Seeds of Significance
Corn of the Past Answer Questions
of the Future
by Erin Dyer
 Everything old is new again, so
the saying goes. Even with corn.
And, as it turns out, UT's McClung Museum is participating in research
that, by unraveling the environmental and genetic history of corn, may contribute
to development of modern corn types that can tolerate more diverse growing
conditions.
McClung Museum houses one of the largest and most important collections
of native prehistoric food plant remains in eastern North America. By studying
the changes in these ancient species, some of which were in use 4,000 years
ago, researchers are looking to find how these plants may play genetic and
ecologic roles in food crops in the future.
The beginnings of the McClung's prehistoric plant collections date back
60 years to the excavation of prehistoric sites in association with Tennessee
Valley Authority and Works Progress Administration (WPA) projects in the
Tennessee valley. Decades of additional archaeological field work have resulted
in a documented 2,000-year relationship between people and corn in the valley.
Dr. Gary Crites, the museum's director of ethnobotany, decided to find
out just how extensive the museum's corn collection is and from which time
periods and cultural contexts corn had been recovered. He is attempting
to document changes that have occurred in corn in the region through time.
For the past three years, the research has been funded by a grant from
the Raymond F. and Mary Baker Endowment through the Iowa State University
Foundation. The goal is to inventory and stabilize the corn collection and
develop a baseline description of corn from different time frames.
The research is imperative to future studies on such collections anywhere
in the world, Crites explained. Today's increasing conservation ethic means
that archaeological excavations, in the traditional sense, will not be as
prevalent in the future. He added that collections already in existence
and which have been well excavated and documented are going to be the research
material for the future.
One issue researchers face is disagreement about the origin of corn.
There are two major competing theories. The most widely accepted theory
has been that corn was derived from a mutation in a grass from Mexico called
annual teosinte (Zea mexicana). The major competing theory contends that
an ancient cross between what is now a rare perennial teosinte (Zea diploperennis)
and gamagrass (Tripsacum dactyloides) yielded both corn and annual teosinte.
Crosses of these two grasses by Mary Eubanks, a Duke University research
colleague of Crites, yielded a hybrid that is virtually identical to the
oldest examples of corn known. This hybrid, named Tripsacorn, is now patented.
The implications of this successful cross are tremendous. Genetic diversity
in hybrid corn is rather limited, which tends to increase the likelihood
of a population crash in times of stress (introduced by pests, disease,
or environmental change). Traditionally, when crops have been threatened,
researchers and farmers have turned to the germplasm of old, open-pollinated
varieties which often contain natural resistance to pests and diseases in
particular environments. Germplasm from these old races or varieties can
be infused into hybrids to build resistance to pests and diseases and enhance
success in a particular environment.
Tripsacorn has a natural resistance to rootworm, which costs American
corn farmers a billion dollars per year. Another potential advantage of
the cross between teosinte and Tripsacorn is lower maintenance costs compared
to many hybrids. Because Tripsacorn may be more tolerant of varying weather
conditions, it might be productive in more diverse environments. Also, since
the parents of Tripsacorn are perennials, there is a possibility that perennial
corn plants may be in our future.
Crites hopes their research can make a contribution to understanding
how corn has adapted to this part of the world over time and what its potential
is toward moving corn into more diverse habitats.
"If it turns out the gamagrass and the perennial teosinte really
work, it could be the beginning of another green revolution where science
is able to make a quantum leap in the
production of food," he said. | 