ABSTRACT
Herbicide-resistant crops (HRCs) represent one of the first and most widely publicized applications of plant biotechnology. This chapter discusses the methods used to create HRCs, and describes some more recently developed techniques that may have application in future HRC research. The most straightforward way to obtain HRCs is through selecting from the existing germplasm. Mutagenesis may be combined with selection to enhance the likelihood of recovering herbicide resistant (HR) individuals from large populations. Mutagenesis of pollen may be used to recover a desired phenotype. The advantage of this methodology is that it is easy to mutagenize a large population of haploid pollen grains and, after fertilization, obtain many individuals for screening. Agrobacterium tumefaciens is a Gram-negative soil bacterium that causes tumorous growths, or crown galls, on a wide range of dicotyledonous plants and gymnosperms. Electroporation uses short electrical pulses of high field strength to facilitate DNA uptake by increasing the permeability of cell membranes.
