Genetic identity of three mint accessions stored by different conservation procedures: field collection, in vitro and cryopreservation

摘要

At the genebank of IPK (Leibniz Institute of Plant Genetics and Crop Plant Research) in Gatersleben, Germany, three long-term conservation methods (field genebank, in vitro slow-growth and cryopreservation) are used for mint germplasm. The plant material of the field genebank was the source to establish the slow-growth in vitro culture collection, from which the cryopreserved collection was set up, using a droplet-vitrification protocol. The genetic identity of 161 samples of three mint accessions (MEN 198, MEN 166 and MEN 186), stored for several years using those three methods, was studied using RAPD markers. Accession 'MEN 198' was the only one with a unique RAPD fragment pattern for all its samples, independently of the conservation procedure employed. The field collections of accessions 'MEN 166' and 'MEN 186' were made up of different genotypes. None of the genotypes detected in the plots of these accessions was represented in the in vitro and cryopreserved samples analyzed, which showed a unique genotype for each accession. From this work we conclude that, for an appropriate management of a germplasm collection of vegetatively propagated species, the determination of the genetic composition of the donor material and a periodical assessment of the preserved material should be carried out.