ABSTRACT
Not all applications of molecular biology are commercial. For example, there is a necessity to be able to taxonomically classify weeds, as there are differences in selective control among related and hard to distinguish weeds, as epitomized by weeds of the genus Amaranthus.933 Molecular taxo nomy has been of great assistance and has often provided the decisive data in many cases on whether two similar Amaranthus species were actu ally one, or were separate, or were hybrids, depriving classical taxonomists of their endless battles. This has been done recently with the taxonomi cally challenging Amaranthus spp., which also have a propensity to cross among themselves.198,806,1521 Knowing relatedness will be required for assessing the risks of crop gene introgression into weeds, and has been used to trace whether an Amaranthus biotype evolved resistance by intro gression, vs by its own internal mutation.1522
