Cacti are very important in horticulture. As a consequence, wild cactus populations suffer much from illegal harvest and trade. Therefore, cacti are a priority for Botanic Gardens Conservation International, the IUCN/SSC Global Trees Specialist Group and the International Organization for Succulent Plant Study. Despite the conservation priority of cacti, genetic diversity of ex situ collections is largely undetermined and has hardly been compared with the diversity present in wild populations. In this project, a range of genomic tools will be applied to assess the amount of genetic diversity present in ex situ collections worldwide for three cactus genera and then compare this amount with the total genetic variation present in wild populations. Priority populations for ex situ conservation will be identified and the definition of a genetically representative ex situ collection (amount of genetic variation, number of accessions, etc.) will be established. Also, we will test whether endangered species with narrow distribution are genetically depauperate. The goal is to develop general guidelines and a protocol for the genetic management of ex situ collections which can support conservation strategies of cacti. Together with the larger PLAN(E)T project we aim to generalise the developed genomic tools enabling rapid characterisation of genetic variation to be used in managing both wild populations and ex situ collections of a wide range of plants in botanical gardens worldwide.