Perennial Life History Research Articles

Edaphic specialization onto bare, rocky outcrops as a factor in the evolution of desert angiosperms

Understanding the processes that enable organisms to shift into more arid environments as they emerge is critical for gauging resilience to climate change, yet these forces remain poorly known. In a comprehensive clade-based study, we investigate recent shifts into North American deserts in the rock daisies (tribe Perityleae), a diverse tribe of desert sunflowers (Compositae). We sample rock daisies across two separate contact zones between tropical deciduous forest and desert biomes in western North America and infer a time-calibrated phylogeny based on target capture sequence data. We infer biome shifts using Bayesian inference with paleobiome-informed models and find evidence for seven independent shifts into desert habitats since the onset of aridification in the late Miocene. The earliest shift occurred out of tropical deciduous forests and led to an extensive radiation throughout North American deserts that accounts for the majority of extant desert rock daisies. Estimates of life history and micro-habitat in the rock daisies reveal a correlation between a suffrutescent perennial life history and edaphic endemism onto rocky outcrops, an ecological specialization that evolved prior to establishment and diversification in deserts. That the insular radiation of desert rock daisies stemmed from ancestors preadapted for dry conditions as edaphic endemics in otherwise densely vegetated tropical deciduous forests in northwest Mexico underscores the crucial role of exaptation and dispersal for shifts into arid environments.

Autopolyploid establishment depends on life-history strategy and the mating outcomes of clonal architecture.

Polyploidy is a significant component in the evolution of many taxa, particularly plant groups. However, new polyploids face substantial fitness disadvantages due to a lack of same-cytotype mates, and the factors promoting or preventing polyploid establishment in natural populations are often unclear. We develop spatially explicit agent-based simulation models to test the hypothesis that a perennial life history and clonal propagation facilitate the early stages of polyploid establishment and persistence. Our models show that polyploids are more likely to establish when they have longer life spans than diploids, especially when self-fertilization rates are high. Polyploids that combine sexual and clonal reproduction can establish across a wide range of life histories, but their success is moderated by clonal strategy. By tracking individuals and mating events, we reveal that clonal architecture has a substantial impact on the spatial structure of the mixed diploid-polyploid population during polyploid establishment: altering patterns of mating within or between cytotypes via geitonogamous self-fertilization, the mechanisms through which polyploid establishment proceeds, and the final composition of the polyploid population. Overall, our findings provide novel insight into the role of clonal structure in modulating the complex relationship between polyploidy, perenniality, and clonality and offer testable predictions for future empirical work.

Research Progress on Genetic Basis of Fruit Quality Traits in Apple (Malus × domestica).

Identifying the genetic variation characteristics of phenotypic traits is important for fruit tree breeding. During the long-term evolution of fruit trees, gene recombination and natural mutation have resulted in a high degree of heterozygosity. Apple (Malus × domestica Borkh.) shows strong ecological adaptability and is widely cultivated, and is among the most economically important fruit crops worldwide. However, the high level of heterozygosity and large genome of apple, in combination with its perennial life history and long juvenile phase, complicate investigation of the genetic basis of fruit quality traits. With continuing augmentation in the apple genomic resources available, in recent years important progress has been achieved in research on the genetic variation of fruit quality traits. This review focuses on summarizing recent genetic studies on apple fruit quality traits, including appearance, flavor, nutritional, ripening, and storage qualities. In addition, we discuss the mapping of quantitative trait loci, screening of molecular markers, and mining of major genes associated with fruit quality traits. The overall aim of this review is to provide valuable insights into the mechanisms of genetic variation and molecular breeding of important fruit quality traits in apple.

