Societal Impact Statement Crop wild relatives (CWR) are plant taxa closely related to crops and are a source of high genetic diversity that can help adapt crops to the impacts of global change, particularly to meet increasing consumer demand in the face of the climate crisis. CWR provide vital ecosystem services and are increasingly important for food and nutrition security and sustainable and resilient agriculture. They therefore are of major biological, social, cultural and economic importance. Assessing the extinction risk of CWR is essential to prioritise in situ and ex situ conservation strategies in Mesoamerica to guarantee the long‐term survival and availability of these resources for present and future generations worldwide. Summary Ensuring food security is one of the world's most critical issues as agricultural systems are already being impacted by global change. Crop wild relatives (CWR)—wild plants related to crops—possess genetic variability that can help adapt agriculture to a changing environment and sustainably increase crop yields to meet the food security challenge. Here we report the results of an extinction risk assessment of 224 wild relatives of some of the world's most important crops (i.e. chilli pepper, maize, common bean, avocado, cotton, potato, squash, vanilla and husk tomato) in Mesoamerica—an area of global significance as a centre of crop origin, domestication and of high CWR diversity. We show that 35% of the selected CWR taxa are threatened with extinction according to The International Union for Conservation of Nature (IUCN) Red List demonstrates that these valuable genetic resources are under high anthropogenic threat. The dominant threat processes are land use change for agriculture and farming, invasive and other problematic species (e.g. pests, genetically modified organisms) and use of biological resources, including overcollection and logging. The most significant drivers of extinction relate to smallholder agriculture—given its high incidence and ongoing shifts from traditional agriculture to modern practices (e.g. use of herbicides)—smallholder ranching and housing and urban development and introduced genetic material. There is an urgent need to increase knowledge and research around different aspects of CWR. Policies that support in situ and ex situ conservation of CWR and promote sustainable agriculture are pivotal to secure these resources for the benefit of current and future generations.

Crop wild relatives (CWR) are valuable resources for crop breeding due to their close genetic relationship to the cultivated plants and their wide genetic variation, allowing the introgression of desirable traits into the crops, such as resistance to plant pests and diseases or adaptability to climate change. Mexico is a centre of agrobiodiversity, including CWR, but climate change, and other factors, are contributing to the loss of important Mexican CWR genetic diversity. The in situ and ex situ conservation status of Mexican priority CWR were assessed through a gap analysis as part of a national CWR conservation strategy for Mexico, to ensure the long-term preservation and improve the availability of these genetic resources. A set of 310 priority CWR taxa, previously identified as part of the national CWR inventory for Mexico, were analysed. Species distribution modelling and ecogeographic diversity analyses were used to detect gaps in in situ and ex situ conservation at taxon and ecogeographic levels. Priority target sites were identified throughout the country for complementary in situ and ex situ conservation of these taxa. The results obtained allow us to make recommendations for immediate conservation actions, thus helping to mitigate the threats to Mexican agrobiodiversity and enhance both national and global food security.

Crop wild relatives (CWR) are valuable sources of variation for the genetic improvement of crops. Mexico is an important center of diversity of crops and CWR. However, this diversity is threatened by climate change, habitat degradation, increasing human population, among other factors. Given the large number of CWR, the creation of a CWR inventory is the starting point for the development of a national CWR conservation strategy. The process for the preparation of a national CWR inventory for Mexico consisted of (i) producing a list of national crop species, (ii) matching the crop genera with the list of national flora to produce a CWR checklist, and (iii) prioritizing the CWR checklist according to a series of selection criteria and using a ranking system. The selection criteria included the economic value of the related crop, the potential for crop improvement, food intake, threat status, geographical distribution, and crop use. Applying these criteria, 310 prioritized CWR taxa were selected (~2% of the national CWR diversity), integrating the national CWR inventory. They are mostly related to food crops of national but also global importance, such as maize (Zea mays L.), common bean (Phaseolus vulgaris L.), chili pepper (Capsicum annuum L.), squash (Cucurbita spp.), potato (Solanum tuberosum L.), cassava (Manihot esculenta Crantz), and sweet potato [Ipomoea batatas (L.) Lam.]. Approximately 31% of the taxa are endemic to Mexico. The inventory will help to develop in situ and ex situ conservation plans as part of a national CWR conservation strategy.

El estado de Tamaulipas en México es considerado como parte de los centros de origen del maíz nativo, los maíces que ahí se cultivan poseen características agronómicas de importancia y son ampliamente diversos; sin embargo, los estudios de diversidad en el estado han sido pocos. Se analizó la diversidad morfológica y agronómica entre poblaciones de maíz nativo cultivadas en el Altiplano de Tamaulipas. Se establecieron experimentos en los municipios de Jaumave, Tula y Güémez, Tamaulipas, bajo un diseño experimental de bloques completos al azar en los ciclos de siembra otoño-invierno 2016-2017 y primavera-verano del 2017, con 98 poblaciones de maíz nativo y dos testigos. Se registraron 33 caracteres morfológicos, se sometieron a análisis de varianza combinado; la agrupación de la diversidad se realizó mediante análisis de componentes principales. El análisis de componentes principales explico el 73.96 % de la variación total y mostró que los caracteres fenológicos y de mazorca fueron los que mayormente sustentaron la variación morfológica. El análisis de conglomerados permitió la identificación de dos grandes grupos morfológicos, donde predominó la raza Ratón. La variación del maíz nativo de Tamaulipas es amplia y contínua, en la cual se podrían encontrar alelos de interés para incorporarlos a programas de mejoramiento genético de maíz.

Conservation programmes are always limited by available resources. Careful planning is therefore required to increase the efficiency of conservation and gap analysis can be used for this purpose. This method was used to assess the representativeness of current ex situ and in situ conservation actions of 234 priority crop wild relatives (CWR) in Indonesia. This analysis also included species distribution modelling, the creation of an ecogeographical land characterization map, and a complementarity analysis to identify priorities area for in situ conservation and for further collecting of ex situ conservation programmes. The results show that both current ex situ and in situ conservation actions are insufficient. Sixty-six percent of priority CWRs have no recorded ex situ collections. Eighty CWRs with ex situ collections are still under-represented in the national genebanks and 65 CWRs have no presence records within the existing protected area network although 60 are predicted to exist in several protected areas according to their potential distribution models. The complementarity analysis shows that a minimum of 61 complementary grid areas (complementary based on grid cells) are required to conserve all priority taxa and 40 complementary protected areas (complementary based on existing protected areas) are required to conserve those with known populations within the existing in situ protected area network. The top ten of complementary protected areas are proposed as the initial areas for the development of CWR genetic reserves network in Indonesia. It is recommended to enhanced coordination between ex situ and in situ conservation stakeholders for sustaining the long term conservation of CWR in Indonesia. Implementation of the research recommendations will provide for the first time an effective conservation planning of Indonesia’s CWR diversity and will significantly enhance the country’s food and nutritional security.