#103 from R&D Innovator Volume 3, Number 6           June 1994

New Year’s Card Leads to Newly Discovered Species of Enormous Economic Potential
by Hugh Iltis, Ph.D.

Dr. 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.

In 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 nature. 

Since 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.

Each 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!)

Zea 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 duties. 

Found—Again!

My 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?" 

I 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 talking about.

Before 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 biologist.

Now, 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.

As 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."

Maestra 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.

An Even Better Finding

Rafael 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 diploperennis. 

Unlike 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 Times. 

But 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 diploperennis  has been studied by every seed corn company in the country, and its immunity has already been transferred into corn, at least in South Africa.

Saving Potentially Valuable Species

But 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 relative. 

The 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 species--2,650.  But this botanical treasure-house is threatened by increasing population pressures from neighbors who depend on it for wood, pasture, and water. 

The 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. 

What 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.

As 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.