Seasonal Phenology and Colony Longevity Patterns in a Predatory Social Wasp

Social wasps play critical ecological roles in an ecosystem, providing a diversity of services and some disservices. Yellowjacket wasps (Vespula spp.) in particular are well known for shaping arthropod communities via predation and competition for resources. In part due to their sociality and large colony sizes, Vespula can have a profound ecological impact on local communities. Such effects can be magnified when colonies exhibit a perennial life history, in which a colony will overwinter, persist for more than one year, and become orders of magnitude larger in size compared to typical annual colonies. Despite growing interest in the factors that influence colony success, we currently lack the ability to predict when yellowjackets may have a high-abundance or outbreak year. This highlights the need for a critical understanding of the phenological patterns of foraging activity, colony distribution, and senescence. Here, we quantify the seasonal activity and foraging rates of 123 colonies of the western yellowjacket, V. pensylvanica, in its native range over 4 consecutive years. Average colony longevity was about 1 month longer than previously reported for this species, and colonies with later peaks in activity and higher average traffic rates persisted longer into the winter. Longer-lived colonies tended to cluster together within a year, but not between years. We found 3 perennial colonies (2.4% of all colonies), and they exhibited tenfold higher peak traffic rates compared to annual colonies. By identifying temporal and spatial patterns in survivorship and colony longevity, we gain insight into the factors associated with prolonged survival time and increased likelihood of overwintering in yellowjacket wasps.

Tradeoffs in life history investment of eelgrass Zostera marina across estuarine intertidal conditions

Plant ecological strategies are associated with tradeoffs between investment in each module (e.g. leaf, stem) and the longevity or rate of production of these modules, while clonal species can exhibit additional tradeoffs between asexual and sexual reproduction. To evaluate intraspecific life history patterns, we applied multivariate analyses to a suite of 7 distinct traits plus density in a clonal marine angiosperm (eelgrassZostera marina) across sites and seasons. We expected life history tradeoffs for ecotypes at different sites, but positively correlated investment seasonally due to variation in photoperiod at 46°N. Relative growth rate (RGR), an indicator of suitable growing conditions, varied seasonally by 3-fold and strongly tracked photoperiod, with small variation among sites. Consistent with tradeoffs across ecotypes, shoot size (length, mass), module production (leaf and shoot emergence rates), and flowering tended to load in opposite ways on the first 2 principal components (62% of total trait variation). Annual life histories were separated from perennial life histories in both space (higher tidal elevations) and time (2 mo lag in flowering). In perennial populations, flowering peaked seasonally with daylength, but size continued to increase after the summer solstice, and asexual branching occurred in early spring and late summer, so investment in most life history traits did not align with RGR. Seasonal variation in shoot density was pronounced for small ecotypes, but for larger ecotypes, variation occurred through change in shoot size. Because the functional traits of foundation species help shape their role, documented covariation in these traits addresses a gap between environmental conditions and community response that is mediated by biogenic structure.

The role of genus and life span in predicting seed and vegetative trait variation and correlation in Lathyrus, Phaseolus, and Vicia.

PremiseAnnual and perennial life history transitions are abundant among angiosperms, and understanding the phenotypic variation underlying life span shifts is a key endeavor of plant evolutionary biology. Comparative analyses of trait variation and correlation networks among annual and perennial plants is increasingly important as new herbaceous perennial crops are being developed for edible seed. However, it remains unclear how seed to vegetative growth trait relationships correlate with life span.MethodsTo assess the relative roles of genus and life span in predicting phenotypic variation and trait correlations, we measured seed size and shape, germination proportion, and early‐life‐stage plant height and leaf growth over 3 mo in 29 annual and perennial, herbaceous congeneric species from three legume genera (Lathyrus, Phaseolus, and Vicia).ResultsGenus was the strongest predictor of seed size and shape variation, and life span consistently predicted plant height and leaf number at single time points. Correlation networks revealed that annual species had significant associations between seed traits and vegetative traits, whereas perennials had no significant seed‐vegetative associations. Each genus also differed in the extent of integration between seed and vegetative traits, as well as within‐vegetative‐trait correlation patterns.ConclusionsGenus and life span were important for predicting aspects of early‐life‐stage phenotypic variation and trait relationships. Differences in phenotypic correlation may indicate that selection on seed size traits will impact vegetative growth differently depending on life span, which has important implications for nascent perennial breeding programs.

Arabis alpina: A perennial model plant for ecological genomics and life-history evolution.

Many model organisms were chosen and achieved prominence because of an advantageous combination of their life‐history characteristics, genetic properties and also practical considerations. Discoveries made in Arabidopsis thaliana, the most renowned noncrop plant model species, have markedly stimulated studies in other species with different biology. Within the family Brassicaceae, the arctic–alpine Arabis alpina has become a model complementary to Arabidopsis thaliana to study the evolution of life‐history traits, such as perenniality, and ecological genomics in harsh environments. In this review, we provide an overview of the properties that facilitated the rapid emergence of A. alpina as a plant model. We summarize the evolutionary history of A. alpina, including genomic aspects, the diversification of its mating system and demographic properties, and we discuss recent progress in the molecular dissection of developmental traits that are related to its perennial life history and environmental adaptation. From this published knowledge, we derive open questions that might inspire future research in A. alpina, other Brassicaceae species or more distantly related plant families.

