Genetic Erosion Under Modern Plant Breeding: Case Studies in Canadian Crop Gene Pools

There is long-standing concern that modern plant breeding reduces crop genetic diversity. Such reduction may have consequences both for the vulnerability of crops to biotic and abiotic stress. To understand the impact of plant breeding on diversity, we conducted a series of genetic diversity analyses from 1999 to 2009 on existing Canadian gene pools of flax, oat, wheat, soybean, potato and canola. Here we summarize these analyses, highlight major findings, and discuss related issues. These gene pools displayed variable patterns and degrees of genetic diversity decline over the past 100 years of Canadian breeding efforts. Significant allelic loss and genetic shift were found in the wheat and oat gene pools. Such diversity declines underline the need for continuous efforts in conservation of improved crop germplasm and in the diversification of plant breeding materials for sustainable breeding programs.