We've been hearing a lot about the promises of genetically modified organisms (GMO). Herbicide resistance is one trait that companies have successfully conferred in crops. Currently, there is a whirl of activity going on in this area with turfgrass — especially bentgrass. Using gene-transfer techniques, scientists have successfully developed glyphosate- and glufosinate-resistant cultivars of plants such as corn, soybean and canola. These herbicide-resistant plants have caused a revolution in farming practices and drawn the ire of anti-GMO advocates both here in the United States and abroad. The same technology is now being used to develop bentgrass cultivars resistant to glyphosate.

Poa annua is a serious weed in bentgrass turf. Because of similar herbicide tolerances between the two, it is very difficult to selectively control Poa in a stand of bentgrass. However, with a green planted with these glyphosate-resistant bentgrass cultivars, you would be able to spray glyphosate on the turf and quickly kill any Poa that may be competing with the bentgrass without harming the bentgrass.

Why aren't these bentgrasses on the market yet? Some people are concerned that these herbicide-resistant bentgrasses would hybridize with other closely related wild Agrostis species. There is the possibility that such hybrid plants have the potential to become weeds that won't be controlled by glyphosate.

Rutgers University scientists teamed up with a contingent from the University of St. Andrews, Scotland, to determine the likelihood of these glyphosate-resistant Agrostis species developing under actual field conditions. They used Cobra creeping bentgrass (Agrostis stolonifera) as well as four related species: A. canina, A. capillaris, A. castellana and A. gigantea. Glyphosate-resistant hybrids were recovered between creeping bentgrass and A. capillaris and A. castellana at frequencies of 0.044 and 0.0015 percent, respectively. These frequencies were considerably lower than occurred among the creeping bentgrass plants within the experimental plot (0.631 percent). No hybrids were recovered with A. gigantea or A. canina. Among the factors that influenced hybridization were distance from the pollen source of the glyphosate-resistant plants, wind and overlapping flowering times between species. This research shows that hybridization can occur in nature but at a very low frequency.

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