|
 Enquiries SEED News - sept/oct 2007
|
|
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
"I have been working with wheat seeds for several years and I got used to measuring their volumetric weight. I know there is a close relationship between volumetric weight and grain quality, so I would like to know if there is also a close relationship with seeds physiological quality?"
The volumetric weight of a seed lot is a function of the mass of each individual seed by its volume as well as seed size. In the case of wheat, there is a great effect of the deterioration on seed mass, causing through this, a close relationship with its physiological quality, that is, the lower the volumetric weight, the lower the seed physiological quality. With other species this may not occur, as the case on soybean seeds. On them, small seeds present a higher volumetric weight but their physiological quality is the same as the big ones.
"In the company I work at I am in charge of drying rice seeds. Therefore, I would like to have explained why do the seeds increase around 2% their moisture content after the finishing the drying process, that is, I consider the drying of a rice seed lot finished when it reaches 11% moisture and, two hours after, I evidence that the moisture of the same lot is 13%."
It occurs because during drying the seeds present a moisture gradient that concentrates more in the core than in the periphery of the seed and, as some kinds of moisture readers, such as Universal type, they are affected by seed peripheral moisture, the moisture content found is lower to the real one. In order to correct such discrepancy there is the need for using suitable moisture readers or taking a seed sample and waiting some minutes before performing the moisture determination, so that moisture homogenization inside each seed can occur.
"In the past years I have adopted the culture of second crop maize, that is, I harvest soybeans and, right after, I sow maize in the same area, then maximizing the property use. I notice that with maize there is a large emergence of soybean seeds; so, I would like to know why this occurs because it seems the seeds present some post-harvest dormancy and such emergence is not noticed."
Soybean seeds do not present post-harvest dormancy type but they do present hard (those that do not imbibe in water) seeds dormancy. In commercial varieties the percentage of hard seeds rarely reaches over 3%. Emergence occurrence in large quantities of soybean seeds is explained by the harvest loss that, under normal circumstances, is around 2% of the production, or 50kg/ha. Such amount is equivalent to 35 seeds/m², explaining the soybean green carpet along with maize.
"When programming seed production we must take into account the multiplication rate of a seed and, from this, make the proper adjustments. In this way, I would like to know how to proceed for soybean seeds."
Programming seed production is crucial to any company success because producing more that needed, means selling part as grain, and producing less, means losing a market share. Specifically for soybeans, in a normal sowing, it can be considered 1:20, that is, one seed will produce 20 commercial seeds. According to the numbers, it is easy to verify that it is a big loss because a soybean plant produces over 80 seeds. Such loss is caused by reasons that vary from failure at emergence (which is not 100%) to rejection of production fields due to rain or other problem, losses in processing such as cleaning and grading and physiological quality, due to low germination.
"I know that seeds production became an increasingly professionalized activity and for that several adjustments have been necessary, among them the payment of royalties to a variety obtainer and the technological tax to a patent owner. In this way I would like to know how such licensing are done?"
With regards to royalties, the seed producer obtains the licensing from the variety obtainer by means of a contract in which, among other items, the percentage to be paid to the obtainer for each seed lot sold is shown; there are other ways to pay, however they are not so usual. With regards to the technological tax, the license must be obtained from the patent owner - that in the case of Brazil includes soy RR, maize LL, cotton Bt, and rice Clear Field. For production of seeds the obtention of both licenses is needed, an easy procedure in a normal relationship between the parties. However, in case of disagreement, the license can be denied and the farmer does not receive superior materials protected by law (we already have some examples).
|
|
............
|
