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 Enquiries SEED News - nov/dec 2007
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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 law concerning cultivar protection allows breeders to use genetic material from other companies in their breeding programs, based on the principle that the success of any breeding program relies on having sufficient genetic variability upon which to exert selection. Regarding this issue, I'd like to know if it is legal to freely use patented events like RR soybean or Bt cotton in plant breeding programs."
It is entirely possible for any breeder to enter the seed crop fields of third parties and collect seed samples to be used in its own breeding program. This means that some time after that, hopefully, there will be a new cultivar that, among other features, will show those inherited from the genetic material collected at the seed crop field. This will in turn benefit the society through the increase in competitiveness by the new cultivar. Regarding patented events, the situation is different to that of conventional cultivars, so that breeders do not have the right to use, freely, patented traits, which are regulated by a specific law.
"Our company has a portfolio with more than ten soybean cultivars, which covers our clients' needs. This year one of the cultivars showed a low germination percentage, causing some difficulty in coping with farmers demands. Could it be that this cultivar bears the trait of having seeds of low physiological quality?"
The physiological quality of seeds results from several factors, some of which are closely related to genetic traits. This results in some cultivars having no problems in seed production, whereas for others this feature may be impaired. In your case it is probable that the cultivar carries some traits that make it difficult to produce seeds of appropriate levels of seed coat composition and thickness and water uptake capacity, among other features. To obtain seeds of high physiological quality from cultivars that carry unfavorable features, demands high technology for field inspection, at harvest and during all stages of seed processing, such as drying, cleaning and storage.
"I was commissioned by my company to identify possible storage locations for corn seeds, so that we remain as close as possible to our customers when distribution time arrives. Could you mention some useful tips to help choose the adequate storage sites?"
It's a good idea to keep storage sites close to the growers that will demand the seed. In general corn seeds are made available to growers through retailers which don't necessarily possess adequate storage facilities. Hence, it is the seed company who must provide these facilities and it should consider a minimum storage period of 18 months, since any remaining seed will then be able to maintain its quality until the next growing season. We recommend that seed moisture level must be kept between 12%-13% in storage with temperature at 20°C and relative humidity of 50%-60%. This recommendation applies to corn seeds that have high physiological quality at the time of storage.
"We are a group of soybean seed producers with several years in the business that are currently experiencing trouble with the distribution of seed. Our seed is produced from July through October and the planting season of our growers starts in November. This leaves us with a short period to prepare the distribution schedule for our seeds. We would like to know if there is a significant loss in the physiological quality of soybean seed stored from April/May until October/November."
Your company is working based on a schedule that leaves a very narrow margin for the chain of production involving processing, analysis and distribution of seed. It is worth considering other alternatives such as using the seeds produced throughout the summer and harvested in April/May. With this scheme, and under the normal subtropical climate of Brazil, seed germination percentage decreases between two to three percentage points in seed lots with initial germination above 85%. Seeds with high quality can be stored under ambient conditions for periods up to eight months.
"I have read your article on Bt cotton, in which it is advised to use refuge areas, i.e. areas to be sown with conventional cotton varieties. Since these areas will almost certainly yield less and at a higher cost, I will appreciate an explanation on the need for such a strategy."
The Bt cotton varieties control some species of insects and since these possess high genetic variability, even within the same species, most probably some insects will turn resistant to Bt cotton. To avoid the increase on the resistant population, the refuge area will be used by the resistant strains to breed with the susceptible population, yielding generations of susceptible insects that will warrant cotton growers the effectiveness of the Bt event.
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