Bilateral agreements adopted under Article 15 of the International Treaty on Plant Genetic Resources for Food and Agriculture, which call for agreements between the treaty`s governing body and the International Agricultural Research Centres of the Advisory Group for International Agricultural Research (CGIAR), in which there are ex situ collections of plant genetic resources for food and agriculture of fiduciary origin. The exchange of letters, which constitutes an arrangement for the application of the exchange of letters of 15 March 1991, and constitutes an agreed note for the interpretation of the FAO headquarters agreement of 31 October 1950 with the agreement on the headquarters of the World Food Programme. Rome, 15 March 1991 In view of the above, the Italian government, by Law 506 of 3 November 1988, has generously agreed to take over and finance a project to build additional housing on the Terme di Caracalla site. The restructuring of the Caracalla complex will help solve the problem of adequate accommodation for the future. However, in the meantime, the organization is still renting additional offices on the private market to meet its temporary requirements for accommodation in headquarters and could be placed in a similar situation at some point. If this proposal is acceptable, I also propose that this letter and your affirmative answer, written in English and Italian, as well as the agreed lists, also in both languages, constitute a complementary agreement within the meaning of Article I, paragraph l, paragraph f) (ii) of the siege agreement, with the English and Italian texts also referring. The headquarters agreement signed in Washington on 31 October 1950 shows that adequate arrangements are being made to meet the needs of FAO`s new headquarters as part of the Organization`s development. For this reason, Article I, Section 1, Point f) (ii) while detailing in Appendix A of the agreement the land and buildings within the scope of the concept of “central seat”, in particular the conclusion of complementary agreements, including other lands or buildings, within this scope.