First cases of herbicide resistance of Tripleurospermum inodorum in the Czech Republic

Abstract

Tripleurospermum inodorum (L.) Sch. Bip. is one of the most economically important and yield-reducing weeds in cereals in Europe. Random and systematic monitoring of this weed might provide an early warning for the farmers and slow down the pace of the evolution of herbicide resistance. This study aimed to identify resistant populations of T. inodorum in the Czech Republic and elucidate their possible resistance mechanism/s. Monitoring and screening of T. inodorum for herbicide resistance against acetolactate synthase (ALS) inhibitors and synthetic auxins was carried out. Greenhouse experiments and molecular-genetics studies were conducted to characterize the resistance. While all the tested populations were found to be susceptible to synthetic auxins, two populations (MATIN 2 and MATIN 4) were found to be resistant against tribenuron (ALS inhibitor). However, their cross-resistance to florasulam was not confirmed. The resistance mechanism detected was the target-site substitution of Pro197 at the ALS gene. The two populations carried different point mutations: Pro197Ser (MATIN 2) and Pro197Gln (MATIN 4). This is the first study in the Czech Republic to identify the survival mechanism in T. inodorum for resistance to ALS-inhibiting herbicides. Our results from this research will provide basis for resistance management in T. inodorum in the Czech Republic and other countries.

Keywords

• als-inhibitors resistance
• pro197 mutations
• scentless mayweed
• target-site resistance
• tribenuron