Genetic pollution: concepts, concerns and transgenic crops

Genetic pollution implies the loss of identity of wild plant species as a r esult of transfer of genes from crop plants, with engineered fitness genes causing special concern. However, significant reproductive barriers exist b etween most wild species and crop plants. Gene flow is expected to have its greatest effect on weed species which are closely related to crop plants, taxonomically, ecologically and in their reproductive biology. Such plants may already have a long history of gene exchange with their crop relatives.