A review of new PCR-based genetic markers and their utility to weed ecology

Several recent molecular developments provide new genetic tools for addressing difficult problems in weed ecology. In this review, we describe some of the techniques and the DNA markers they generate [including amplified fragment length polymorphisms (AFLPs), simple sequence repeats (SSRs) or microsatellites, and intron-polymerase chain reaction (intron-PCR)], contrast their relative advantages and disadvantages, and discuss how they might be used in weed research. As these new markers generally reveal higher levels of variation than other techniques, they promise to improve our understanding of breeding systems, assist in determining the origin(s) of invaders, help to resolve taxonomic boundaries and relationships between closely related taxa and enable the identification of phenotypic linked markers. In addition, compared with other techniques, some of these markers may be more cost-effective, less technically demanding and more reliable. Regardless of the marker adopted, all genetic studies will benefit from careful consideration of experimental design and the formulation of testable hypotheses with practical outcomes.