from R&D Innovator Volume 3, Number 6
Year’s Card Leads to Newly Discovered Species of Enormous
Iltis is professor emeritus of botany at the University of
Wisconsin-Madison, and director emeritus of the university’s
herbarium , a collection of about one million dried plant
specimens used to catalog and identify plants.
early 1976, I sent a large New Year's card, really a poster, to
botanists around the world, following an annual tradition of our
herbarium at the University of Wisconsin to keep friendships
alive, and to cajole, inspire, and arouse my taxonomic colleagues
to their environmental responsibilities.
A confirmed plant-lover and hard-line preservationist, I am
awed by the beauty, elegance and usefulness of the plant kingdom,
and the (undoubtedly inherited) human need for contact with
the overall goal of my annual message is to help restrain the
steady, worldwide march toward environmental degradation in the
name of "progress," I never expected this mailing to
lead—in an exquisite example of scientific serendipity—to
perhaps the most important discovery of my scientific career.
poster features a plant that--for one reason or another--I
consider significant. The
1976 edition portrayed my drawing of Zea
perennis, a perennial grass, one of several corn relatives
that Mexicans call "teosinte," the "grain of the
gods." As an
expert on the evolutionary origins of corn (Zea
mays), I'm fascinated by the structural changes that occurred
when teosinte evolved into corn, hence every one of the four
species of the genus Zea
is important to me. Furthermore,
wild crop relatives supply plant breeders with new genes which
allow crops to adapt to new conditions, and since corn is the
third-largest crop on the planet (worth $65 billlion worldwide in
1993), teosintes may well turn out to be critical to the global
food supply. (To be
quite clear, though, I see the problem not as one of growing more
food, but as one of growing fewer people!)
perennis had last been seen in the wild in 1921 at its only
location, in Western Mexico, by two U.S. Department of Agriculture
botanists, who introduced it to university greenhouses, including
ours at UW. Since I,
and other botanists, had tried to relocate the wild population and
failed, I wrote "extinct in the wild" next to the
drawing, mailed off some 250 posters, and went back to my other
attention was forcibly returned to the teosintes two years later,
when I received a handwritten note from a man who worked for a
messenger service in New York city. "I know little about corn," wrote Anthony Pizzati.
Nonetheless, he said, a Mexican friend had found "perennis…
the long-lost original corn."
Pizzati concluded with a question that, for the beauty of
its understatement, made me laugh. "What do you think--interesting?"
reasoned that Pizzati could only be referring to Zea
perennis, so I directed a graduate student, John Doebley, to
answer his letter (what else are graduate students for?) and see
if we could get some seeds and find out what Pizzati was really
we go further, I should explain a little about the
"old-fashioned science" that has consumed my
career--taxonomy--the classification and naming of living
organisms. In this
age of gleaming molecular laboratories, available only to those
who have survived endless technological training, field taxonomy
must seem rather quaint. Yet without such taxonomy, Charles Darwin would not have
recognized the principles of evolution--and thus not initiated the
greatest intellectual revolution of all times.
Literally speaking, without taxonomy, evolutionary
biologists can't know what they are talking about.
"Nothing makes sense in biology except in the light of
evolution," said Theodosius Dobzhansky, the great Russian
in the late 20th century, as in Darwin's time, we field biologists
take our clues wherever we can.
We get help from the oddest sources--often from people
we've never heard of. And
we stay in touch, because we need each other.
I later reconstructed the events, my poster had been placed on a
bulletin board at the University of Guadalajara by the local
taxonomist, my friend Luz Maria Villareal de Puga, who, slightly
irked, had urged her students, "Go and find this teosinte,
and prove that gringo Iltis wrong."
Puga's forthrightness fired up Rafael Guzman, one of her
undergraduate students, to hunt for this Zea
perennis. Guzman went to the original locality in the mountains of
Jalisco, a state in Western Mexico which runs from the Pacific
coast to the Sierra Madre de Sur and over to the capital city,
Guadalajara. By the second day, directed by a knowledgeable campesino,
he'd dug up a sterile plant and, back at the Universidad de
Guadalajara, it proved, in the next two months, to grow into the
long-lost Zea perennis.
Even Better Finding
is a persistent, determined fellow.
Most students might have stopped at that point,
satisfied to have refuted the Norteamericano expert —but
not Rafael. Within a
month, he learned from a fellow student that Zea
perennis was growing in another location.
Guzman located that population and sent me seeds (by this
time, we were in contact by mail).
When grown in Wisconsin, this teosinte turned out to be not
only a perennial, but, one with half the number the chromosomes.
It was a totally new species, and we soon named it Zea
Zea perennis, this species freely interbreeds with corn, which
raised the possibility that the crop could be grown for several
years from one rootstock. If
corn could be grown as a perennial, like apples or hay, it would
lead to a tremendous savings in soil erosion and an improvement
for the farmer’s bottom line.
The discovery was promising enough to earn coverage on the
front page of The New York
Zea diploperennis has an attribute which I consider much more
significant: U.S.D.A. specialists in Wooster, Ohio, showed that it
is immune to, or tolerant of, seven corn viruses, and is the only member of Zea
that is immune to three of them.
As if to demonstrate how wild relatives supply raw material
to plant breeders for improving crops, Zea
been studied by every seed corn company in the country, and its
immunity has already been transferred into corn, at least in South
Potentially Valuable Species
since I'm a conservationist and preservationist, to me the most
important echo of that challenging New Year's poster was the
establishment in 1987, after eight years of frantic talking,
writing, and outright pleading, of the 350,000 acre Sierra de
Manantlan Biosphere Reserve, under the direction of the University
of Guadalajara. What
with Zea diploperennis scattered on some 900 acres of the reserve, and
nowhere else in the world, this became the first reserve
established principally for the preservation of a wild crop
Sierra de Manantlan reserve stretches up from tropical forests at
the base, to oak and oak-pine on its slopes, and cloud forests on
the top. Its
biological diversity is enormous:
although the reserve is only about 1 percent of the size of
Wisconsin, it has one-third-again as many higher plant
this botanical treasure-house is threatened by increasing
population pressures from neighbors who depend on it for wood,
pasture, and water.
final result of that not-quite-accurate New Year's poster was to
start a long, fruitful collaboration between University of
Guadalajara and the University of Wisconsin, in which more than a
dozen students have come here, many, including Rafael Guzman,
for advanced degrees.
have I learned from all this?
With botanical exploration, you can never tell what
you’ll find---or where you’ll find it.
Genetics, now almost the archetypal high-tech science, is
still dependent on information that plants and animals have been
storing up since the beginning of life. When we need a corn that resists a new leaf blight or virus,
we may be forced to turn to the "living library" of corn
relatives, the teosintes. And
if we allow that library to be destroyed--or if we stop
communicating with the people who know where the "books"
live and what they contain--our children may be faced with
disaster that they will not be able to survive.
Carol Bartz, the CEO of Autodesk, Inc., a software company, said
recently, "Most of us are put on this Earth to do one simple
thing--and that is to be a good ancestor."
Both from a biological and moral standpoint, we cannot,
must not, do less.