Search

As part of a comprehensive program for registering and preserving the gene pool of Russian varieties in the VIR genebank, initiated at the N.I. Vavilov All-Russian Institute of Plant Genetic Resources, nomenclatural standards were assigned to potato cultivars ‘Alâska’, ‘Argo’, ‘Bravo’, ‘Irbitskij’, ‘Legenda’, ‘Lûks’, ‘Terra’, and ‘Šah’, and a voucher specimen was prepared for pre-cultivar ‘Bagira’. All of them were bred at the Ural Federal Agrarian Research Centre (Ural Branch of the Russian Academy of Sciences). Nomenclatural standards of these cultivars are preserved in the Nomenclatural standard collection at the Herbarium of cultivated plants and their wild relatives and weeds (VIR Herbarium, WIR). For each of them, a genetic passport was developed using DNA preparations isolated from plant material donated by the cultivar author to the VIR herbarium. The genetic passport, which includes information on the allelic composition of eight chromosome-specific microsatellite loci, is supplemented by the molecular screening data with markers of 11 R-genes for resistance to pests, as well as the data on the types of cytoplasm. The author of cultivars also supplied VIR with samples of virus-free in vitro plants. Microplants of eight Ural cultivars and one pre-cultivar were genotyped using the same SSR markers and included in the VIR in vitro collection, and then in the cryopreservation program. Most of the accessions were characterized by a relatively high, above 39%, level of post-cryogenic regeneration. Frozen explants of the genotyped Ural cultivars (‘Alâska’, ‘Argo’, ‘Legenda’, ‘Terra’, and ‘Šah’) and pre-cultivar ‘Bagira’ were placed for long-term storage in the VIR Cryobank.

In accordance with the International Code of Nomenclature for Cultivated Plants, five nomenclatural standards have been prepared for five potato сultivars1 ‘Alena’, ‘Bylina Sibiri’, ‘Večernij Omsk’, ‘Triumf’, ‘Hozâûška’ bred by the Omsk Agrarian Research Center. Genetic passports were issued to these five cultivars according to the new integrated strategy developed at VIR. According to the strategy, the plant material donated by the author of the cultivars to the VIR Herbarium was used for molecular genotyping. Genetic passports included data of allelic composition of eight chromosome-specific microsatellite loci, markers of different types of organelle DNA, as well as data about diagnostic fragments of 15 markers of 11 R-genes conferring resistance to the most dangerous diseases and pests of potato, namely late blight, nematodes, potato X and Y viruses. Data from genetic passports of five Omsk cultivars were compared to the results of genotyping samples of the same cultivars obtained from different sources. Based on the analysis of pedigrees and genetic passports of these five cultivars, we established the origin of their resistance to harmful organisms.

The N.I. Vavilov All-Russian Institute of Plant Genetic Resources (VIR) is developing new approaches to documentation of national cultivars, taking into account recommendations of the International Code of Nomenclature for Cultivated Plants in parallel with methods of genetic certification. The nomenclatural standard of a particular cultivar represented by a herbarium specimen can be used as a reference for verifying authenticity and uniformity of cultivar specimens obtained from various sources. The verification requires fast and reliable methods for cultivar genotyping. This paper presents protocols for modified methods of DNA extraction, PCR-analysis and SSR-genotyping, which allow potato cultivars identification without the use of expensive reagent kits. A set of ten chromosome-specific microsatellite markers was used to study polymorphisms in 66 modern Russian potato cultivars, as well as in 11 pre-cultivars and breeding clones, represented by nomenclatural standards and voucher specimens, respectively. This subset of 77 specimens has demonstrated a high level of polymorphism in ten studied microsatellite loci. The SSR analysis identified 73 alleles; 7.3 alleles per locus were observed on average, the number of which varied from 3 (STG0025 locus) to 11 (locus StI046). The PIC values varied from 0.544 (STG0025 locus) to 0.836 (StI046 locus). The alleles, unique for this subset, were found at six studied loci. The high level of polymorphism at the SSR loci made it possible to unambiguously identify almost every cultivar, with the exception of the expected coincidence of microsatellite profiles of two cultivars, which are somaclonal variants. Using an optimized set of eight microsatellite markers, the genetic relationships of modern Russian potato cultivars were studied.