Multiple resistance of Papaver rhoeas L. to 2,4‐D and acetolactate synthase inhibitors in four European countries

Abstract

SummaryThe issue of cross‐ or multiple resistance to acetolactate synthase (ALS) inhibitors and the auxinic herbicide 2,4‐D was investigated in Papaver rhoeas L., a common and troublesome weed in winter cereals, in a broad‐scale study across four European countries. A combination of herbicide sensitivity bioassays and molecular assays targeting mutations involved in resistance was conducted on 27 populations of P. rhoeas originating from Greece (9), Italy (5), France (10) and Spain (3). Plants resistant to the field rate of 2,4‐D were observed in 25 of the 27 populations assayed, in frequencies ranging from 5% to 85%. Plants resistant to ALS‐inhibiting herbicides (sulfonylureas) were present in 24 of the 27 populations, in frequencies ranging from 4% to 100%. Plants resistant to 2,4‐D co‐occurred with plants resistant to sulfonylureas in 23 populations. In four of these, the probability of presence of plants with cross‐ or multiple resistance to 2,4‐D and sulfonylureas was higher than 0.5. ALS genotyping of plants from the field populations or of their progenies, identified ALS alleles carrying a mutation at codon Pro197 or Trp574 in 2,4‐D‐sensitive and in 2,4‐D‐resistant plants. The latter case confirmed multiple resistance to 2,4‐D and ALS inhibitors at the level of individual plants in all four countries investigated. This study is the first to identify individual plants with multiple resistance in P. rhoeas, an attribute rarely assessed in other weed species, but one with significant implications in designing chemical control strategies.

Herbicide Resistance and Management Options of Papaver rhoeas L. and Centaurea cyanus L. in Europe: A Review

“…Both corn poppy and cornflower are insect pollinated. However, corn poppy is highly self-compatible; it exhibits significant genetic variation and a high phenotypic plasticity, which cause variable coloration of the crown petals and variable leaf shapes [49,50]. Genetic diversity in corn poppy populations indicates its high potential for adaptation to changing environmental conditions and its ability to settle new habitats [51,52].…”

“…2,4-D is one of the most widely used herbicides and has been available on the market since 1945 [82]. Significant also is a selection of corn poppy biotypes with multiple resistance to different herbicides of the sulfonylurea group and also 2,4-D or MCPA [11,50,83]. Kotoula-Syka et al [84] identified a poppy biotype from Bafra (north Greece) that was highly resistant to chlorsulfuron, but also cross-resistant to tribenuron, triasulfuron, thifensulfuron and imazethapyr.…”

“…In contrast, of the 71 plants classified as florasulam-resistant, 63.4% of plants were moderately resistant [92]. Kati et al [50] studied the frequency of resistant poppy biotypes in populations from Greece, Italy, Spain and France. Resistance to ALS inhibitors was detected in 24 of the 27 field populations assayed.…”

“…Overall, plants resistant to ALS inhibitors were observed with plants resistant to 2,4-D in seven populations from Greece, five from Italy, eight from France and three from Spain. The study of Kati et al [50] demonstrated for the first time the occurrence of multiple resistance to ALS inhibitors and to auxinic herbicides in individual corn poppy plants in these countries.…”

Resistance Mechanisms to 2,4-D in Six Different Dicotyledonous Weeds Around the World

“…It is expected that the number of cases will increase trough the next years due to both new uses of 2,4-D enabled by the introduction of 2,4-D R crops, and also its incremental use due to greater dependence on SAH in response to the emergence of resistance to other herbicides [23]. Among many countries, very important new weeds R to 2,4-D have been cited: Amaranthus hybridus from Argentina [24] and Parthenium hysterophorus from Cuba [25], in which enhanced metabolism seems to be involved, and Papaver rhoeas is now spreading in France and Italy [26]. Other cases have been reported but not yet investigated, including Conyza canadensis from Hungary and C. sumatrensis from France, both found in vineyards, and Hirschfeldia incana from Argentina in winter cereals, reported by the co-author Dr. Vigna [11].…”