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 Enquiries SEED News - mar/apr 2004
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This section is coordinated by the professors from the Federal University of Pelotas/Brazil -
www.ufpelsementes.com.br -, whit the objective to answer the inquiries sent by the readers.
Send your question to e-mail: silmar@seednews.inf.br
I've been observing that in my stationary bin dryer there is a difference of up to five percent points of moisture content among the different seed layers. How can it be solved?
The seeds are hygroscopic materials, and due to that, they lose and gain moisture content as function of the air relative humidity. In the stationary bin dryers, when very low relative humidity is used, those seeds close to the air entrance dry at very low moisture contents, while the most distant seeds remain with higher moisture, originating this difference of five percentage points. The solution is to finish drying the seeds with higher relative humidity (50 to 60%), so that the moisture difference is minimized.
I usually buy for my garden, flower seeds in aluminum packages. However, with certain frequency they don't germinate (zero%). Are there explanations for it?
A seed with low moisture content in impermeable packing, as it is in the case of aluminum, has a storage potential usually superior to three years. In your case, what might have happened is a lack of quality control of the company, that did not verify the moisture content of the seeds and its germination before packing them. Get in touch with the seller.
The seeds of hybrid corn, sunflower, sorghum and of many vegetables, really have been demonstrating through the years their benefits, in productive terms. Why in soybean we still don't have hybrid seeds?
Hybrid seeds of soybean, certainty, will have a superior performance compared to the normal ones; however, the bottle neck is in the production process. It is considered that we will also have hybrid seeds of this species in the future.
It seems that the coating process is coming to help the production technology. Nowadays, for the great cultures, such as corn, what can be indicated?
The corn is, usually, treated with fungicide and, as it is heavily attacked by insects, it is presumed that the coating process for corn will consist of a fungicide, insecticide and the polymer to form the coating system. In fact, a coated corn seed is well-protected, easy to plant and standing out easily from the other ones.
Grading soybean seeds according to size, really came to help the sowing process, however, I have doubts in terms of terminology used for seed size. What does mean a soybean seed screen six?
Following the same terminology used for corn, the number of the screen is the one that the seed is kept; so, a screen six, means that seeds has a diameter between 6.0 and 6.5mm.
In my walks through the soybean crops in the end of the year, it could be observed that many fields didn't have a good stand. There were some of them in that less than 30% of the seeds got to emerge. Could you comment about this poor seed performance?
The seeds, for germinating, need water, adequate temperature, substratum and some of them also need light. If those conditions are all right, we have to verify the sowing depth and phytotoxic materials. Lately, the phytoxicity has been the main problem, caused by herbicides, placement fertilizer very close to the seed and by poor dosages of materials that are added to the seeds, such as fungicides and micronutrients. There is the perception that emergence problems are caused by low quality seed, however, that rarely happens, unless you want to save in the seed purchase. The price can always be lowered if quality can also be lowered.
I don't ignore that the seed is an essential input to establish a crop. How can a reliable seed be obtained, because in a market, so disputed and competitive, many materials are offered?
Summarizing, a reliable seed is the one from an adapted and tested variety or hybrid, in that its quality was properly determined and followed. You find it in organized systems where that there are the proper accreditation for seed producers and sellers. A good system, accepted universally, is the seed certification, in other words, a certified seed is a reliable seed, which does not mean that there are not other systems.
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