Herbicide Tolerant Turfgrasses: Where are we now?

Roundup Ready creeping bentgrass trial conducted at Iowa State University in 2004.  The border roads were conventional bentgrass and were killed by glyphosate while the Roundup Ready turf plots remained unharmed.

Editors note: This is the first part of a series of articles that will review the history of roundup ready turfgrass and the current state of herbicide tolerant turfgrasses.

Do you remember when the topic of herbicide tolerant turfgrasses was all the rave? After all, it’s been since the mid ‘90’s since the development of Roundup Ready creeping bentgrass (RRCB) began. Heck, it’s been almost 10 years since we conducted our first RRCB trials here at ISU.

The Regulatory Process
Many of the studies at ISU were conducted as part of an intensive evaluation process known as an environmental impact statement (EIS). The Animal and Plant Health Inspection Service (APHIS) is the branch of the United States Department of Agriculture (USDA) responsible for evaluating plant biotechnology products to evaluate their plant-pest potential. At the time RRCB was being developed it was the first perennial biotech plant to be reviewed by APHIS.

The environmental impact statement conducted on RRCB included projects that investigated seed germination studies, competition studies, flowering and pollen studies, morphological studies, and nutrient studies. The results of these projects showed that RRCB possesses essentially the same characteristics as conventional creeping bentgrass. Despite these findings, RRCB has faced opposition by groups not wanting to see it registered for release.

The groups in opposition to RRCB generally focus on three major concerns. The first concern is that the herbicide resistant gene will grant the plant a competitive advantage and enable the plant to migrate into areas where it is not wanted. The second concern is that the introduced gene may spread from creeping bentgrass to other closely related species through pollen transfer, therefore making them resistant to glyphosate. The third concern involves the development of resistance in weed populations.

Alfalfa to the Rescue?
Currently RRCB is still awaiting approval by the APHIS and there appears to be no end in sight. However, a recent ruling by the USDA concerning roundup ready alfalfa could provide a glimmer of hope. How could a ruling concerning alfalfa help RRCB? All of the Roundup Ready crops currently on the market are annuals (corn, soybeans, canola, sugar beet, cotton and wheat). Alfalfa is a perennial crop just like creeping bentgrass and many of the concerns raised with RRCB also exist with Roundup Ready alfalfa. The deregulation of Roundup Ready alfalfa was a long process that was eventually settled in the courts.

Roundup Ready alfalfa was originally deregulated by APHIS in 2005. Shortly after this decision, a lawsuit was filed and in 2007 a court issued an injunction prohibiting the sale of Roundup Ready alfalfa and the genetically engineered alfalfa lines returned to regulated status. Then in 2008 the Ninth U.S. Circuit Court of Appeals in San Francisco, CA upheld the 2007 court decision to halt the selling and planting genetically engineered alfalfa until an EIS could be completed. The EIS was completed in December of 2010 and earlier this year APHIS announced its decision to grant non-regulated status for Roundup Ready alfalfa.

What Now?
Traditional breeding practices have greatly advanced the quality and performance of turfgrass species primarily by improving the color, texture, density, and architecture of the plant. The next generation of traits likely to be targeted for improvement includes herbicide, insect and disease resistance along with increased salt tolerance. While these traits would be difficult to develop using traditional breeding methods, they are likely possible using biotechnology.  The roadblock to their release is deregulation from APHIS. There is no doubt that Roundup Resistant turfgrasses would give turfgrass practitioners their most potent weapon against annual bluegrass and could result in reduced chemical loads if used properly. The possibilities could truly be endless…but until deregulation becomes a reality we wonder, and wait.

Marcus Jones
Assistant Scientist