Table 1. New plant-breeding techniques.
| Technique | Function | GM-free end product? |
|---|---|---|
| Genetic manipulation as a tool to facilitate breeding | ||
| Virus-induced gene silencing | Transient silencing of specific genes for functional analysis. | Yes |
| Agro-infiltration | Uses Agrobacterium to achieve temporary, local expression of genes that are foreign to the species, for example to test the ability of a plant to resist pathogen attack. Agrobacterium-free cuttings or seeds are used for further development. | Yes |
| Reverse breeding | To produce improved F1-hybrid varieties that are free from introduced genes. | Yes |
| Accelerated breeding | Genetic modification is used to speed up breeding by inducing early flowering. | Yes |
| Grafting of non-GM material to GM material | ||
| Chimeric plants | For example, non-GM plant grafted onto a GM rootstock to improve cultivation characteristics. The harvested part of the plant will not contain foreign DNA, although RNA transcripts and metabolites can pass into the harvestable parts of the plant. | Yes |
| Genetic modification using material from the same species or a sexually compatible species | ||
| Cis-genesis | Uses DNA from the same species or a cross-compatible species. The regulation of gene expression is unaltered from the native state. The product could be generated by conventional breeding. | No |
| Intra-genesis | Similar to cis-genesis, but incorporating new combinations of regulatory and coding sequences, normally for silencing genes. | No |
| Genetic manipulation as a tool for inducing specific mutations | ||
| Oligonucleotide-mediated mutation | Causes site-directed mutations within genes. Used to knock out or adapt gene function. Plants are similar to those obtained through traditional mutagenesis-based breeding. | Yes |
| Zinc-finger nuclease | Zinc fingers are attached to a protein that cuts the DNA between the recognition sites matched by the fingers. The cell repairs the DNA and thereby knocks out the gene. If a new gene is inserted at the same time as the zinc fingers, the new gene can be inserted at the break site. Dow Agrosciences has licensed this technology for creating new crop plants. | Yes |
Based on Schaart & Visser (2009). GM, genetically modified.