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Suggested Citation:"Research Needs." National Research Council. 1988. Quality-Protein Maize: Report of an Ad Hoc Panel of the Advisory Committee on Technology Innovation Board on Science and Technology for International Development National Research Council, in Cooperation With the Board on Agriculture National Research Co. Washington, DC: The National Academies Press. doi: 10.17226/18563.
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Suggested Citation:"Research Needs." National Research Council. 1988. Quality-Protein Maize: Report of an Ad Hoc Panel of the Advisory Committee on Technology Innovation Board on Science and Technology for International Development National Research Council, in Cooperation With the Board on Agriculture National Research Co. Washington, DC: The National Academies Press. doi: 10.17226/18563.
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Page 73
Suggested Citation:"Research Needs." National Research Council. 1988. Quality-Protein Maize: Report of an Ad Hoc Panel of the Advisory Committee on Technology Innovation Board on Science and Technology for International Development National Research Council, in Cooperation With the Board on Agriculture National Research Co. Washington, DC: The National Academies Press. doi: 10.17226/18563.
×
Page 74
Suggested Citation:"Research Needs." National Research Council. 1988. Quality-Protein Maize: Report of an Ad Hoc Panel of the Advisory Committee on Technology Innovation Board on Science and Technology for International Development National Research Council, in Cooperation With the Board on Agriculture National Research Co. Washington, DC: The National Academies Press. doi: 10.17226/18563.
×
Page 75
Suggested Citation:"Research Needs." National Research Council. 1988. Quality-Protein Maize: Report of an Ad Hoc Panel of the Advisory Committee on Technology Innovation Board on Science and Technology for International Development National Research Council, in Cooperation With the Board on Agriculture National Research Co. Washington, DC: The National Academies Press. doi: 10.17226/18563.
×
Page 76

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9 Research Needs As pointed out earlier, there is still much to be done before QPM can achieve its potential worldwide. Some general funding needs are: • To sustain basic QPM research at Centro Internacional de Me- joramiento de Maiz y Trigo (CIMMYT); • To extend and sustain the programs at other institutions collab- orating with CIMMYT; • To begin integrating QPM into national programs, including support for in-country adaptive evaluations (including postharvest handling); • To create a "pipeline" for the tons of seed needed for commercial use; and • To support national breeding programs to develop QPM for their individual conditions. IN-COUNTRY RESEARCH Overall, the next requirement is to intensify the testing and selection of QPM in suitable areas of need. This, in itself, is a demanding enterprise, and it is urgent that Third World countries develop national programs to collaborate with CIMMYT to evaluate QPM materials for local use. Effective seed production is vital to the ultimate success of any new crop introduction, and even more so to QPM, in which the vital gene is recessively inherited. The effective delivery and marketing of seed, and the maintenance of genetic purity, are all critical in creating a local industry. REGIONAL RESEARCH NEEDS As previously noted, QPM should fit particularly well where diets are highly dependent on maize or root crops; for example, in parts of 72

RESEARCH NEEDS 73 Brazil, the Andean region, Central America, Mexico, coastal West Africa, Central Africa, Ethiopia, Kenya, Malawi, Mozambique, the outer islands of Indonesia, Vietnam, and the Philippines. Research to adapt the crop to these regions is needed. In particular, to be useful in many areas of Africa, QPM must be improved for resistance to streak virus. (This is true of normal maize as well.) Resistance to downy mildew should also be developed in QPM to make it more beneficial for Asian countries where this fungal disease is serious. FIELD STABILITY Remaining questions about QPM's field stability, protein quality, and endosperm expression would best be answered by more definitive research, especially outside Mexico. Most of the work done so far has been in Mexico, where over the years the process of selection has produced QPM varieties that behave predictably year after year. In international testing, however, some QPM populations seem to be strongly influenced by climate and do not behave as expected. This is true of all crop varieties, but in the case of QPM, the instability of the gene modifiers adds an additional uncertainty to be studied, codified, and overcome. The question of how to maintain QPM's genetic purity in commercial production is also a concern. More definitive evaluation should be made to establish the cheapest and easiest methods both for maintaining genetic purity in production fields and for monitoring protein-quality levels in commercial practice. A method under consideration is the introduction of yellow QPM in areas where white maize is used and white QPM where yellow maize is used. Also, there is the possibility of creating hybrid QPM varieties that would not be contaminated because of genetic incompatibility with other maize varieties. GENETIC RESEARCH More basic work on the genetics of modifiers is needed. The wide array of QPM germplasm can now be employed to improve under- standing of their behavior. Efforts should also be made to identify simply inherited modifiers for inbred conversion programs. These (1- or 2-gene) simply inherited modifiers—if they exist—would make the process of creating and perfecting QPM much easier. Another research area is to develop varieties of QPM that will not cross with normal maize, thereby eliminating the possibility of genetic contamination.

