Glyphosateresistant Italian ryegrass and perennial ryegrass in New Zealand a review

Abstract

In 2013 three populations of perennial ryegrass (Lolium perenne) and two populations of Italian ryegrass (L multiflorum) from five vineyards in New Zealand were confirmed to be resistant to glyphosate The level of resistance in four populations was almost 10fold while one population of perennial ryegrass (Population O) had a level of resistance greater than 30fold Quick tests for confirming the presence of glyphosate in ryegrass plants have been developed Molecular and physiological investigations showed that there was restricted herbicide translocation in all studied populations and Population O also had a modification at Pro106 of the EPSPS enzyme It was also found that the restricted herbicide translocation can be suppressed under cool conditions Further studies also showed that the gene causing restricted herbicide translocation could be readily transferred through pollen and the gene was partially dominant All glyphosate resistant populations were also resistant to glufosinate and three of the populations were also resistant to amitrole