The most prominent QTLs for mean disease severity in wound-inoculated potato tubers with bacteria Dickeya solani explained 22.4% and 16.5% of the phenotypic variance, and were identified on potato ch...

Potato relatives adapted to many different habitats are promising sources of desirable agricultural traits for potato breeding. Wild potato relatives are preserved in different collections around the world, and their detailed description is key to their exploitation in practice. We described 29 seed accessions of 26 Solanum species originating from the VIR potato collection (Institute of Plant Industry – VIR, Saint Petersburg, Russia) and preserved in Poland. The description included resistance to Phytophthora infestans, tuber flesh colour, enzymatic discolouration and tuber dormancy (sprouting). Up to 13 genotypes were evaluated per accession. The evaluation was repeated in three years for each trait. Two P. infestans isolates were used in late blight resistance tests. Amongst all the tested accessions, five were resistant to both P. infestans isolates, including genotype 13_A2. Twenty-one accessions had white tuber flesh, and 13 accessions showed a lack of or weak enzymatic discolouration. Additionally, we found accessions that were whiter than the standard white-fleshed Polish potato cultivar Irys. In our material, we observed a large variation in the length of the sprouts after storage, indicating differences in the dormancy period length. Four accessions showed a lack of sprouting after 28 weeks of storage at 5–6 °C. The tested material is preserved as in vitro plants in the National Centre for Plant Genetic Resources: Polish Genebank (IHAR-PIB, Radzików, Poland), which will facilitate their use in breeding programs.

Phytophthora infestans (Mont.) de Bary is an oomycete plant pathogen that causes late blight in potato (Solanum tuberosum L.) and tomato (Solanum lycopersicum L.). This review documents the population structure of P. infestans in northern and eastern Europe, and aims to explain the differences between populations of P. infestans in this region and in western Europe. Populations of P. infestans are influenced by many factors, e.g., migrations related to the movement of potato seed tubers, possibility of sexual reproduction, changes in climate, and agricultural management practices. All the presented factors may have a significant impact on the P. infestans population structure. The knowledge on P. infestans populations varies strongly depending on country and time, even within the rather intensively studied region of eastern and northern Europe. Our review indicates some knowledge gaps, such as a lack of data for some countries and gaps in some years in population monitoring. This indicates the need to continue the monitoring of P. infestans populations.

Key message Using a diploid potato diversity panel of 246 breeding lines, a genotyping-by-sequencing and a GWAS approach, we mapped QTL for ten traits important to potato breeders, including two previously unmapped traits: boiled tuber taste and pollen fertility. Abstract Potato breeding at the diploid level has a long history and has gained new impetus recently, when F1 hybrid breeding was made possible with the discovery of a dominant gene for self-compatibility. Our study deploys a unique diploid diversity panel with a broadened cultivated potato gene pool obtained as a result of introgressing valuable traits from wild potato relatives into the Solanum tuberosum background. Using historical phenotyping data collected between 1979 and 2017 for 246 diploid potato clones and high-density genotyping-by-sequencing, we mapped quantitative trait loci (QTL) for tuber yield, mean tuber weight, tuber shape and regularity, tuber eye depth, purple tuber skin colour, flesh colour, tuber starch content, boiled tuber taste (flavour) and pollen fertility. We found some QTL located in genomic regions described in earlier studies, e.g. the QTL for the tuber flesh colour on chromosome 3 overlapping with the location of beta-carotene hydroxylase gene. We identified novel QTL for mean tuber weight on chromosomes 8, 9 and 11 and for purple tuber skin colour on chromosomes 6, 7 and 8. QTL for boiled tuber taste and pollen fertility estimated by Lactofuchsin staining have not been mapped before. We found two regions on chromosome 10 affecting the boiled tuber taste, and QTL on chromosomes 2, 4, 5, 6, 9, and 12 for pollen fertility. Considering the increased interest in diploid hybrid potato breeding, the results presented here hold greater relevance and provide novel targets for potato breeding and research at the diploid level.

Background Potato virus Y (PVY) is among the economically most damaging viral pathogen in production of potato (Solanum tuberosum) worldwide. The gene Rysto derived from the wild potato relative Solan...