This section is coordinated by professors from the Federal University of Pelotas/Brazil, with the aim of answering inquires sent by the readers. Send your questions to

    As corn seeds do widely vary in terms of size, could you comment on how many seeds there are in one kilogram?

    Corn seeds are sold by number of seeds per kilogram and by type, namely round or flat seeds. For the small variety, 4.5 seeds are necessary for one gram, while for large seeds only 2.5 seeds are necessary for one gram. As we can see, the difference between the largest and the smallest seeds is more than 70 percent.

    When visiting the irrigated rice fields in my region, I notice that some are very clean, while in others there seem to be many things growing along the rice fields. Could you comment on this difference?

    In the cultivation of rice – as in other crops as well – there are farmers who use low-tech methods, by using their own low-quality seed. As these farmers generally do not use high-quality seed of improved varieties, their production fields become infested with seed of weeds which are difficult to control (such as red rice). They do not use varieties that are resistant to a total herbicide that can control weeds.

    I was traveling in the Andean region of Bolivia, enjoying the good and beautiful things of the country. Among the many interesting things in the region, one caught my attention--a kind of sweet white corn that Bolivians consume in large quantities. Is it possible to produce this type of corn on sites of lower altitude?

    Indeed, the Andean white sweet corn is delicious, and it stays tender for several days, along with potatoes, the main dish of the region. Unfortunately, this type of corn does not produce seed in low-lying regions. Many attempts have already been made; however, they did not survive in order for the genetic characteristics of Andean white sweet corn to be incorporated in other materials that produce in a wider range of altitudes.

    In the latest issue of SEEDnews, July 2011, there is an excellent article about the seed business meetings that are held during the annual congress of the International Seed Federation (ISF). I wonder if you could explain how people communicate and finalize negotiations?

    Communication at the congress is in English, and they use many gestures in order to avoid doubts about what is being negotiated. Once parties have agreed on a deal, the next step is to sign a contract, which may occur during the ISF event or after a few days. Currently, with the speed and quality of media, the achievement of business transactions is becoming easier.

    This year, I produced more than 50 tons of soybean seeds from six cultivars; however, I have lost 30 percent of my seed due to low germination. In the germination test from the newly harvested seeds, all lots of all varieties were more than 80 percent germinated, but after four months, many lots were less than 80 percent germinated. How can this be explained?

    Soybean seed is very affected by field deterioration; in other words, it cannot retain its high physiological quality in the field for a long time, when exposed to adverse conditions (especially humidity). In your case, probably lots of low-quality seeds were harvested after remaining in the field with 13 percent moisture for some days. It is recommended that soybean seed is harvested as soon as it reaches 18 percent moisture.

    There is a perception among farmers that seed treatment is essential to the success and sustainability of the business. To that end, is industrial seed treatment—in other words, when seed leaves the processing unit already treated—available currently?

    The industrial treatment of seeds is a universal trend, involving products, equipment and trained staff—and that does not develop overnight. However, there are several companies that are already prepared to provide this service.



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