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Appendix A QPM's Future in the United States This report highlights the potential of quality-protein maize (QPM) for developing nations. However, maize (corn) is the largest crop in the United States, which each year produces more than 100 million tonsâalmost half the world's total. It seems probable, therefore, that any report on a nutritionally improved corn will stimulate considerable local interest. Accordingly, we include this brief appendix to outline some aspects of the crop's domestic promise.1 * * * Although the discovery of opaque-2 corn's exceptional nutritive qualities was made at Purdue University in 1963, so far it has been put to little use in the United States. Moreover, the new, hard- endosperm forms that are known as QPM have not been used here at all. Despite this lack of local recognition, however, QPM could become a noteworthy part of the North American corn industry. Any improve- ment in the fundamental nutritional value of corn is likely to create new, unique, and premium markets. There is, for instance, distinct promise for breakfast cereals and snack foods, both of which are constantly criticized for their low nutritional value. For them, QPM might provide both a nutritious product and an important public relations breakthrough. QPM, however, is not ready for immediate use in the United States. It was created in Mexico with the needs of malnourished people in Africa, Asia, and Latin America in mind. As a result, it is available at present only in open-pollinated types, not the hybrids mainly used in North America. Research is needed to tailor QPM to U.S. environments and farming needs. A research group at Texas A & M University has begun such research with promising early results. In Florida and Texas, their various QPMs have grown well. In 1987, inbred lines with acceptable 1 In this appendix, we use the units most meaningful to American readers involved in farming and agribusiness. For the same reason, we use the name "corn" instead of "maize." 77
76 QUALITY-PROTEIN MAIZE binding value.3 Also, extracting maize endosperms with alcohol might be developed into a visual method to determine the prolamine content.4 OTHER CROPS QPM might be just the opening wedge in an overall upgrading of the nutritional quality of the world's major cereal crops. For wheat and rice, no equivalent genes have yet been found, but scientists working on barley and sorghum have found genes, like those in opaque- 2 maize, that increase the protein quality. These are worth much more study than they are now receiving. Danish researchers, for example, are developing a barley (mutant 1508) that has one of the highest levels of lysine ever measured in a cerealâ5 g per 100 g of protein. From this they have selected a variety (called Piggy) that has 14 percent protein. In its agronomic development, this has reached the point of giving 90 percent of the yield of the best normal-barley varieties. When fed to pigs (without additional protein supplement) it gave growth rates as good as those of commercial swine diets containing protein concentrates.5 The first-discovered high-lysine sorghum has been tested on people in Lima, Peru, but proved to have poor digestibility (45 percent instead of 80 percent) due to its high levels of tannin. Recently, however, it has been noted that the people themselves appear to have overcome the problem by fermenting it with wood ash. This opens up important new possibilities because sorghum has one of the lowest protein qualities of any cereal. The new mutant raises sorghum to about the nutritional quality of wheat.6 3 Information from O.E. Nelson, Jr. 4 Information from CIMMYT's laboratory. 5 Information from Lars Munck, Department of Biotechnology, Carlsberg Research Center, Gamle Carlsberg, Denmark. 6 Information from E. Mertz.