Under the ITPGRFA’s multilateral system, parties to the Treaty agree to make freely available genetic diversity and related information stored in gene banks concerning, at present, 81 forage species from 29 genera and an undefined number of crop species from 51 genera (covering the vast majority of plant crops consumed by humans but with important exceptions such as cocoa, coffee, cotton, soya or tomato). Breeders and scientists who wish to utilize the plant genetic resources and improve on these varieties are required to seek access in accordance with a standardized material transfer agreement (MTA) (Article 12.4, ITPGRFA). Those who access genetic materials through the system are required not to claim any rights that "limit the facilitated access to the plant genetic resources for food and agriculture, or their genetic parts or components, in the form received" (Article 12.3(d)), ITPGRFA.