Genetic transformation in conifers
- Download PDF (1115074)
- This publication is available only online.
In: Jain, S.M.; Gupta, P.K., eds. Somatic embryogenesis in woody plants. Vol. 5. The Netherlands: Kluwer Academic Publishers: 291-312.
Several attempts at the genetic improvement of tree species have been made, but in comparison with crop plants the efforts as well as the results have been rather limited. The most commonly used approaches have involved selection of superior genotypes from natural outbred populations, mutations, and intra- and inter-specific hybridization under controlled conditions. While the conventional methods have proven remarkably successful in yielding improved genotypes that could be stabilized by back crossing, the techniques of cloning, marker-aided selection, and genetic engineering when integrated with the conventional breeding programs, will dramatically improve genetic gains. Conventional methods of genetic improvement involve a recombination of pre-existing gene pools within a limited range of sexually compatible taxa. The process of backcrossing and selection takes several generations before a desired set of genes can be transferred to a selected species. Genetic manipulation through recombinant DNA permits us to cross the barriers of incompatibility, not only among species and genera but also among kingdoms. Genetic engineering provides new tools for mixing genetic information in plants from a vast pool of existing genes as well as genes designed by human intervention, i.e. synthetic gene sequences. Furthermore, undesirable genes in the plant genome can be selectively silenced in the target tissues by the antisense approach (Bourque, 1995; Lee and Douglas, 1997). Site-specific mutagenesis, homologous recombination, and the use of specific promoters provide a precise means of controlling specific gene expression and its manipulation to achieve optimal genetic improvements.
Minocha, S.C.; Minocha, R. 1999. Genetic transformation in conifers. In: Jain, S.M.; Gupta, P.K., eds. Somatic embryogenesis in woody plants. Vol. 5. The Netherlands: Kluwer Academic Publishers: 291-312.