The literature indicates that glyphosate resistance builds up quite slowly and levels are medium to low. The availability of a reliable and realistic baseline sensitivity is therefore critical to discriminate between susceptible and resistant populations. This study documents the sensitivity to glyphosate of 30 Italian populations of Lolium spp., most of them collected recently in agricultural environments. Our standard susceptible population S-204L, collected more than 10 years ago, was also tested. Sampling sites include feld margins, organic farms (winter cereals), conventional farms (winter cereals, sunfower and perennial crops) and roadsides. Sampling sites cover all major Italian agricultural areas and were chosen on the basis of the absence or scarce application of glyphosate during the last decade. The areas where glyphosate-resistant Lolium spp. had already been reported were avoided. Therefore, the data do not show the status of truly unexposed populations, but rather they represent the "real" status of Italian Lolium spp. sensitivity to glyphosate in agricultural environments. Although morphological traits showed a high variability among and within populations, all were classifed as L. rigidum or L. multiforum or intermediates between the two. A frst outdoor dose-response pot experiment was conducted during spring 2012, and a second is underway to assess the variability of ED , GR , ED , GR curves. Inter-population diferences are being analysed in relation to the feld history or environmental characteristics of the sampling sites. On preliminary data, the lack-of-ft test on both plant survival and fresh weight indicates that it is impossible to simplify the "glyphosate regressions" to a model with a common slope for all populations. In relation to plant fresh weight, GR ranges from 31 ± 8.8 to 98 ± 14.7 and GR from 144 ± 15.7 to 272 ± 26.3. Concerning plant survival, ED varies from 155 ± 5.9 to 260 ± 6.7, while ED ranges from 243 ± 20.8 to 506 ± 79.1.
Variability of Lolium spp. sensitivity to glyphosate
Collavo A;Sattin M
2013
Abstract
The literature indicates that glyphosate resistance builds up quite slowly and levels are medium to low. The availability of a reliable and realistic baseline sensitivity is therefore critical to discriminate between susceptible and resistant populations. This study documents the sensitivity to glyphosate of 30 Italian populations of Lolium spp., most of them collected recently in agricultural environments. Our standard susceptible population S-204L, collected more than 10 years ago, was also tested. Sampling sites include feld margins, organic farms (winter cereals), conventional farms (winter cereals, sunfower and perennial crops) and roadsides. Sampling sites cover all major Italian agricultural areas and were chosen on the basis of the absence or scarce application of glyphosate during the last decade. The areas where glyphosate-resistant Lolium spp. had already been reported were avoided. Therefore, the data do not show the status of truly unexposed populations, but rather they represent the "real" status of Italian Lolium spp. sensitivity to glyphosate in agricultural environments. Although morphological traits showed a high variability among and within populations, all were classifed as L. rigidum or L. multiforum or intermediates between the two. A frst outdoor dose-response pot experiment was conducted during spring 2012, and a second is underway to assess the variability of ED , GR , ED , GR curves. Inter-population diferences are being analysed in relation to the feld history or environmental characteristics of the sampling sites. On preliminary data, the lack-of-ft test on both plant survival and fresh weight indicates that it is impossible to simplify the "glyphosate regressions" to a model with a common slope for all populations. In relation to plant fresh weight, GR ranges from 31 ± 8.8 to 98 ± 14.7 and GR from 144 ± 15.7 to 272 ± 26.3. Concerning plant survival, ED varies from 155 ± 5.9 to 260 ± 6.7, while ED ranges from 243 ± 20.8 to 506 ± 79.1.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
