Maize Starch for Industrial Applications - Industrial Crops: Breeding for BioEnergy and Bioproducts - page 175

Fig. 9.3 Waxy production areas in the United States (Based on data from Ref. [ 13 ])
Australia grinds more than 60 k tons of corn annually, utilizing more than 15 %
of the total corn production [ 16 ]. Waxy grain production in Asia is increasingly
being used for food, beverage, and industrial use. A significant portion of the waxy
grown in China and other areas, such as Thailand, is grown as fresh market “sticky
corn.” Waxy grown for the fresh market may be white, yellow, blue, or black and is
harvested in a similar manner as sweet corn and often sold on the ear.
Specialty Starch Hybrid Genetic Resources
The controlling genetic components of the waxy and high-amylose specialty grain
types are starch biosynthetic pathway enzyme mutations. The waxy gene is a
recessive, null mutation of the pathway enzyme granule-bound starch synthase
(GBSS) [ 17 , 18 ]. The amylose-extender gene, responsible for the amylose pheno-
type, is the starch branching enzyme IIb (SBEIIb) [ 19 ].
The waxy-1 gene has been independently discovered numerous times, and many
of the allelic seed stocks are conserved at the Maize Genetics Cooperation Stock
Center (Urbana, Illinois) or the Germplasm Resources Information Network
(Ames, Iowa). The Germplasm Enhancement of Maize program (GEM), begun in
1995 at Iowa State University, has available diverse public domain breeding
materials including a limited number of waxy breeding lines [ 20 ].