edited by David F. Nygaard, Peter L. Pellett ; sponsored by the International Center for Agricultural Research in the Dry Areas (ICARDA) and the United Nations University (UNU)
presented at a symposium held May 6-9, 1979, at the Beltsville Agricultural Research Center (BARC) ; organized by the BARC Symposium IV Committee ; sponsored by the Beltsville Agricultural Research Center ; Gary R. Beecher, editor