Use of biotechnology for preserving rare fruit germplasm

Abstract

The application of recent biotechnological tools for conservation of rare fruit species from developing countries, including in vitro and hydroponic culture protocols, improved propagation techniques and molecular marker application, is described. Promising propagation methods include forcing germination of seeds, in-vitro protocols well adapted to these rare fruit species that allow the introduction, micropropagation and rooting of plant material, and developing hydroponic culture protocols that allow the early propagation of high-risk genotypes. In addition, the growth of seedlings in controlled environmental conditions in greenhouse and cold chamber provides a useful strategy for obtaining vigorously growing plants from seeds year round. A standard karyotyping protocol has been described working in several species as preliminary tool to start molecular (DNA) studies. In addition, different protocols for DNA isolation and quantification have been assayed in these rare fruit species. Molecular markers based on PCR amplification of the DNA have also become an essential tool for the characterization and conservation of these species. Regarding this PCR amplification of the DNA, two main strategies, RAPD (if the DNA sequence is unknown) and SSR markers (if the DNA sequence is known), have been assayed. These markers have been applied in the genetic characterization of this germplasm, the establishment of genetic relationships between cultivars and species, and the future construction of genetic maps of these rare fruit species. Additional advantages encouraging the utilization of these new technologies in breeding programs include the high levels of synteny between genomes of related species, and a well-established international network of cooperation among researchers.