Skip to main content

Currently Skimming:

Nutritionally Improved Maize
Pages 18-34

The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.


From page 18...
... In opaque-2 maize they saw, for the first time, a way to raise the nutritional quality of a vital cereal food. All around the world, maize breeders began transferring opaque-2 genes into local maize varieties, and they enthusiastically rushed the 1 It was named opaque because, when placed over a light box, its kernels appear dark; normal, vitreous maize kernels are transparent enough to allow light to pass through.
From page 19...
... The opaque-2 grain was chalky, not shiny, as is preferred in most regions. Moreover, its ears were small; its yields were 8-15 percent lower than those of traditional maize varieties; it was more susceptible to fungi and insects, both in the field and in storage; and it dried more slowly.
From page 20...
... The main thrust was to use genetic modifiers to harden kernels, to make the endosperm transparent, to raise yields, and to make the grain dry faster. Over the last decade, this approach has brought about a slow but continuous improvement in the qualities that should raise its consumer acceptance, as well as in the traits that should raise its farmer acceptance.
From page 21...
... .6 The basic QPM germplasm now at CIMMYT comprises about 30 experimental populations with widely different adaptabilities, maturities, and grain types. It includes both white and yellow grain types.
From page 22...
... The first feeding test was made with about 3 kg of opaque-2 popcorn. The popcorn was ground and incorporated into a diet containing 90 percent popcorn, 5 percent corn oil, 4 percent mineral mixture, and 1 percent vitamin fortification mixture.
From page 24...
... Nine-year-old Ana Ruth did not know why her aunt had left her in the hospital. But her younger brother had died at home just two weeks before, and her aunt, already overburdened with caring for her own five children, decided to let the University of Valle's hospital worry about the little orphan girl's final care and burial.
From page 25...
... Once she was on a recovery diet, her abnormal hair fell out, and her head began to sprout a fuzz promising a luxuriant growth of silky black hair. Ana Ruth is one of seven critically malnourished children restored to health at the university's hospital.
From page 26...
... CIMMYT's most significant advance in its 16 years of work on QPM has been to overcome this. Today, within the range of experimental error, certain QPM genotypes can equal the yields of the conventional maize varieties now under cultivation in developing countries (figure 3.3)
From page 27...
... gave yields close to those of two hybrids and one open-pollinated variety, all of which are widely used commercially. In trials at more than 20 locations around the world, Mexican QPM varieties have shown yields fully comparable to those of common maize -- the actual performance of seven samples were 98, 110, 107, 105, 100, 97, and 95 percent of the control (see figure 7.2)
From page 28...
... 1 O S a. 50 H 40 30 20 10 Soft-Hard FIGURE 3.4 As maize breeders at CIMMYT took opaque-2 maize through nine generations they changed the preponderance of soft endosperm (clear bars)
From page 29...
... Moreover, with the improved hardness, QPM can be harvested and handled by conventional machinery without the kernels being crushed or cracked. La Posta Pool 25 Pool 24 Amarillo Dentado Tuxpenb-1 Blanco Cristalino Amarillo Cristalino Tuxperfo Caribe Pool 23 Normal Version QPM Counterpart 25 30 PERCENT MOISTURE FIGURE 3.6 The moisture content of normal and QPM versions in the same genetic backgrounds is now essentially identical.
From page 30...
... FIGURE 3.7 The ear-rot resistance of QPM materials has been improving gradually. This results from improvement in kernel phenotype, better drying following physiological maturity, and reduced frequency of genes responsible for pericarp splitting.
From page 31...
... With QPM, storage damage is no worse than in common maize because the endosperm hardness is virtually the same; the excessive incidence of broken kernels and the resulting storage damage has essentially been eliminated. Nutritional Value Over the years of development, the genetic modifications have been accompanied by constant chemical monitoring.
From page 32...
... Although QPM has about the same amount of protein as common maize, it has twice the usable protein because the quality and biological value of its protein is so much higher. For example, the biological value of common-maize protein is equal to about 40 percent of the biological value of milk protein, whereas the 7 Information from A
From page 33...
... Therefore, these results suggest that QPM was almost 50 percent more effective than common maize at fostering growth in these malnourished children. Breath hydrogen excretions were much lower in children consuming QPM than in those consuming common maize.
From page 34...
... Also, there are indications that the yellow-kernel types of QPM may prove unusually valuable in helping to overcome xerophthalmia, a vitamin A deficiency that is the primary cause of childhood blindness in many developing countries. Processed Foods CIMMYT and others have recently studied food products made with QPM.


This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More information on Chapter Skim is available.