The Project includes four main components: the prioritization of crop wild relatives based on gap analysis, the collection of CWR in the field, CWR conservation in genebanks, and the use of CWR in pre-breeding efforts to prepare them for use by crop breeders.
The first phase of the Project focused on the development of a global CWR inventory, an occurrence dataset, and gap analyses detailing where CWR species have not been collected before. This initial research step helped to identify and prioritize which CWR to collect and where, based on a global dataset of past collections, expert evaluations, and information on ease of use in breeding for each species according to the Harlan and de Wet (1971) genepool concept.[i] The CWR inventory covered approximately 193 crop genepools, while gap analyses were carried out for 81 genepools. The Project team identified and prioritized the closest CWR taxa of the 29 focal crops for collection, and these taxa were used to identify key countries for collecting.
CWR have to be collected from the wild before they can be used in breeding. Collecting is a time-consuming process that requires planning as well as perseverance and determination in the field. In this Project, national partners organize collecting of priority CWR in their country. For example, collecting in Georgia takes place as a collaborative effort between the National Botanical Garden of Georgia and the Institute of Botany of Ilia State University. Prior to collecting, permits have to be obtained, and localities of populations identified. Once found, collectors may need to visit the site several times to ensure that enough plants are flowering and the seeds are of high enough quality for collection.
Once crop wild relatives have been collected, conserving them properly in ex situ collections is essential to ensure their continued availability for breeding and to safeguard their genetic diversity from extinction in the field. All crop wild relatives collected as part of this project will be conserved in the national collections of the country of origin, the Millennium Seed Bank, the appropriate CGIAR international collection, and the Svalbard Global Seed Vault. In genebanks, CWR seeds are stored for the long-term at -20° C. They can be requested for use in breeding and research.
Using crop wild relatives in crop improvement is a long and laborious process that is typically much more difficult than using cultivated crop varieties. Many plant breeders avoid the use of crop wild relatives for this reason. The first step is using CWR in crop improvement is pre-breeding, an essential component of the Project consisting of a wide range of activities that aim to isolate desired genetic traits (e.g., disease resistance) and introduce them into breeding lines that are more readily crossable with modern, elite varieties. Early on, the Project launched two pilot pre-breeding studies: one for rice in collaboration with the International Rice Research Institute and Cornell University, and one for sunflower in collaboration with the University of British Columbia. Since then, a number of other pre-breeding projects have started, and are expected to eventually cover some 20 crops in all.