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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 20 cm shoots by the same tuber in subsequent seasons of a set of 162 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 half of jam populations 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. 

Abstract Premise: Plant domestication can be detected when transport, use, and manipulation of propagules impact reproductive functionality, especially in species with selfincompatible breeding systems. Methods: Evidence for human‐caused founder effect in the Four Corners potato (Solanum jamesii Torr.) was examined by conducting 526 controlled matings between archaeological and non‐archaeological populations from field‐collected tubers grown in a greenhouse. Specimens from 24 major herbaria and collection records from >160 populations were examined to determine which produced fruits. Results: Archaeological populations did not produce any fruits when self‐crossed or outcrossed between individuals from the same source. A weak ability to self‐ or outcross within populations was observed in non‐archaeological populations. Outcrossing between archaeological and non‐archaeological populations, however, produced fully formed, seed‐containing fruits, especially with a non‐archaeological pollen source. Fruit formation was observed in 51 of 162 occurrences, with minimal evidence of constraint by monsoonal drought, lack of pollinators, or spatial separation of suitable partners. Some archaeological populations (especially those along ancient trade routes) had records of fruit production (Chaco Canyon), while others (those in northern Arizona, western Colorado, and southern Utah) did not. Conclusions: The present study suggests that archaeological populations could have different origins at different times—some descending directly from large gene pools to the south and others derived from gardens already established around occupations. The latter experienced a chain of founder events, which presumably would further reduce genetic diversity and mating capability. Consequently, some archaeological populations lack the genetic ability to sexually reproduce, likely as the result of human‐caused founder effect. 

Humans have both intentional and unintentional impacts on their environment, yet identifying the enduring ecological legacies of past small-scale societies remains difficult, and as such, evidence is sparse. The present study found evidence of an ecological legacy that persists today within an semiarid ecosystem of western North America. Specifically, the richness of ethnographically important plant species is strongly associated with archaeological complexity and ecological diversity at Puebloan sites in a region known as Bears Ears on the Colorado Plateau. A multivariate model including both environmental and archaeological predictors explains 88% of the variation in ethnographic species richness (ESR), with growing degree days and archaeological site complexity having the strongest effects. At least 31 plant species important to five tribal groups (Navajo, Hopi, Zuni, Ute Mountain Ute, and Apache), including the Four Corners potato ( Solanum jamesii ), goosefoot ( Chenopodium sp.), wolfberry ( Lycium pallidum ), and sumac ( Rhus trilobata ), occurred at archaeological sites, despite being uncommon across the wider landscape. Our results reveal a clear ecological legacy of past human behavior: even when holding environmental variables constant, ESR increases significantly as a function of past investment in habitation and subsistence. Consequently, we suggest that propagules of some species were transported and cultivated, intentionally or not, establishing populations that persist to this day. Ensuring persistence will require tribal input for conserving and restoring archaeo-ecosystems containing “high-priority” plant species, especially those held sacred as lifeway medicines. This transdisciplinary approach has important implications for resource management planning, especially in areas such as Bears Ears that will experience greater visitation and associated impacts in the near future.