ABSTRACT
About one-third of the world’s arable land suffers from chronically inad-equate supplies of water for agriculture, and in virtually all agricultural regions, crop yields are periodically reduced by drought (Kramer, 1980; Boyer, 1982). Global climatic trends may accentuate this problem (cf. Le Houerou, 1996). Efficient irrigation technologies help to reduce the gap between potential and actual yield; however, diminishing water supplies in many regions impel intrinsic genetic improvement of crop productivity under arid conditions (cf. Blum, 1988) as a sustainable and economically viable solution to this problem.
