Pigeonpea [Cajanus cajan (L.) Millsp.] is a versatile, stress-tolerant, and nutritious grain legume, possessing\ud traits of value for enhancing the sustainability of dry sub-tropical and tropical agricultural systems.\ud The use of crop wild relatives (CWR) in pigeonpea breeding has been successful in providing important\ud resistance, quality, and breeding efficiency traits to the crop. Current breeding objectives for pigeonpea\ud include increasing its tolerance to abiotic stresses, including heat, cold, drought, and waterlogging. Here\ud we assess the potential for pigeonpea CWR to be further employed in crop improvement by compiling\ud wild species occurrence and ex situ conservation information, producing geographic distribution models\ud for the species, identifying gaps in the comprehensiveness of current germplasm collections, and using\ud ecogeographic information to identify CWR populations with the potential to contribute agronomic traits\ud of priority to breeders. The fifteen prioritized relatives of pigeonpea generally occur in South and Southeast\ud Asia to Australia, with the highest concentrations of species in southern India and northern Australia.\ud These taxa differ considerably among themselves and in comparison to the crop in their adaptations to\ud temperature, precipitation and edaphic conditions. We find that these wild genetic resources are broadly\ud under-represented in ex situ conservation systems, with 80% of species assessed as high priority for further\ud collecting, thus their availability to plant breeders is insufficient. We identify species and highlight\ud geographic locations for further collecting in order to improve the completeness of pigeonpea CWR germplasm\ud collections, with particular emphasis on potential traits for abiotic stress tolerance

Crop wild relatives have a long history of use in potato breeding, particularly for pest and disease resistance, and are expected to be increasingly used in the search for tolerance to biotic and abiotic stresses. Their current and future use in crop improvement depends on their availability in ex situ germplasm collections. As these plants are impacted in the wild by habitat destruction and climate change, actions to ensure their conservation ex situ become ever more urgent. We analyzed the state of ex situ conservation of 73 of the closest wild relatives of potato (Solanum section Petota) with the aim of establishing priorities for further collecting to fill important gaps in germplasm collections. A total of 32 species (43.8%), were assigned high priority for further collecting due to severe gaps in their ex situ collections. Such gaps are most pronounced in the geographic center of diversity of the wild relatives in Peru. A total of 20 and 18 species were assessed as medium and low priority for further collecting, respectively, with only three species determined to be sufficiently represented currently. Priorities for further collecting include: (i) species completely lacking representation in germplasm collections; (ii) other high priority taxa, with geographic emphasis on the center of species diversity; (iii) medium priority species. Such collecting efforts combined with further emphasis on improving ex situ conservation technologies and methods, performing genotypic and phenotypic characterization of wild relative diversity, monitoring wild populations in situ, and making conserved wild relatives and their associated data accessible to the global research community, represent key steps in ensuring the long-term availability of the wild genetic resources of this important crop.

PREMISE OF THE STUDY: Crop wild relatives (CWR) provide important traits for plant breeding, including pest, pathogen, and abiotic stress resistance. Therefore, their conservation and future availability are essential for food security. Despite this need, the world's genebanks are currently thought to conserve only a small fraction of the total diversity of CWR.METHODS: We define the eggplant genepool using the results of recent taxonomic and phylogenetic studies. We identify the gaps in germplasm accessions for eggplant (Solanum melongena L.) CWR by comparing georeferenced herbarium records and germplasm accessions using a gap analysis methodology implementing species distribution models (SDM). Preliminary conservation assessments using IUCN criteria were done for all species and were combined with the gap analysis to pinpoint where under‐collected and threatened CWR species coincide with high human disturbance and occur outside of protected areas.KEY RESULTS: We show that many eggplant CWR are poorly represented in genebanks compared to their native ranges. Priority areas for future collecting are concentrated in Africa, especially along the Kenya‐Tanzania border. Fourteen species of eggplant CWR are assessed as threatened or near‐threatened; these are also concentrated in eastern Africa.CONCLUSIONS: The knowledge base upon which conservation of wild relative germplasm depends must take into account both taxonomic and phylogenetic advances. Beyond traditional research focus on close relatives of crops, we emphasize the benefits of defining a broad CWR genepool, and the importance of assessing threats to wild species when targeting localities for future collection of CWR to improve crop breeding in the face of environmental change.

Crop wild relatives (CWR) are a rich source of genetic diversity for crop improvement. Combining ecogeographic and phylogenetic techniques can inform both conservation and breeding. Geographic occurrence, bioclimatic, and biophysical data were used to predict species distributions, range overlap and niche occupancy in 36 taxa closely related to sunflower (Helianthus annuus L.). Taxa lacking comprehensive ex situ conservation were identified. The predicted distributions for 36 Helianthus taxa identified substantial range overlap and asymmetry and niche conservatism. Specific taxa (e.g., Helianthus deblis Nutt., Helianthus anomalus Blake, and Helianthus divaricatus L.) were identified as targets for traits of interest, particularly for abiotic stress tolerance and adaptation to extreme soil properties. The combination of techniques demonstrates the potential for publicly available ecogeographic and phylogenetic data to facilitate the identification of possible sources of abiotic stress traits for plant breeding programs. Much of the primary genepool (wild H. annuus) occurs in extreme environments indicating that introgression of targeted traits may be relatively straightforward. Sister taxa in Helianthus have greater range overlap than more distantly related taxa within the genus. This adds to a growing body of literature suggesting that in plants (unlike some animal groups), geographic isolation may not be necessary for speciation.