Pedigree TH E WOR LD OF B reeders use parental material as they call it. A variety or a genotype i.e. a not or not yet named clone may be high yielding but does not have the good shape. Pollen of the high yielding variety is then used to fertilize flowers of the well shaped tubers delivering plant and in the progeny the search for high yielding genotypes with well shaped tubers can start. Pedigree information therefore is useful for breeders. Of course nowadays breeders have genomics available that yields very much information, but pedigree analysis is still a very useful tool to assess relatedness – to avoid too narrow genetic bases – and to know about heritability of traits such as wart resistance for instance. Joint gene mapping and pedigree analysis yields information for breeders to genetically (where on which chromosome is the gene located?) distinguish between genotypes that phenotypically cannot be distinguished. Knowing better the pedigree of wart resistance reveals an enormous redundancy in the different varieties used to characterize the pathotype so its determination can be done more efficiently. Plant breeders record the breeding history of their material but access to this information generally is limited. Dr. Ronald Hutten and colleagues at Wageningen University therefore developed a web-accessible pedigree database for cultivated potato genotypes (Potato Research 50:45-57 from which all information was taken and the figure was redrawn). Schwalbe (1956) ((Polanin x EFXII 2) x Jubel) (1932) POTATO R E S EARCH Polanin x EFXII 2 (1900) ((Polanin x EFXII 2) x Jubel) x Hindenburg (1943 Aquila (1942) Jubel (1908) Hindenburg (1916) Konsuragis (1932) Ragis 2458 Carnea Jubel (1908) Part of pedigree of cv. Schwalbe with descent of wart resistance example the variety Alma released in 1904 in Germany, in 1928 in the Netherlands, in 1978 in CzechoslovaKia and in 1984 in Austria. In each case the parents were completely different so for a correct description the year and origin needed to be supplied as well. The Netherlands heads the top ten when it comes to number of cultivars in the database with over fifteen hundred, followed by Germany and the USA with over a thousand. Japan (number ten on the list) has 128 cultivars. The oldest variety is from before 1770 without ancestors known whereas a new variety like Biogold released in 2004 has 20 generation deep ancestry in some of its branches. To set up this database use was made of lists of progenitors of all varieties released worldwide starting with the Dutch first list established in 1954, added to it lists of breeding companies, historic books and monographs of potato cultivation and breeding, potato price lists and scientific journals such as the American Potato Journal that publishes description and pedigrees of newly released varieties. Over the last 16 years the pedigree database grew from one thousand six hundred cultivars and progenitors to well over seven thousand. Separately an unpublished data base records pre-breeding material that is added to the list when a commercially released variety results. To make the lists the researchers had some difficulties to overcome such as the occurrence of synonyms such as Eersteling for Duke of York, the transcription from other languages with different script Roman such as Cyrillic, typing or writing errors. Particularly difficult was to distinguish between variety names that were used several times. The authors give as an I tried the website and found the site opening with a screen inviting visitors to enter a variety name for a “quick search of its parents or of its progeny”. Information can be shown in diagrams that represent up to five parents or children. Also a description of the variety as derived from the recommended list can be presented. A wealth of pleasantly presented information, please have a look at (http://www.plantbreeding. wur.nl/potatopedigree) ● Anton Haverkort anton.haverkort@wur.nl Ismene (1903 Potato World 2009 • number 1 37 Pagina 36

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