Population Genetic Structure in Glyphosate-Resistant and -Susceptible Palmer Amaranth () Populations Using Genotyping-by-sequencing (GBS).

Palmer amaranth () is a major weed in United States cotton and soybean production systems. Originally native to the Southwest, the species has spread throughout the country. In 2004 a population of was identified with resistance to glyphosate, a herbicide heavily relied on in modern no-tillage and transgenic glyphosate-resistant (GR) crop systems.

Survey of the genomic landscape surrounding the 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) gene in glyphosate-resistant Amaranthus palmeri from geographically distant populations in the USA.

Background: Glyphosate resistance in Amaranthus palmeri, one of the most prevalent herbicide-resistant weeds in the USA, is attributable to amplification and increased expression of the gene encoding the target site of glyphosate, 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS). The EPSPS gene and the surrounding 287 kilobases (kb) of amplified sequence are unique to glyphosate-resistant plants and termed the EPSPS cassette. It has only been sequenced in one A.