Herbicide Tolerant Sorghum
By Dan Davidson
DTN Staff Agronomist
February 12, 2007
Cibus, a California-based plant breeding technology company, and the National Grain Sorghum Producers Foundation have formed an alliance with Valent U.S.A. Corp., a leading provider of innovative crop protection products, to develop herbicide tolerant grain sorghum.
OMAHA (DTN) – Grass weeds are the number one problem in sorghum, but unlike corn, producers have limited control options. There are few herbicides available, and there has been no investment in developing glyphosate-tolerant sorghum due to the limited size of the market (only 6.5 million acres of sorghum were planted in the U.S. compared to 78 million acres of corn).
Last fall, DTN reported on the launch of Cibus’ new revolutionary molecular breeding technology that would create new and novel traits without the necessary genetically modified organism (GMO) constraints that create marketing hurdles.
Cibus, a San Diego, Calif.-based plant breeding technology company, announced its own proprietary non-GMO gene conversion technology known as the Rapid Trait Development System or RTDS.
“For the first time since GMO products hit the market more than a decade ago, there is a viable technology that can replicate the attributes of certain GMO crops without the introduction of foreign genetic material,” said Cibus President Keith Walker.
Cibus’ RTDS technology is a molecular breeding technology that enables seed companies to develop plants with novel and commercially valuable traits. However, unlike transformation, RTDS introduces genetic traits through a process where genes naturally repair themselves. Using this process, Cibus can make small changes in the DNA sequence that codes for the gene and ultimately change its function.
Cibus partnered with the National Grain Sorghum Producers Foundation (NGSPF), which is affiliated with the National Sorghum Producers, and Valent U.S.A. Corp., a leading provider of innovative crop protection products, to develop sorghum that is resistant to Select Max herbicide. Select Max contains the active ingredient clethodim, which controls grasses (sorghum is also a grass species).
Walker said that Cibus will develop the trait, the NGSPF will coordinate development of commercial varieties with seed companies and Valent will have sorghum registered on Select Max’s herbicide label. Each company has invested in the technology and through a series of licensing agreements will share the revenue.
Walker said that developing sorghum is his company's first foray into developing herbicide tolerant (HT) crops. “Herbicide tolerance has an easy-to-identify value to the marketplace. It is well-established and an accepted trait.”
“In sorghum, it is hard to control grasses, and there is a need in the market for a more effective control method,” said Walker. “There are a lot of chemistries for controlling broadleaf in cereal grains, but it is more of a problem to control weedy grasses.”
Walker said his company decided to focus on Select Max as a herbicide because there was a need for grass control in sorghum and because the enzyme that Select Max affects was known. And equally importantly, he said, Valent had an interest in being a potential partner.
Why not focus on glyphosate tolerance (GT) instead? Walker said there were already numerous acres of GT corn and soybeans planted in the same geographies as sorghum, and they wanted to stay away from this trait and focus on a rotation herbicide that fits in a farmer’s sorghum rotation with corn and soybeans.
Cibus first clones the gene (that codes for an enzyme that Select Max affects) into a bacterial species. Cibus uses this system as a surrogate model to make the necessary gene changes and then study the results. In this model, it is easy to study the gene for the enzyme that Select Max affects, make small mutations and look for herbicide resistance.
When they are done with the research phase and are confident they know how to alter the right gene to obtain the expected outcome (herbicide resistance), they discard the bacteria and repeat the process in sorghum, modifying the gene without having to clone in a new gene.
Because Cibus is altering a native gene rather than inserting a new gene, the process is not considered genetic modification and therefore does not have to pass the same regulatory and approval processes.
“There are no regulatory issues at all,” said Walker. “The USDA, FDA and EPA have responsibility to approve safety of products moving into the public sphere through a standard set of procedures. And each company has responsibility to make applications for approval. We approached the USDA with an application and the USDA granted us an exemption from making application as a transgenic organism. But, every country has a different procedure. Instead, we plan to conduct a voluntary dialogue with regulatory agencies to keep them appraised to make sure it always meets their approval.”
Walker said that the timeline for trait development is 24 to 30 months, followed by another 24 months to develop a commercial hybrid. He expects to see the first commercial launch in four to five years. “By 2009 we will be able to more accurately predict when the product will come to market, he said."
The trait will be licensed and marketed through commercial seed companies who will put it in their most elite germplasm. The NGSPF plans to use revenues derived from this partnership to reinvest in
sorghum research and development as part of a long-term program for sorghum improvement.
Walker said he is not worried about any yield drag issues because he is confident the gene and its enzyme will be sufficiently resistant to the herbicide and that seed companies will put it into their best hybrids.
Walker said, “transgenes randomly jump into the genome and may disrupt endogenous natural processes. This technology is not disruptive to the genome, and we intend to screen small plants for the best response. Our technique is less likely to create mutations that cause yield drag.”
"This is an exciting project," said NSP CEO Tim Lust. "With new grass control options, producers will begin considering planting sorghum in fields where that may not be an option now. This is a clear win for sorghum producers."
"A recent Kansas State University survey of more than 600 sorghum producers from across the United States identified grassy weed control for grain sorghum as their number one research priority," said Joseph Short, product manager for Valent. "Select Max provides fast and complete control of emerged annual and perennial grassy weeds in over 100 crops, including soybean, sunflower, cotton, and sugar beets. Sorghum producers will see increased convenience, yield and profits when they can selectively control grasses with an over-the-top application of Select Max."
