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Title: Evidence of Allopolyploid Speciation of Wild Tetraploid Mexican Species of Solanum Series Longipedicellata Obtained by In Situ Hybridization

item Spooner, David

Submitted to: Genome
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/2/2008
Publication Date: 9/9/2008
Citation: Pendinen, G., Gavrilenko, T., Jiang, J., Spooner, D.M. 2008. Evidence of Allopolyploid Speciation of Wild Tetraploid Mexican Species of Solanum Series Longipedicellata Obtained by In Situ Hybridization. Genome. 51(9):714-720.

Interpretive Summary: Chromosomes are the structures in plant cells that contain the hereditary material called DNA. Polyploidy is a term referring to plants that have extra sets of chromosomes, and allopolyploidy refers to a plant having chromosomes obtained through the hybridization of different plant species. Some wild potato species are allopolyploid, and this study uses a technique called chromosome painting to examine the parents of allopolyploid Mexican potato species technically classified in Solanum series Longipedicellata. The results support prior ideas of the parents of these allopolyploid species being the diploid species S. verrucosum and the Mexican diploid species S. jamesii, or a species closely related to S. jamesii. The data are useful to potato breeders and potato taxonomists because they demonstrate the genetic composition of members of series Longipedicellata.

Technical Abstract: Potatoes are classified in Solanum section Petota. Of the approximately 190 potato species, about 25% are polyploid. Determination of the type of polyploidy and the development of the genome concept for species of the section Petota has been based mainly on the analysis of chromosome pairing in species and their hybrids. Wild polyploid species of the series Longipedicellata are considered as strict allopolyploids based on meiotic analyses. This study investigates the origin of the putative allotetraploids from Mexico in Solanum series Longipedicellata. The diploid species Solanum verrucosum was suggested as one parent based on geographical and morphological data. The B genome donor of the polyploids of series Longipedicellata is still unknown. Using fluorescent in situ hybridization techniques (GISH and FISH) we examine series Longipedicellata species Solanum stoloniferum and S. hjertingii. The data support allopolyploid origins of these species from S. verrucosum as one genome donor, and the closely related species S. jamesii, S. cardiophyllum, or S. ehrenbergii as the other genome donor. From the practical point of view Mexican tetraploid species possess a high level of disease and pest resistance; knowledge of their genome constitution will help breeders in introgressive programs to enrich genepool of common potato.