Is plant reproductive efficiency expressed on a continuum of facilitation and competition?

AbstractQuestionsCompetition and facilitation form a continuum of interactions between plants from intensely negative to intensely positive. Competition has long been understood to be a major selective force driving the expression of adaptive strategies in plants. However, we remain uncertain if facilitation plays a similar role. In previous studies, the relative allocation to reproduction across plant species increases with increasing competition intensity, and this observation is generally consistent with life history theory (rather than traditional plant strategy theory). However, is facilitation also an important force in shaping adaptive strategies in plants?MethodsWe surveyed the literature for plant facilitation studies that included measures of plant performance (e.g. vegetative biomass, height) and reproduction (e.g. reproductive biomass, seed number). We tested for a relationship between relative reproductive efficiency (the allocation to reproduction in the presence of neighbours relative to the allocation of reproduction in the absence of neighbours), and facilitation interaction intensity (i.e. the increase in plant performance due to the presence of neighbours). We also compared this relationship to the previously published relationship between reproductive efficiency and competition intensity to test for a continuum of strategies on an axis of plant–plant interactions from intensely positive (facilitation) to intensely negative (competition).ResultsThe overall relationship between facilitation intensity and the relative reproductive efficiency is a common negative relationship for both annual and perennial life histories. We found a highly significant negative relationship across the competition–facilitation continuum, with reproductive efficiency in the presence of neighbouring vegetation high under intense competition and low under intense facilitation.ConclusionPlant reproductive strategies are expressed on a continuum of interactions from facilitation to competition. This continuum of interactions will be important in understanding how interactions between plants drive the evolution of adaptive strategies and control coexistence and diversity in plant communities.

The Evolution of Annual and Perennial Plant Life Histories: Ecological Correlates and Genetic Mechanisms

Flowering plants exhibit two principal life-history strategies: annuality (living and reproducing in one year) and perenniality (living more than one year). The advantages of either strategy depend on the relative benefits of immediate reproduction balanced against survivorship and future reproduction. This trade-off means that life-history strategies are associated with particular environments, with annuals being found more often in unpredictable habitats. Annuality and perenniality are the outcome of developmental genetic programs responding to their environment, with perennials being distinguished by their delayed competence to flower and reversion to growth after flowering. Evolutionary transitions between these strategies are frequent and have consequences for mating systems and genome evolution, with perennials being more likely to outcross with higher inbreeding depression and lower rates of molecular evolution. Integrating expectations from life-history theory with knowledge of the developmental genetics of flowering and seasonality is required to understand the mechanisms involved in the evolution of annual and perennial life histories.

Switching from monocarpic to polycarpic perennial life histories in a cold climate: a commentary on ‘Physiological costs of clonal growth’

Switching from monocarpic to polycarpic perennial life histories in a cold climate: a commentary on ‘Physiological costs of clonal growth’

Evolutionary associations between polyploidy, clonal reproduction, and perenniality in the angiosperms

Clonal reproduction is thought to facilitate polyploid establishment in the angiosperms, but the evolutionary relationship between polyploidy and clonality has not been thoroughly tested. A perennial life history may confer many of the same advantages, and the relative importance of clonality versus perenniality is unknown. We used phylogenetic comparative analyses of 1751 species to examine associations between polyploidy, clonality, and life history. We test hypotheses of co-evolution by determining the sequence of trait development. Polyploidy is associated with both clonality and perenniality across species, and analyses show that clonality can be an important predictor of polyploidy beyond perenniality. Tests of directionality on our full dataset suggest that polyploidy is more likely to promote clonality or perenniality than vice versa, although there are significant differences in patterns of co-evolution among major angiosperm groups. Our results suggest that polyploidy and clonal reproduction are evolutionarily associated across the angiosperms, even when perenniality is considered, but we find little evidence at the whole-angiosperm level for the hypothesis that clonality promotes polyploidy. However, variation among different clades indicates that polyploidy and clonality are interacting in diverse ways, likely to be due to the variable roles of clonality in their evolutionary histories.

Drought regimens predict life history strategies in Heliophila.

