Submitted to: International Botanical Congress
Publication Type: Abstract Only
Publication Acceptance Date: 8/26/2005
Publication Date: 8/26/2005
Citation: Spooner, D.M., Gavrilenko, T., Stephenson, S.A., Bamberg, J.B., Salas, A., Hijmans, R.J. 2005. Ecogeographic distribution of polyploidy levels in wild and cultivated potatoes (Solanum Section Petota). XVII International Botanical Congress Abstracts. p. 1499. Interpretive Summary:
Technical Abstract: Wild potatoes (Solanum sect. Petota) occur from the southwestern USA to Chile and Uruguay. There are diploids, triploids, tetraploids, pentaploids and hexaploids. We compiled 8700 reports of ploidy determination, including 912 first published here, covering 186 of the 188 of sect. Petota (including cultigen S. tuberosum). We analyzed the incidence and eco-geographic distribution of ploidy levels to test hypotheses of adaptation to new environments and of range expansion by polyploids. Thirty-six percent of the wild species are entirely or partly polyploid. Multiple cytotypes exist in 22 species, mostly as diploid and triploid. Diploids occupy a larger area than polyploids, but tetraploid species have similar average range sizes as diploid species. Polyploid species frequency is much higher from Mexico to Ecuador than further south. Compared to diploids, triploids tend to occur in warmer and drier areas, while higher level polyploids tend to occur in relatively cold areas. Diploids are absent from Costa Rica to southern Colombia, the wettest part of the group’s range. These results suggest that polyploidy played an important role in range expansions of the group. Tetraploid cytotypes of cultivated S. tuberosum occur more frequently than the diploids; the triploids and pentaploids are restricted to colder and drier areas.