Multiple herbicide resistance in littleseed canarygrass (Phalaris minor): A threat to wheat production in India

Abstract

Littleseed canarygrass (Phalaris minor Retz.), a troublesome weed of wheat in India, has evolved multiple herbicide resistance across three modes of action: photosynthesis at the photosystem II site A, acetyl-coA carboxylase (ACCase), and acetolactate synthase inhibition.The multiple herbicide-resistant (MHR) populations had a low level of sulfosulfuron resistance but a high level of resistance to clodinafop and fenoxaprop (ACCase inhibitors). Some of the populations had GR50 (50% growth reduction) values for clodinafop that were 11.7-fold greater than that of the most susceptible population.The clodinafop-resistant populations also showed a higher level of cross-resistance to fenoxaprop (fop group) but a low level of cross-resistance to pinoxaden (den group). Although clodinafop and pinoxaden are from two different chemical families (fop and den groups), their same site of action is responsible for cross-resistance behavior. The populations that were resistant to four groups of herbicides (phenylureas, sulfonylurea, aryloxyphenoxypropionate, and phenylpyrazolin) were susceptible to the triazine (metribuzin and terbutryn) and dinitroaniline (pendimethalin) herbicides.The P. minor populations that were resistant to the aryloxyphenoxypropionate and phenylurea herbicides were effectively controlled by the sulfonylurea herbicide, sulfosulfuron. In the fields infested with P. minor that was resistant to clodinafop, a sulfosulfuron application (25 g ha -1 ) increased the wheat yield by 99.2% over that achieved using the recommended rate of clodinafop (60 g ha -1 ). However, the evolution of multiple resistance against the four groups is a threat to wheat production.To prevent the spread of MHR P. minor populations, as well as the extension of multiple resistance to new chemicals, concerted efforts in developing and implementing a sound, integrated weed management program are needed.The integrated approach, consisting of crop and herbicide rotation with cultural and mechanical weed control tactics, should be considered as a long-term resistance management strategy that will help to sustain wheat productivity and farmers' income.

Cross-resistance patterns of winter wild oat (Avena ludoviciana) populations to ACCase inhibitor herbicides

“…Similarly, of the 25 diclofop-resistant accessions of Italian ryegrass (Lolium multiflorum), five were resistant to pinoxaden (Kuk et al 2008). Chhokar and Sharma (2008) also reported the same cross-resistance pattern in little seed canary grass (P. minor). However, the cross-resistance observed in our study along with other sparse instances may imply that the selection pressure from other ACCase inhibitors can result in crossresistance to pinoxaden.…”

“…This has been demonstrated in a number of studies. For example, a tralkoxydim-resistant biotype of wild oat (A. fatua) (Uludag et al 2008) and clodinafop-resistant population of little seed canary grass (P. minor) (Chhokar and Sharma 2008) have shown crossresistance to pinoxaden. Cruz-Hipolito et al (2011) also found that the two A. fatua biotypes from Chile and Mexico were resistant to APP, CHD, and PPZ herbicides.…”

Evaluation of Fenoxaprop-P-Ethyl Resistant Littleseed Canarygrass (Phalaris minor) in Pakistan

“…has been distributed throughout the world and described as a troublesome weed for wheat, barley, vegetables, rotational crops and several other winter crops (Singh et al, 1999;Jabran et al, 2010). P. minor can cause up to 95% of yield reduction in wheat (Chhokar and Sharma, 2008). Manual control of P. minor is difficult because of its mimicry with wheat plants until flowering.…”

“…Many P. minor biotypes have evolved cross and multiple resistance to herbicides, having different modes of action in different parts of the world (Heap, 2015). The multiple resistance problem of P. minor at a few locations in India is so severe that it is causing huge yield reductions (Chhokar and Sharma, 2008). To prevent it from spreading to other fields and the further build-up of the herbicide resistance problem, early detection is essential.…”

“…Heap (2015) reported that the herbicide selection pressure is continually increasing the resistant biotypes of different weeds. After the first case of P. minor resistance to isoproturon during 1995 in India, P. minor biotypes have developed resistance to ALS-inhibiting herbicide (sulfosulfuron), ACCase-inhibiting herbicides (clodinafop, fenoxaprop and tralkoxydim) and other herbicides with these modes of actions (Chhokar and Malik, 2002;Chhokar and Sharma, 2008;Gherekhloo et al, 2011). Many P. minor biotypes have evolved cross and multiple resistance to herbicides, having different modes of action in different parts of the world (Heap, 2015).…”