Explaining variation in life history strategies is an enduring goal of evolutionary biology and ecology. Early theory predicted that for plants, annual and perennial life histories reflect adaptations to environments that experience alternative drought regimens. Nevertheless, empirical support for this hypothesis from comparative analyses remains lacking. Here, we test classic life history theory in Heliophila L. (Brassicaceae), a diverse genus of flowering plants native to Africa, controlling for phylogeny and integrating 34yr of satellite-based drought detection with 2192 herbaria occurrence records. We find that the common ancestor of these species was likely to be an annual, and that perenniality and annuality have repeatedly evolved, an estimated seven and five times, respectively. By comparing historical drought regimens, we show that annuals rather than perennial species occur in environments where droughts are significantly more frequent. We also find evidence that annual plants adapt to predictable drought regimens by escaping drought-prone seasons as seeds. These results yield compelling support for longstanding theoretical predictions by revealing the importance of drought frequency and predictability to explain plant life history. More broadly, this work highlights scalable approaches, integrating herbaria records and remote sensing to address outstanding questions in evolutionary ecology.

Molecular phylogenetics and species delimitation in annual species of Hydrocotyle (Araliaceae) from South Western Australia

Hydrocotyle L. is a cosmopolitan genus, with approximately 130 species, of mostly perennial herbs in the family Araliaceae. The genus includes around 95 perennial and 35 annual species, with all annual species endemic to Australia. In this study, I used sequences of a nDNA marker (ETS) and two cpDNA markers (psbA–trnH and trnL–trnF) to reconstruct phylogenetic relationships among the annual species of Hydrocotyle. The final sampling included 21 species of Hydrocotyle and seven outgroup taxa. The phylogenetic analyses of the combined molecular dataset (i.e., ETS, psbA–trnH and trnL–trnF) recovered three major clades within Hydrocotyle, defined by annual or perennial life histories, and the presence/absence of floral bracts. The topology reconstructed here indicates that there is insufficient molecular evidence for the formal recognition of two putative new species, Hydrocotyle sp. Hamelinensis and Hydrocotyle sp. Puberula, previously identified on the basis of morphology. More specifically, H. sp. Hamelinensis is conspecific with H. tetragonocarpa Bunge, while H. sp. Puberula is conspecific with H. scutellifera Benth. Morphological studies of H. tetragonocarpa revealed that this species is andromonoecious and has heterocarpic schizocarps. Fertile plants of H. tetragonocarpa bear fruit that are either ovoid and wingless or broadly obcordate and winged. A detailed re-examination of the schizocarp surfaces of H. scutellifera indicated that these schizocarps are either glabrous or papillate, with neither of these two character states co-varying with any other vegetative or reproductive traits. The phylogeny of the annual Hydrocotyle recovered a paraphyletic Hydrocotyle, with Neosciadium glochidiatum (Benth.) Domin nested within the genus. This study is the first to reconstruct a molecular phylogeny of Hydrocotyle using samples of both annual and perennial taxa. The findings from this study provide a phylogenetic framework for future systematic and taxonomic research within the genus.

Evolutionary history of the arid climate‐adapted Helichrysum (Asteraceae: Gnaphalieae): Cape origin and association between annual life‐history and low chromosome numbers

AbstractThe basal grade of the large, widely‐distributed Helichrysum‐Anaphalis‐Pseudognaphalium (HAP) clade (Asteraceae, Gnaphalieae) comprises exclusively southern African taxa. These species possess unusual trait combinations relative to the remaining species (a high proportion of annuals, unusual capitulum arrangement, and low base chromosome numbers). A time‐proportional Bayesian phylogenetic hypothesis is generated from nuclear ribosomal sequences from 110 accessions. Ancestral area, life history, and base chromosome number are reconstructed using maximum likelihood, and correlations between life‐history and chromosome number are tested in a phylogenetic framework. The results show that the HAP clade probably originated and experienced initial diversification in the Greater Cape Floristic Region in the Early to Middle Miocene. The ancestor of the HAP clade is inferred to have been perennial with x = 7 base chromosome number. Several independent acquisitions of the annual life‐history are inferred, accompanied by reductions to x = 4 and 5. A single reversal to perennial life history is associated with a subsequent change back to the state of x = 7. Origin and early diversification within the HAP clade follows the pattern of multi‐area seeded radiations within southern Africa, with subsequent migrations to the rest of Africa and the Northern Hemisphere. Occupation of drier habitats with shorter growing seasons may select for the acquisition of a shorter life‐cycle, and our results indicate a strong association between short life‐cycle and reduced chromosome number.

