Confirmation and characterization of the first case of acetolactate synthase (ALS)-inhibitor resistant wild buckwheat (Polygonum convolvulus) in the United States
Pandian, B.A., Friesen, A., Laforest, M., Peterson, D.E., Vara Prasad, P.V., Jugulam, M. (2020). Confirmation and characterization of the first case of acetolactate synthase (ALS)-inhibitor resistant wild buckwheat (Polygonum convolvulus) in the United States. Agronomy, [online] 10(10), http://dx.doi.org/10.3390/agronomy10101496
Plain language summary
We have found a mutation that confers resistance to group 2 herbicides in wild buckwheat.
Wild buckwheat (Polygonum convolvulus L.) is a problem weed and ALS-inhibitors (e.g., chlorsulfuron) are commonly used for its management. Recently, a population of wild buckwheat (KSW-R) uncontrolled with ALS-inhibitors was found in a wheat field in Kansas, USA. The objectives of this research were to determine the level and mechanism of resistance to chlorsulfuron and cross resistance to other ALS-inhibitors in the KSW-R population. In response to chlorsulfuron rates ranging from 0 to 16x (x = 18 g ai/ha), the KSW-R wild buckwheat was found >100-fold more resistant compared to a known ALS-inhibitor susceptible (KSW-S) wild buckwheat. Also, >90% of KSW-R plants survived field recommended rates of sulfonylurea but not imidazolinone family of ALS-inhibitors. A portion of the ALS gene covering all previously reported mutations known to bestow resistance to ALS-inhibitors was sequenced from both KSW-R and KSW-S plants. The Pro-197-Ser substitution that confers resistance to the sulfonylurea herbicides was found in KSW-R plants. Our results support the evolution of high level of chlorsulfuron resistance as a result of a mutation in the ALS-gene in KSW-R buckwheat. This is the first case of resistance to any herbicides in wild buckwheat in the US.