AWRI Thum

Herbicide resistance

My lab currently has several projects focusing on herbicide resistance in invasive milfoil populations.  Specifically, we are determining whether hybridization is associated with decreased response to two commonly used aquatic herbicides with different modes of action (one is a carotenoid synthesis inhibitor, the other is a growth regulator).

Herbicide resistance has become a major field of study in weed science.  However, to my knowledge there are no known cases where herbicide resistance has been shown to evolve via hybridization.  There are (at least) two reasons to think that hybridization might facilitate the evolution of herbicide resistance.  First, hybridization can lead to heterosis (higher fitness in hybrids relative to parents), and heterotic plants may simply be harder to kill because they are healthier.  In other words, hybrids may simply require higher doses of herbicides relative to parental genotypes.  Second, hybridization may provide greater amounts of variation for populations to respond to local selection pressures, such as herbicides.

Ongoing projects in this area include experimental comparisons of herbicide response by hybrid and parental lineages, and molecular genetic characterization of amino acid mutations and expression differences for a candidate gene involved in carotenoid biosynthesis.

Herbicide resistance is a rapidly developing area of research in my laboratory, and opportunities for students to develop projects are abundant.  Stay tuned for more results....

Page last modified January 27, 2012