FUTURE PERSPECTIVES OF IN VITRO CULTURE AND PLANT BREEDING
Conventional breeding and plant improvement increasingly become inadequate to keep up with progression and high quality demands. Thus biotechnological techniques are more and more adopted. Initially, biotechnological tools have supported conventional breeding by in vitro culture techniques, comprising micropropagation, speeding up multiplication and improving uniformity. Also, crossing barriers of incompatible plants have been overcome using in vitro methods and embryo rescue techniques in wide hybridization approaches. Marker-assisted breeding is employed for targeted selection of DNA fragments from parental plants in respect to identification of desired characteristics in offspring or among hybrid plants. Phylogeny-assisted breeding and knowledge about genetic relationships support the ability to develop new hybrids. Finally, chemical and radiation induced mutagenesis are established breeding methods known to increase genetic variation in plants. Genetic transformation exploits recombinant DNA technology to introduce new genetic variation. The first commercial cultivars arrived at the marked in the 1990s in the USA. However, the application of genetic transformation in commercial breeding in Europe is still marginal due to investment costs, legal approval and public acceptance. As a result, natural transformation using wild type bacteria and thus avoiding recombinant DNA technology has attracted attention of ornamental plant breeders in Europe. However, during the last decades, several innovative biotechnologies bordering the line between conventional breading and genetic transformation have gained interest. Site-directed mutagenesis of plant genes can modify or inactivate specific gene functions. In cisgenic and intragenic approaches, the transferred DNA originates from the plant species itself or from closely related species. Finally, techniques involving transgenic approaches in the breeding process, but not in the end product can be mentioned, i.e., RNA-dependent DNA methylation which is based on transcriptional gene silencing by methylation of promoter sequences, grafting of a non-genetically modified scion on a GM rootstock, agro-infiltration and reverse breeding. Several of these methods are applicable in various crops, however, the costs for approval are highly dependent on the regulatory status worldwide and whether these technologies are defined as GMO technologies in the future.
Kuligowska, K., Lütken, H., Hegelund , J.N. and Müller, R. (2015). FUTURE PERSPECTIVES OF IN VITRO CULTURE AND PLANT BREEDING. Acta Hortic. 1083, 27-34
biotechnology, genetic modification, mutagenesis, ornamental breeding, transformation