Angelika Senula

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

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.

The Garlic and Shallot Core Collection image database of IPK presenting two vegetatively maintained crops in the Federal ex situ genebank for agricultural and horticultural crops at Gatersleben, Germany

Garlic and shallot are important vegetable and spice plants, garlic is also a medicinal crop widely used throughout the world. Both belong to the genus Allium, which has been a main target of the taxonomical research at the IPK for many years. Therefore, the IPK’s living collection of Allium is one of the world’s largest special collections of this genus with garlic and shallot being essential parts of this collection. Furthermore, they are subject to special activities to preserve the material in vitro and in cryopreservation. Both methods help protecting valuable germplasm from abiotic and biotic threats and reduce the maintenance costs in the long term. At present, the garlic collection maintained at the IPK incorporates germplasm of 509 accessions in total including all safety duplicates not offered for exchange. Of shallot, 114 accessions are present as well. Passport data as well as phenotypic data of 159 accessions of garlic, one of great headed garlic and 16 of shallot are included in the Garlic and Shallot Core Collection Database (GSCC). An additional part of the database is a comprehensive collection of images illustrating morphological characteristics of the accessions. Exploration of the information is supported by a web-based application. The GSCC is available at http://www.ipk-gatersleben.de/databases/gscc.

The changes in the reproductive barrier between hexaploid wheat (Triticum aestivum L.) and rye (Secale cereale L.): different states lead to different fates

AbstractMain conclusionThe changes in the reproductive barrier between hexaploid wheat (Triticum aestivumL.) and rye (Secale cerealeL.) can be induced using in situ embryo rescue of abnormal embryos, yielding stable fertile amphidiploid plants. In intergeneric crosses between hexaploid wheat (Triticum aestivum L.) and rye (Secale cereale L.), postzygotic barriers may occur at different stages of hybrid development. One such mechanism is embryo lethality, which is genetically determined by the interaction and expression of two incompatible genes in wheat (Eml-A1) and rye (Eml-R1). Using in vitro culture methods as stressors, we overcame this hybrid lethality. Normal and abnormal embryos were observed to build embryogenic calli and produce regenerated plantlets in a similar manner. The high regenerative capacity of the abnormal embryos led us to conclude that the reproductive barrier in these intergeneric hybrids may have an epigenetic origin that can be easily overcome by culturing immature embryos via callus induction. After colchicine treatment during callus culture, amphidiploid plants were obtained. However, most of these plants did not produce seeds, due mainly to sterility of the pollen but also of the embryo sacs. These findings demonstrate that hybrid sterility affects both male and female gametophytes in plants obtained from abnormal embryos. The key roles of double fertilization and stress factors in the implementation of the apical meristem formation program in embryos from incompatible intergeneric crosses between hexaploid wheat and rye during in vitro culture are discussed. We also propose a hypothetical model for a wheat–rye lethality system involving differential expression of incompatible wheat Eml-A1 and rye Eml-R1b alleles in an identical genetic background.