title: Distributions, ex situ conservation priorities, and genetic resource potential of crop wild relatives of sweetpotato [Ipomoea batatas (L.) Lam., I. series Batatas].
abstract: Crop wild relatives of sweetpotato [Ipomoea batatas (L.) Lam., I. series Batatas] have the potential to contribute to breeding objectives for this important root crop. Uncertainty in regard to species boundaries and their phylogenetic relationships, the limited availability of germplasm with which to perform crosses, and the difficulty of introgression of genes from wild species has constrained their utilization. Here, we compile geographic occurrence data on relevant sweetpotato wild relatives and produce potential distribution models for the species. We then assess the comprehensiveness of ex situ germplasm collections, contextualize these results with research and breeding priorities, and use ecogeographic information to identify species with the potential to contribute desirable agronomic traits. The fourteen species that are considered the closest wild relatives of sweetpotato generally occur from the central United States to Argentina, with richness concentrated in Mesoamerica and in the extreme Southeastern United States. Currently designated species differ among themselves and in comparison to the crop in their adaptations to temperature, precipitation, and edaphic characteristics and most species also show considerable intraspecific variation. With 79% of species identified as high priority for further collecting, we find that these crop genetic resources are highly under-represented in ex situ conservation systems and thus their availability to breeders and researchers is inadequate. We prioritize taxa and specific geographic locations for further collecting in order to improve the completeness of germplasm collections. In concert with enhanced conservation of sweetpotato wild relatives, further taxonomic research, characterization and evaluation of germplasm, and improving the techniques to overcome barriers to introgression with wild species are needed in order to mobilize these genetic resources for crop breeding.
authors.affiliation: International Center for Tropical Agriculture, Cali Colombia ; Centre for Crop Systems Analysis, Wageningen University, Wageningen Netherlands.
authors.forename: Colin K
authors.initials: CK
authors.lastname: Khoury
authors.affiliation: International Potato Center, CGIAR Research Program on Roots, Tubers and Bananas, Lima Peru.
authors.forename: Bettina
authors.initials: B
authors.lastname: Heider
authors.affiliation: International Center for Tropical Agriculture, Cali Colombia ; School of Biosciences, University of Birmingham, Birmingham UK.
authors.forename: Nora P
authors.initials: NP
authors.lastname: Castañeda-Álvarez
authors.affiliation: International Center for Tropical Agriculture, Cali Colombia.
authors.forename: Harold A
authors.initials: HA
authors.lastname: Achicanoy
authors.affiliation: International Center for Tropical Agriculture, Cali Colombia.
authors.forename: Chrystian C
authors.initials: CC
authors.lastname: Sosa
authors.affiliation: Department of Biological Sciences, Southeastern Louisiana University, Hammond, LA USA.
authors.forename: Richard E
authors.initials: RE
authors.lastname: Miller
authors.affiliation: Department of Plant Sciences, University of Oxford, Oxford UK.
authors.forename: Robert W
authors.initials: RW
authors.lastname: Scotland
authors.affiliation: Department of Plant Sciences, University of Oxford, Oxford UK.
authors.forename: John R I
authors.initials: JR
authors.lastname: Wood
authors.affiliation: International Potato Center, CGIAR Research Program on Roots, Tubers and Bananas, Lima Peru.
authors.forename: Genoveva
authors.initials: G
authors.lastname: Rossel
authors.affiliation: Department of Plant Biology, University of Georgia, Athens, GA USA.
authors.forename: Lauren A
authors.initials: LA
authors.lastname: Eserman
authors.affiliation: Plant Genetic Resources Conservation Unit, United States Department of Agriculture - Agricultural Research Service, Griffin, GA USA.
authors.forename: Robert L
authors.initials: RL
authors.lastname: Jarret
authors.affiliation: Department of Horticultural Science, North Carolina State University, Raleigh, NC USA.
authors.forename: G C
authors.initials: GC
authors.lastname: Yencho
authors.affiliation: International Center for Tropical Agriculture, Cali Colombia ; Department of Horticulture and Crop Science, The Ohio State University, Columbus, OH USA.
authors.forename: Vivian
authors.initials: V
authors.lastname: Bernau
authors.affiliation: International Potato Center, CGIAR Research Program on Roots, Tubers and Bananas, Lima Peru.
authors.forename: Henry
authors.initials: H
authors.lastname: Juarez
authors.affiliation: International Center for Tropical Agriculture, Cali Colombia.
authors.forename: Steven
authors.initials: S
authors.lastname: Sotelo
authors.affiliation: International Center for Tropical Agriculture, Cali Colombia ; International Potato Center, CGIAR Research Program on Roots, Tubers and Bananas, Lima Peru.
authors.forename: Stef
authors.initials: S
authors.lastname: de Haan
authors.affiliation: Centre for Crop Systems Analysis, Wageningen University, Wageningen Netherlands.
authors.forename: Paul C
authors.initials: PC
authors.lastname: Struik
keywords: crop diversity; crop improvement; crop wild relatives; food security; gap analysis; plant genetic resources