Conserved thermal performance curves across the geographic range of a gametophytic fern.

Species-level responses to environmental change depend on the collective responses of their constituent populations and the degree to which populations are specialized to local conditions. Manipulative experiments in common-garden settings make it possible to test for population variation in species’ responses to specific climate variables, including those projected to shift as the climate changes in the future. While this approach is being applied to a variety of plant taxa to evaluate their responses to climate change, these studies are heavily biased towards seed-bearing plant species. Given several unique morphological and physiological traits, fern species may exhibit very different responses from angiosperms and gymnosperms. Here, we tested the hypothesis that previously detected population differentiation in a fern species is due to differentiation in thermal performance curves among populations. We collected explants from six populations spanning the species’ geographic range and exposed them to 10 temperature treatments. Explant survival, lifespan and the change in photosynthetic area were analysed as a function of temperature, source population and their interaction. Overall results indicated that explants performed better at the lowest temperature examined, and the threshold for explant performance reflects maximum temperatures likely to be experienced in the field. Surprisingly, explant fitness did not differ among source populations, suggesting that temperature is not the driver behind previously detected patterns of population differentiation. These results highlight the importance of other environmental axes in driving population differentiation across a species range, and suggest that the perennial life history strategy, asexual mating system and limited dispersal potential of Vittaria appalachiana may restrict the rise and differentiation of adaptive genetic variation in thermal performance traits among populations.

Life-history trade-offs promote the evolution of dioecy.

Most dioecious plants are perennial and subject to trade-offs between sexual reproduction and vegetative performance. However, these broader life-history trade-offs have not usually been incorporated into theoretical analyses of the evolution of separate sexes. One such analysis has indicated that hermaphroditism is favoured over unisexuality when female and male sex functions involve the allocation of nonoverlapping types of resources to each sex function (e.g. allocations of carbon to female function vs. allocations of nitrogen to male function). However, some dioecious plants appear to conform to this pattern of resource allocation, with different resource types allocated to female vs. male sex functions. Using an evolutionarily stable strategy approach, we show that life-history trade-offs between sexual reproduction and vegetative performance enable the evolution of unisexual phenotypes even when there are no direct resource-based trade-offs between female and male sex functions. This result might help explain the preponderance of perennial life histories among dioecious plants and why many dioecious plants with annual life histories have indeterminate growth with ongoing trade-offs between sexual reproduction and vegetative growth.

Molecular phylogeny of Panicum s. str. (Poaceae, Panicoideae, Paniceae) and insights into its biogeography and evolution.

Panicum sensu stricto is a genus of grasses (Poaceae) with nearly, according to this study, 163 species distributed worldwide. This genus is included in the subtribe Panicinae together with Louisiella, the latter with 2 species. Panicum and subtribe Panicinae are characterized by including annual or perennial taxa with open and lax panicles, and spikelets with the lower glume reduced; all taxa also share a basic chromosome number of x = 9 and a Kranz leaf blade anatomy typical of the NAD-me subtype photosynthetic pathway. Nevertheless, the phylogenetic placements of many Panicum species, and the circumscription of the genus, remained untested. Therefore, phylogenetic analyses were conducted using sequence data from the ndhF plastid region, in an extensive worldwide sampling of Panicum and related genera, in order to infer evolutionary relationships and to provide a phylogenetic framework to review the classification of the genus. Diversification times, historical biogeography and evolutionary patterns of the life history (annual vs. perennial) in the subtribe and Panicum were also studied. Results obtained provide strong support for a monophyletic Panicum including 71 species and 7 sections, of which sections Arthragrostis and Yakirra are new in the genus; 7 new combinations are made here. Furthermore, 32 species traditionally assigned to Panicum were excluded from the genus, and discussed in other subtribes of Paniceae. Our study suggested that early diversification in subtribe Panicinae and Panicum occurred through the Early-Mid Miocene in the Neotropics, while the subsequent diversification of its sections mainly occurred in the Late Miocene-Pleistocene, involving multiple dispersals to all continents. Our analyses also showed that transition rates and changes between annual and perennial life history in Panicum were quite frequent, suggesting considerable lability of this trait. Changes of the life history, together with C4 photosynthesis, and the multiple dispersal events since the Mid Miocene, seem to have facilitated a widespread distribution of the genus. All these findings contribute to a better understanding of the systematics and evolution of Panicum.

