currently, there's already a good stock of published material.
How can we minimize the problem of wheat seed germination on the ear, which affects so much the seed as well as the industrial product?
The best way is to introduce a dormancy character in the seeds, so, if it rains during harvesting, there will not be so much damage.
The density of sowing recommended for irrigated rice seems to be changing. From 200kg/ ha, lowered to 150, and I realized that for some materials it is recommended to use only 70kg/ha. Could you comment about it?
In fact, irrigated rice seed started being so valorized that sowing more than necessary is a waste of money, and sometimes even of production, when the plant population becomes extremely high. There are genetic differences in the capacity of tillering among the materials. Therefore, from one that tillers a lot, it is possible to use fewer seeds, as in the 70kg/ha case. So, based on these results we can conclude that when the sowing density is lower, there should be a better distribution of the seeds, because the compensation capacity of the plants has limits.
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