Originating from the Andean region and co-evolved with its food plant, the potato (Solanum sp.), the potato tuber moth Phthorimaea operculella (Zeller) has become an invasive potato pest globally. The hypothesis of our present study was that the future distribution and abundance (damage potential) of this pest will be greatly affected by climate-change-caused changes in temperature. We used a process-based climatic phenology model for P. operculella and applied three risk indices (establishment-, generation, and activity index) in a geographic information system (GIS) environment to map and quantify changes for climate change scenarios of the year 2050 based on downscaled climate-change data of the scenario A1B from the WorldClim database. All applications and simulations were made using the Insect Life Cycle Modeling (ILCYM) software recently developed by The International Potato Center, Lima, Peru. The study concludes that there are three possible main scenarios of changes that may simultaneously occur: (1) the P. operculella damage potential will progressively increase in all regions where the pest already prevails today with an excessive increase in warmer cropping regions of the tropics and subtropics. In regions where P. operculella is established and develops >4 generations per year, economic losses are likely to occur; under the current climate, >4 generations are developed on 30.1% of the total potato production area worldwide, which will increase until the year 2050 to 42.4%, equal to an increase of 2,409,974 ha of potato under new infestation. (2) A range expansion in temperate regions of the northern hemisphere with additionally 8.6% (699,680 ha), 4.2% (32,873 ha), and 2.7% (234,404 ha) of the potato production area under higher risk in Asia, North America, and Europe, with moderate increases of its damage potential. (3) A range expansion in tropical temperate mountainous regions with a moderate increase of its damage potential; e.g., in Bolivia, Ecuador and Peru 44,281 ha, 9569 ha, and 39,646 ha of potato will be under new risk of infestation. The ILCYM software allowed a detailed analysis of possible climate-change-induced changes in temperature on P. operculella distribution and damage potential. Further, this tool offers means of overcoming limitations in predictions and mapping experienced with climate data interpolation and resolution by spatial point-by-point simulations at locations of interest. The methodology is proposed as a very helpful tool for adaptation planning in integrated pest management.
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.