SYSTEMATICS, GENETIC DIVERSITY ASSESSMENT, AND ACQUISITION OF POTATOES, CARROTS, AND THEIR RELATED WILD RELATIVES
Location: Vegetable Crops Research Unit
Title: The Single Andigenum Origin of Neo-Tuberosum Potato Materials is not Supported by Microsatellite and Plastid Marker Analyses
| Ghislain, M - INTL POTATO CNTR LIMA |
| Nunez, J - INTL POTATO CNTR LIMA |
| Del Rosario Herrera, M - INTL POTATO CNTR LIMA |
| Bonierbale, M - INTL POTATO CNTR LIMA |
Submitted to: Theoretical and Applied Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 5, 2008
Publication Date: January 9, 2009
Citation: Ghislain, M., Nunez, J., Del Rosario Herrera, M., Bonierbale, M., Spooner, D.M. 2009. The Single Andigenum Origin of Neo-Tuberosum Potato Materials is not Supported by Microsatellite and Plastid Marker Analyses. Theoretical and Applied Genetics. 118(5):963-969.
Interpretive Summary: Potato breeders regularly use living potato collections (germplasm) from native cultivated or wild potatoes for potato breeding. However, this germplasm often is not useful until it is selected to become more similar to modern cultivated potato. Such is the case with a collection of potato germplasm referred to as “Neo-Tuberosum” that refers to cultivated potato from the high Andes that was selected for the ability to produce tubers under the long day length conditions of Europe and other areas in the high latitudes. However, we show, through the use of DNA markers, that Neo-Tuberosum was not what it was long thought to be. Rather, it is a collection of germplasm related to native potatoes from the low altitudes and low latitudes of Chile. For 40 years, potato breeders have been making assumptions about the use of Neo-tuberosum germplasm in their breeding programs that was incorrect. We suspect that the relationship of Neo-Tuberosum to potatoes from Chile, rather than from the Andes, was the result of hybridization with Andes potatoes and rapid selection for a Chilean type. In addition, we show that the long-held assumption that breeding with Neo-Tuberosum germplasm would increase genetic diversity is incorrect. As a result, potato breeders must reconsider the historical and present value of Neo-Tuberosum germplasm for breeding programs.
Neo-Tuberosum refers to cultivated potato adapted to long-day tuberization and a syndrome of related morphological and physiological traits, developed by intercrossing and selection of short-day adapted potatoes of the Solanum tuberosum Andigenum Group, native from the Andes of western Venezuela to northern Argentina. This re-creation of the modern potato helped support the theory of an Andigenum Group origin of potato in temperate regions and the possibility to access the largely untapped diversity of the Andigenum Group germplasm by base broadening breeding. This Neo-Tuberosum derived theory has been universally accepted for almost 40 years, and has had tremendous impact in planning breeding programs and making phylogenetic conclusions in cultivated potato. We show, with simple sequence repeat (SSR) and plastid DNA marker data, that Neo-Tuberosum germplasm is closely related to Chilotanum Group landraces from lowland south-central Chile rather than to Andigenum Group germplasm. We interpret this quite unexpected result to be caused by strong rapid selection against the original Andigenum clones after unintended hybridization with Chilotanum Group germplasm. In addition, we show that Neo-Tuberosum and Andigenum Group germplasm did not serve to broaden the overall genetic diversity of advanced potato varieties, but rather that Neo-Tuberosum lines and lines not using this germplasm are statistically identical with regard to genetic diversity as assessed by SSRs. These results invalidate the long-standing Neo-Tuberosum derived theory and have implications in breeding programs and phylogenetic reconstructions of potato.