TY - JOUR
T1 - Target enzyme-based resistance to clethodim in lolium rigidum populations in Australia
AU - Saini, Rupinder Kaur
AU - Malone, Jenna
AU - Preston, Christopher
AU - Gill, Gurjeet
N1 - Publisher Copyright:
© 2015 Weed Science Society of America.
PY - 2015/10/1
Y1 - 2015/10/1
N2 - Clethodim resistance was identified in 12 rigid ryegrass populations from winter cropping regions in four different states of Australia. Clethodim had failed to provide effective control of these populations in the field and resistance was suspected. Dose-response experiments confirmed resistance to clethodim and butroxydim in all populations. During 2012, the LD50 of resistant populations ranged from 10.2 to 89.3 g ha-1, making them 3 to 34-fold more resistant to clethodim than the susceptible population. Similarly, GR50 of resistant population varied from 8 to 37.1 g ha-1, which is 3 to 13.9-fold higher than the susceptible population. In 2013, clethodim-resistant populations were 7.8 to 35.3-fold more resistant to clethodim than the susceptible population. The higher resistance factor in 2013, especially in moderately resistant populations, could have been associated with lower ambient temperatures during the winter of 2013. These resistant populations had also evolved cross-resistance to butroxydim. The resistant populations required 1.3 to 6.6-fold higher butroxydim dose to achieve 50% mortality and 3 to 27-fold more butroxydim for 50% biomass reduction compared to the standard susceptible population. Sequencing of the target-site ACCase gene identified five known ACCase substitutions (isoleucine-1781-leucine, isoleucine-2041-asparagine, aspartate-2078-glycine, and cysteine-2088-arginine, and glycine-2096-alanine) in these populations. In nine populations, multiple ACCase mutations were present in different individuals. Furthermore, two alleles with different mutations were present in a single plant of rigid ryegrass in two populations.
AB - Clethodim resistance was identified in 12 rigid ryegrass populations from winter cropping regions in four different states of Australia. Clethodim had failed to provide effective control of these populations in the field and resistance was suspected. Dose-response experiments confirmed resistance to clethodim and butroxydim in all populations. During 2012, the LD50 of resistant populations ranged from 10.2 to 89.3 g ha-1, making them 3 to 34-fold more resistant to clethodim than the susceptible population. Similarly, GR50 of resistant population varied from 8 to 37.1 g ha-1, which is 3 to 13.9-fold higher than the susceptible population. In 2013, clethodim-resistant populations were 7.8 to 35.3-fold more resistant to clethodim than the susceptible population. The higher resistance factor in 2013, especially in moderately resistant populations, could have been associated with lower ambient temperatures during the winter of 2013. These resistant populations had also evolved cross-resistance to butroxydim. The resistant populations required 1.3 to 6.6-fold higher butroxydim dose to achieve 50% mortality and 3 to 27-fold more butroxydim for 50% biomass reduction compared to the standard susceptible population. Sequencing of the target-site ACCase gene identified five known ACCase substitutions (isoleucine-1781-leucine, isoleucine-2041-asparagine, aspartate-2078-glycine, and cysteine-2088-arginine, and glycine-2096-alanine) in these populations. In nine populations, multiple ACCase mutations were present in different individuals. Furthermore, two alleles with different mutations were present in a single plant of rigid ryegrass in two populations.
KW - ACCase gene
KW - butroxydim
KW - clethodim
KW - resistance mechanism
KW - target-site mutation
UR - http://www.scopus.com/inward/record.url?scp=84941089871&partnerID=8YFLogxK
U2 - 10.1614/WS-D-14-00176.1
DO - 10.1614/WS-D-14-00176.1
M3 - Article
AN - SCOPUS:84941089871
VL - 63
SP - 946
EP - 953
JO - Weed Science
JF - Weed Science
SN - 0043-1745
IS - 4
ER -