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United States Department of Agriculture

Agricultural Research Service

Title: Genetic Vulnerability and Erosion in Annual Crops

Author
item Bretting, Peter

Submitted to: Congress on In Vitro Biology
Publication Type: Abstract Only
Publication Acceptance Date: March 15, 1997
Publication Date: N/A

Technical Abstract: The genetic effects of human selection on annual, sexually and asexually-propagated crops have been extreme: transformation from wild types into weedy semi-domesticates and/or folk varieties, worldwide dispersal and subsequent adaptation to novel environments and, during this century, cultivation of monocultures of crop varieties developed by scientific breeding programs (e.g., the Green Revolution). Genetic vulnerability and erosion in the genepools of wild plants and traditional crop cultivars may result from severe reductions in populational sizes, and from loss or deterioration of habitats, traditional human cultures and agroecosystems, and germplasm collections. Modern crop improvement may lead to genetic erosion in crop genepools when extirpated varieties and genes are unavailable for increasing crop yields via genetic gain, and for tailoring new cultivars to meet societal needs. Genetic vulnerability may result from excessively homogeneous cultivars in farmers' fields, and subsequent susceptibility to biotic (pests, diseases) and/or abiotic (weather, soil) stresses. To counteract genetic uniformity in farmers' fields, new genetically divergent cultivars must be developed continually. To do so, breeders require access to extensive genepools (including wild species) safeguarded from genetic erosion in genebanks or in reserves. If forest production in the future increasingly resembles crop production with respect to cultivation of relatively few, homogeneous genotypes, it may be accompanied by genetic erosion and vulnerability that may require remedies resembling those instituted to safeguard crop genepools.

Last Modified: 9/10/2014
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