WENDEL, JONATHAN F. Department of Botany, Iowa State University, Ames, IA 50011. - Evolution of crop plants: models, mechanisms, and implications.
Of approximately 300,000 species of flowering plants, humankind is fed
and clothed by only several dozen major crops. These crops were
largely developed by aboriginal domesticators in ancient times from
often obscure origins. Interdisciplinary studies combining the tools
of evolutionary and molecular biology have provided novel insights
into the origins of modern crop species, including identification of
wild progenitors and patterns of genetic diversity. Plant
domestication has been characterized by sequential genetic
bottlenecks, whereby relatively large gene pools were repeatedly
winnowed during selection of modern cultivars and breeding
populations. Crop improvement has been accompanied by dramatic
morphological alterations, thereby providing model systems for
analyses of the evolutionary and developmental genetics underlying
morphological innovation in nature. These analyses are facilitated by
genomic and proteomic approaches. Because many important crops,
including wheat, maize, and cotton, are polyploids, these species
provide model organismal frameworks for analyzing the fate of
duplicated genes and genomes following polyploid formation. Polyploidy
is associated with novel genomic interactions and molecular genetic
mechanisms, and is suggested to have opened up new avenues for
agronomic improvement.
Key words: cotton, genetic diversity, maize, morphological evolution, Plant domestication, polyploidy