Abstract Detail

Molecular Ecology

Hoffberg, Sandra [1], Eaton, Deren [2].

The phylogenetic context of herbicide resistance in Amaranthus shows minimal spread through introgression.

Modern agriculture practices that rely heavily on herbicides can promote rapid evolution of herbicide resistance in weedy plant species. In recent decades many species in the genus Amaranthus (pigweed, amaranth, or waterhemp) have evolved resistance to multiple common herbicides and currently cause significant agricultural losses in the United States each year. Hybridization has been reported to spread herbicide resistance between species, but it is unclear how important introgressive hybridization is compared to repeated independent evolution of the same trait. The history of how these adaptations arose in multiple species provides a powerful way to study adaptation on large geographic and temporal scales and can help predict the future spread of herbicide resistance. To assess the degree of introgressive hybridization versus independent evolution of resistance, we compared contemporary samples from across the United States and accessions from the National Plant Germplasm System which were collected before the widespread use of herbicides led to strong selection for herbicide resistance. We reconstructed a phylogeny including 34 Amaranthus species using genomic data resulting from 3RAD and RADcap libraries. Despite comparing obligately outcrossing species, we find that introgression is not a major driver of herbicide resistance, but possibly important on small spatial scales.

1 - Columbia University, Ecology, Evolution, Environmental Biology, 1200 Amsterdam Ave, Schermerhorn Ext, 10th floor, New York, NY, 10027, USA
2 - Columbia University, Ecology, Evolution, And Environmental Biology, 1200 Amsterdam Ave. , Schermerhorn Ext. Office 1007, New York, NY, 10027, United States

herbicide resistance

Presentation Type: Oral Paper
Abstract ID:749
Candidate for Awards:None

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