Mother tubers of wild potato Solanum jamesii can make shoots five times

Authors: Bamberg, John; DEL RIO, ALFONSO - University Of Wisconsin; KINDER, DAVID - Ohio Northern University; LOUDERBACK, LISBETH - University Of Utah; PAVLIK, BRUCE - University Of Utah; FERNANDEZ, CHARLES - University Of Wisconsin

Submitted to: American Journal of Potato Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/21/2023
Publication Date: 10/18/2023
Citation: Bamberg, J.B., Del Rio, A., Kinder, D., Louderback, L., Pavlik, B., Fernandez, C. 2023. Mother tubers of wild potato Solanum jamesii can make shoots five times. American Journal of Potato Research. 2023 (1-6). https://doi.org/10.1007/s12230-023-09927-1.
DOI: https://doi.org/10.1007/s12230-023-09927-1

Interpretive Summary: Potato is the world's top vegetable crop, but needs ongoing breeding for improved varieties. The US Potato Genebank, located at Sturgeon Bay, Wisconsin, preserves and distributes potato breeding stocks, including wild potato relatives, and studies their qualities. USDA/ARS scientists and collaborators discovered a new trait in a wild potato species native to the USA. Most potato tubers, when planted, expend the energy in the tuber needed to produce a stem, then shrivel and die. We tested many potato species, finding that only Solanum jamesii had substantial ability to re-sprout the same tubers and produce a shoot-- up to five times. This appears to be a remarkable new survival method. That is, if the potato in the wild establishes a shoot, but conditions kill that shoot before any new seeds or tubers are produced, that same tuber can sprout again next year. This discovery opens the door for research to study the mechanism of this trait, how it affects survival in the wild, and how it might be applied to the potato crop to make it more resilient to environmental stress.

Technical Abstract: Solanum jamesii (jam) is the only wild potato species with its natural range primarily within the USA. Its tubers are known to have unusual abilities to survive various environmental stresses. It has been observed during germplasm collecting that mother tubers (those that produced the plant) often appear to be as firm and viable as the new daughter tubers. This prompted investigation of whether such mother tubers can produce multiple seasons of shoots (after periods of intervening cool storage to simulate winter). We compared serial production of 20cm shoots by the same tuber in subsequent seasons of a set of 164 jam populations to that of a diverse set of 75 populations of 25 other potato species in greenhouse cultivation at the US Potato Genebank. It was rare for tubers of any species other than jam to produce even two serial shoots. But over 40 populations of jam were able to produce four serial shoots (M4), and 14 populations produced five serial shoots (M5) with tubers remaining firm. When we looked for associated traits, M4 and M5 populations have no apparent single geographic origin or similarity by DNA markers. But natural origin sites for M4 and M5 populations were significantly associated with ancient human habitation. This work reports a new survival mechanism in potato by which a tuber does not expend all resources in maximizing new shoot growth, but instead presumably restocks itself to survive several seasons if all other reproductive options fail. Future work could study the physiological and genetic basis of the trait, and ways it could have practical benefit to the crop.