Bayer's Pan American Weed Resistance Conference wound up Jan. 21 with a workshop led by Harry Strek, the company's head of integrated weed management and weed resistance biology. The workshop topic, gene stacking, triggered some heavy debate, indicating a division of opinion between those who love the concept and those who are nervous or even downright scared of its implications.
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| Bayer's Harry Strek led a workshop on gene stacking at the company's Miami conference on herbicide-resistant weeds. |
Gene stacking refers to the combination of more than one GM trait in a specific variety. An early example was corn with both glyphosate resistance and Bt insect protection. That looked like, and proved to be, a great advance in corn production. It was introduced without much controversy. But now, with plant breeders piling in multiple genes, more questions are being asked.
How, for example, would a soybean grower handle volunteer corn carrying both the Roundup Ready and Liberty Link herbicide tolerance traits and maybe other such traits as well? A Bayer executive agreed that "just stacking in everything is problematic. We have to be very careful."
Several delegates raised concerns about shrinking choice in the marketplace, picturing a scenario where just a few hybrids (in the case of corn) remain on the market but offer resistance to all or most herbicide modes of action.
"That would limit my choice," said one, "and I'd have to pay for traits I don't need or want."
In response, it was noted that multistacking of herbicide tolerance traits offers growers more choice and flexibility in the sense that whatever weeds -- conventional or herbicide-resistant -- appear in the crop, they can probably be controlled.
Another delegate noted that multistacking could convince growers that the technique offers a quick fix for any weed or pest control problem that comes up, and that might deflect attention from good management practices and more permanent, longer-term solutions such as the need for new modes of action.
As in other areas of research and development in the crop protection field, multistacking is not without its proponents and opponents. Growers can expect to hear plenty of arguments, pro and con.