1/3/12, 11:36

Reduced sensitivity to paraquat evolves under selection with low glyphosate doses in Lolium rigidum

En el presente artículo se describe que una población susceptible a glifosato de ryegrass evolucionó hacia una resistencia moderada al herbicida con tratamientos de bajas dosis durante tres generaciones sucesivas. Además se informa que las progenies seleccionadas con glifosato evolucionaron también resistentes a paraquat.

Roberto Busi & Stephen B. Ponles

Agronomy Sust. Developm., 31: 525–531 (2011)

 

This is the first report of low-dose glyphosate selection causing a shift towards paraquat resistance. Herbicide resistance in weed species is a serious threat to world agriculture. We report rapid resistance evolution in the genetically variable cross-pollinated grass weed Lolium rigidum when recurrently selected with low doses. Results show that an herbicide-susceptible L. rigidum population selected over three generations with below-label doses of glyphosate exhibited not only glyphosate resistance evolution but also a progressive and concomitant shift in sensitivity to the structurally unrelated herbicide paraquat. Thus, reduced paraquat sensitivity was a consequence of recurrent selection with glyphosate at low doses. In the three-time glyphosate-selected progeny, the estimated paraquat dose to cause 50% mortality (LD50) was 4-fold greater than for the unselected susceptible parent. Studying the evolutionary outcomes of below-label herbicide dose selection can help prevent genetic changes in weed populations and sustain the efficacy of herbicides widely used in world agriculture.