During the period from 1930 to 1990, waxy maize
was grown sporadically for production purposes
and researchers concentrated more on breeding experiments.
In the 1940’s at the Agricultural Experimental
Station in Iowa (USA), further and, at the same time,
important properties of amylopectin of waxy maize
were discovered which are similar to those found in
tapioca (Manihot utilissima) (S c h o p m e y e r et al.
1943). Due to the fact that it was not possible to import
tapioca from eastern Asia during World War II, there
was a breakthrough in the use of waxy maize starch
for industrial purposes. The U.S. government launched
a special research programme designed to implement
the starch of this subspecies into different industries.
Thus, research was carried out in the state of Iowa
which was aimed at improving the chemical properties
of maize grain in order to process this grain only for industrial
purposes. Currently, breeding programmes are
still being developed in the USA and they are designed
to improve the genetic line of waxy maize with regard
to its yield-enhancing traits. F e r g a s o n (2001) indicates
that waxy maize varieties are now equal in yield
to ‘dent’ field corn, and average variations in yield do
not exceed 5%. But a real breakthrough in the process
of selection of new varieties over the last 20 years has
been observed in China. In this country, scientists have
undertaken a number of studies to improve grain quality,
including an increase in embryo weight, in order
to enhance the processing capacity of the vegetable oil
and starch industries (D i n g et al. 2006). As a result of
that, both high oil corn (HOC) and high oil waxy corn
(HOWC) have been bred (Table 1).