Characterization of high anthocyanin-producing tetraploid potato cultivars selected for breeding using morphological traits and microsatellite markers

Purple- and red-fleshed potato cultivars constitute a great source of phenolic compounds, which may promote human health. Since the characterization of potato germplasm is a key step during the breeding process, the classification of high anthocyanin-producing tetraploid genotypes may facilitate the incorporation of phenolic-related traits in a potato breeding programme. A set of 18 high anthocyanin-producing underutilized tetraploid cultivars, which have been previously classified in terms of phytochemical content, have been characterized by both microsatellite markers (simple sequence repeat, SSR) and morphological descriptors. A wide genetic variability was found using 11 highly discriminatory SSR markers. The collection also displayed a large amount of variation for most morphological traits. The neighbour-joining trees defined by SSR markers and morphological descriptors revealed genetic and phenotypic relatedness of the potato genotypes. Despite the complexity of tetrasomic inheritance, high anthocyanin-producing tetraploid cultivars should be considered for potato breeding since they are adapted to long-day conditions and do not present undesirable characteristics that are found in native accessions or landraces.

Assessment of genetic diversity and relatedness in the Latvian potato genetic resources collection by DArT genotyping

Potato (Solanum tuberosumL.) has been cultivated in Latvia since the 17th century, and formal breeding programmes have been established since the start of the 20th century. The Latvian potato genetic resource collection consists of 83 accessions of Latvian origin, including landraces, old cultivars released starting from the 1930's, modern cultivars and breeding material. These are maintained in field andin vitrocollections. Pedigree information about the potato cultivars is often limited, and the use of hybrids of local cultivars as parents is common in the Latvian potato breeding programme. Ninety-four Latvian potato varieties and breeding lines and some commonly used foreign accessions were genotyped with the potato DNA diversity array technology. Analysis of the Latvian potato genetic resources collection revealed that the amount of genetic diversity has increased in the modern cultivars in comparison with the old cultivars.

Development of Potato Varieties in Latvia

The first potato varieties that reached the territory of Latvia were empirically selected clones from genetically diverse material brought from South America to Europe. In the 19th century, when agricultural production rapidly developed, the demand for high yielding potato varieties suitable to local growing conditions increased. Therefore, potato variety evaluation trials were set up. Scientifically- based potato breeding in Latvia was launched by P. Knappe. The potato breeding programme in Priekuïi Plant Breeding Station was started in 1931, and has still continued. Several breeding methods were used by potato breeders Ç. Knape, V. Gaujers, G. Bebre and others in Priekuïi. Potato breeding for short periods was carried out in several other places in Latvia: Stende, Carnikava, and Lejaskurzeme. The method of elimination of diseases in potato seed material and high quality seed material production was implemented in Priekuïi. More than 60 potato varieties have been created in Latvia, some of them were and still are in demand in agricultural production.

The response of potato (Solanum tuberosum L) to the fungus Rhizoctonia solani

Rhizoctonia solani is a soilborne fungal pathogen of many economically important crops Thirteen closely related anastomosis groups (AGs) of this pathogen have been identified each of which affects different plant species Previous studies have suggested that R solani AG3 is the main cause of disease in potato Rhizoctonia solani infection of potato plants can result in stem canker and tubers with black scurf Affected plants give a reduced yield while affected tubers are considered to have reduced quality resulting in economic loss The current study investigated the response of different potato cultivars and lines to R solani AG3 Thirtytwo potato cultivars/lines many actively used in the Plant Food Research potato breeding programme were screened in a shadehouse pot trial The trial was laid out in an adapted resolvable block design to ensure uniform exposure to environmental factors Each cultivar had six replicates four with and two without AG3 inoculum Plants were grown to maturity and the resulting tubers were assessed for disease (black scurf) Preliminary results show that none of the lines/cultivars tested were resistant but degrees of susceptibility varied In this experiment stem canker was not observed in any of the lines/cultivars

Evaluation of potato cultivars and breeding lines for susceptibility to tuber soft rot induced by Erwinia carotovora subsp atroseptica

Bacterial soft rot of potato tubers in storage is an economically important postharvest disease worldwide Disease control measures include reduction of tuber damage at harvest provision of suitable storage conditions and breeding of resistant cultivars Tubers of 18 potato cultivars and breeding lines were assessed for susceptibility to infection by Erwinia carotovora subsp atroseptica (Eca) over three maincrop seasons between 2003 and 2007 Susceptibility to Ecainduced soft rot was determined by measuring the weight of rotted tissue in anaerobically incubated whole tubers 7 days after inoculation with Eca Potato lines differed in susceptibility to soft rot by a factor of >37 (weight of rotted tissue) Cultivars Crop 28 Ilam Hardy and 30975 were highly susceptible and 065/27 Crop 15 and Crop 16 were least susceptible to Ecainduced soft rot As a consequence of these trials several of these lines are now being used in Plant Food Researchs potato breeding programme in order to develop cultivars with lower soft rot susceptibility than cultivars currently grown

Investigation of resistance specificity amongst fifteen wild Solanum species to a range of Globodera pallida and G. rostochiensis populations

The breadth of resistance to populations of the potato cyst nematodes, Globodera pallida and G. rostochiensis, which differed both in virulence level and country of origin, was investigated in 15 wild Solanum species. A range of responses to the populations was noted, with significant interactions observed between the potato genotypes and Globodera populations assayed. Of the 15 wild Solanum species, seven appeared to be potentially valuable sources of wide spectrum resistance with low multiplication rates with all populations recorded. The inclusion of these species into a potato breeding programme is justified by this study.