Publications

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.

Sequestration of paraquat away from its target site in the chloroplast has been proposed as a mechanism of paraquat resistance. However, no consensus has been reached as to where paraquat is sequestered. This study quantifies paraquat in leaf protoplasts of paraquat resistant (R) and susceptible (S) Lolium rigidum.

Twenty-two amino acid substitutions at seven conserved amino acid residues in the acetohydroxyacid synthase (AHAS) gene have been identified to date that confer target-site resistance to AHAS-inhibiting herbicides in biotypes of field-evolved resistant weed species.

A bio-economic model for Papaver rhoeas designed for dry-land cropping systems in Spain was developed. The model included four seed bank layers to simulate seed movement in the soil profile resulting from tillage, with different emergence rates and seed bank mortalities depending on soil cultivation and burial depth.

Modern herbicides make major contributions to global food production by easily removing weeds and substituting for destructive soil cultivation. However, persistent herbicide selection of huge weed numbers across vast areas can result in the rapid evolution of herbicide resistance.

In a world of more than 6 billion people, humans heavily rely on the dependable cultivation of the global food grain crops: rice, wheat, soybeans, maize (and cotton for fiber). History shows that threats to food production have major repercussions, including famine, war, and civil unrest.