Pollen-Mediated Movement of Herbicide Resistance Genes in Lolium rigidum.

Pollen-Mediated Movement of Herbicide Resistance Genes in Lolium rigidum.

Blog Article

The transfer of herbicide resistance genes by pollen is a major concern in cross-pollinated species such as annual ryegrass (Lolium rigidum).A two-year study was conducted in the greenhouse, under favorable conditions for pollination, to generate information on potential maximum cross-pollination.This maximum cross-pollination rate was 56.

1%.A three-year Swim Nappy field trial was also conducted to study the cross-pollination rates in terms of distance and orientation to an herbicide-resistant pollen source.Under field conditions, cross-pollination rates varied from 5.

5% to 11.6% in plants adjacent to the pollen source and decreased with increasing distances (1.5 to 8.

9% at 15 m distance and up to 4.1% at 25 m in the # *Full Quarter horse downwind direction).Environmental conditions influenced the cross-pollination both under greenhouse and field conditions.

Data were fit to an exponential decay model to predict gene flow at increasing distances.This model predicted an average gene flow of 7.1% when the pollen donor and recipient plants were at 0 m distance from each other.

Pollen-mediated gene flow declined by 50% at 16.7 m from the pollen source, yet under downwind conditions gene flow of 5.2% was predicted at 25 m, the farthest distance studied.

Knowledge of cross-pollination rates will be useful for assessing the spread of herbicide resistance genes in L.rigidum and in developing appropriate strategies for its mitigation.