74 QUALITY-PROTEIN MAIZE Molecular geneticists could benefit QPM's development enormously by resolving basic genetic uncertainties relating to the modifiers. Since modifiers are inherited quantitatively, it is important to know how many modifier genes are involved and where these are located. If the opaque-2 gene and its specific modifiers could be identified, their transfer to other genetic backgrounds would be greatly facilitated.1 HYBRIDS In most maize-producing regions there is the opportunity to grow both hybrids and open-pollinated varieties; however, countries that now rely on hybrids would find the switch to QPM much easier if it is available in hybrid form. Indeed, for most such countries, QPM is unlikely to be successful unless hybrid performance is satisfactory. Information on the combining ability of CIMMYT's QPM germplasm should be compiled to facilitate the development of QPM hybrids. VARIETIES FOR TROPICAL HIGHLANDS In some parts of the world, the soft-endosperm, floury maizes are preferred. This is particularly true in the highlands of Bolivia, Peru, and Ecuador. For such regions, work should be intensified to produce suitable germplasm having large floury kernels with good resistance to ear-rot pathogens. MODIFYING AMINO ACID PROFILES Opportunities exist for further increasing the proportions of proteins that carry the most desirable amino acid patterns. For example, the prolamine protein fraction in today's QPM stocks comprises approx- imately 30 percent of the protein. If this could be further decreased, the lysine, tryptophan, and biological value would rise to even higher levels than in today's QPM varieties. Low levels of prolamines have been found also in high-oil, opaque- 2 maize. For example, in one variety (designated R802, a high-oil opaque-2 inbred type) the percentage of prolamine (actually zein) in the whole-kernel protein is down to approximately 22 percent.2 This suggests that further improvement in both protein quality and food 1 A start on this has been made. See, for example, Schmidt et al., 1987. 2 Alexander and Creech, 1977.

RESEARCH NEEDS 75 energy (from the high oil content) of the whole grain can be expected. Appropriate breeding schemes deserve to be directed towards that end. NUTRITION RESEARCH Some specific needs are: • Testing QPM in local food products in the regions where they are consumed; • Testing QPM in nutritional supplements, such as Incaparina; • Testing QPM in refugee-feeding programs; and • Testing the acceptability for human consumption and industrial use on a large scale. Some general research needs follow: Creating indigenous foods using QPM. A major feature, not yet adequately addressed, is the acceptance of QPM for preparing maize- based foods such as tortillas, arepas, porridges, and gruels in actual local situations. It is known that these products can be made, but whether they have subtle differences that will affect local preference is uncertain. Fortifying foods with QPM. Using QPM to fortify baked products seems to be a good approach for maize-producing countries that now import protein supplements to fortify foods. This is a common situation in many Latin American countries. Developing QPM concentrate. The production of QPM concentrate (from which the starch has been removed) deserves attention. The process has yet to be perfected. Also, comparisons with soybean meal need to be conducted. Foods that could be fortified include: weaning foods, instant tortilla flours, tamalitos, and foods for nursing mothers. CHEMICAL ANALYSIS RESEARCH There is a need to create simple tests for quality protein that can be used in the field or at checkpoints to identify adulteration with common maize. Dye-binding with Acilane Orange G shows some promise because there is a correlation between amino acid content and dye-

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 cereal—5 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.

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