Ensuring and exploiting genetic diversity in rice Jennifer Spindel and Susan McCouch, Cornell University, USA
Genetic diversity is the basis for all advances in breeding and genetic improvement and represents an insurance policy for dealing with disaster. To contribute to the goal of achieving sustainable rice cultivation for the future, applied plant breeding programmes must continuously balance efforts to develop and refine elite gene pools in which favourable alleles are painstakingly accumulated over time, with the need to access novel, potentially disruptive, variation from unadapted or exotic sources for times of adversity. To dynamically manage both streams in a productive breeding programme requires a multi-tiered approach. When imposing selection in a relatively stable environment and in keeping with well-defined consumer preferences, a breeder can meet both grower and consumer demands by working within an elite gene pool. As a long-term strategy, however, this approach can have the unintended consequence of severely narrowing the genetic base, leaving breeders without access to the range of genetic variation they need to respond to new challenges as they arise.