Potato breeding and a role for GM technology

Potato breeding started around the beginning of the 19th century but its complex tetraploid genetics means that targeted breeding is a time-consuming exercise. Comparatively speaking, potato has a narrow genetic base, which, at least in part, contributes to slower progress in crop improvement than with other major crop species. Attempts to introgress genes from wild relatives has met with some success for disease resistance traits but undesirable side effects from hybridisation events mean that periods of ca. 12 to 15 years have been required for cultivar development. Since back-crossing to remove undesirable effects is not an easy option for potato, the approach of improving existing cultivars using gene transfer or genetic engineering technology has been an attractive proposition. Realistically, this approach is not meant to replace the role of the plant breeder, but to complement it by providing additional tools to modify potato genomes for environmental and commercial benefit. From an environmental perspective GM potato poses few risks as pollen movement is extremely limited (separation distances for experimental release of nine metres are acceptable in the UK) and there are no wild relatives with which cultivated potato can outcross.