Identifying relevant sources of genetic variation

The options are (probably in this order of preference):

• Locally released varieties
• Your own breeders' lines
• Breeding lines produced by international programmes
• Local landraces
• Varieties released by breeding programmes in other countries
• Germplasm bank accessions

Note that because of international regulations governing the exchange of germplasm, it can be a lot easier to obtain material from a germplasm bank than from other programmes in other countries.