18. Comparing Relationships between Plant Body Sizes and Minimum Reproductive Threshold Sizes for Species of Contrasting Life History

Two traits are fundamental in defining plant life history strategies: How big can a species get? And how big does it need to get before it can reproduce? Previous research has shown that there is a general positive relationship between these two traits, across species, and this can be accounted for as a trade-off. In this project, I explored whether this relationship differs among herbaceous species with perennial versus annual or biennial life histories. Perennials, because of their capacity to grow across several years, might generally be expected to display a relatively large MAX (maximum potential body size) and hence large MIN (minimum reproductive threshold size) compared with annuals or biennials that live only one or two years. In addition, annuals/biennials might be expected generally to have a smaller MIN for a given MAX, compared with perennials because of selection in the ancestral past — i.e. in frequently disturbed habitats, where annuals and biennials are common, predictable early death (from disturbance) has imposed strong selection to produce at least some offspring quickly, regardless of how small/suppressed the plant might be. I tested these predictions for resident plants sampled from natural populations of 105 species found in the vicinity of Kingston, Ontario. Remarkably, the results support neither prediction, and point to an alternative consequence of selection in shaping plant life history strategies; i.e. small MIN for a given MAX has also been favoured in perennials but for a different reason — as a strategy for competitive fitness.

Size and fitness responses of eelgrass (Zostera marina L.) following reciprocal transplant along an estuarine gradient

Eelgrass (Zostera marina) differs in shoot size, growth rate, and life history investment along a 30-km estuarine gradient in Willapa Bay, Washington (USA). In this study, reciprocal transplants were carried out among four sites in the estuary to test the roles of source population and outplant site for summer-season performance, a method that distinguishes any advantage of locally-tuned phenotypes and whether such trait differences are fixed or phenotypically-plastic. Shoots were measured after 2–3 months for size, leaf emergence rate (productivity) and shoot emergence rate (fitness), as well as simply finding them again (retrieval). Results generally did not support that best performance came from local shoots (few source x outplant site interactions). However, at one site, local shoots had higher fitness than other sources, and for one source, local retrieval exceeded that at other sites. Across all outplants, retrieval improved with rhizome length, suggesting that longer rhizomes provided better anchors. Fitness and productivity were both reduced for transplants into eelgrass relative to those in nearby bare areas at most sites, likely reflecting strong intraspecific competition for transplanted shoots. At this within-estuary scale in summer, morphology appeared entirely plastic, given convergence to local size, but annual vs. perennial life history was strictly a function of source population regardless of outplant site. This reciprocal transplant study supports many of the best practices for restoration, which include effective anchoring of shoots into locations with suitable environmental conditions. Matching donor populations for life history may be more important than for size, given differential phenotypic plasticity in these traits.

Tracing the domestication of the Andean root crop arracacha (Arracacia xanthorrhizaBancr.): a molecular survey confirms the selection of a wild form apt to asexual reproduction

AbstractAndean arracacha (Arracacia xanthorrhizaBancr.) is a valuable but poorly known vegetatively reproduced root crop whose origin is still unresolved. Wild tuberous forms are present in the presumed areas of domestication and have a perennial or monocarpic life history. To elucidate the origin of the cultivated form, we surveyed a molecular analysis with amplified fragment length polymorphisms (AFLPs) in a representative sample of this crop and its wild relatives from Ecuador and Peru, the presumed areas of domestication. Wild species with tuberous and non-tuberous roots were included, as well as the perennial and monocarpic forms of the presumed wild ancestor. While the two wild varieties ofA. xanthorrhizawere closest to the cultivars, they were distinguished by AFLPs. Unexpectedly, two clearly distinct groups were formed among the cultivars, one of which was significantly closer to the monocarpic wild form. However, the chloroplast DNA survey revealed greater similarity between all of the cultivars and the wild perennialA. xanthorrhiza. These results combined with the morphological and life history features, confirms the hypothesis that arracacha domestication started from the wild perennial form. We suggest this scenario of domestication followed by an unsuspected introgression in the cultivation, resulting in two cryptic genetic groups, well distinguished at the molecular level. This is an important revelation with implications in genetic resource conservation and breeding standpoints in this promissory crop.