BIODIVERSITY E. O. Wilson, Editor National Academy Press Washington, D. C.   1988      CHAPTER pp. 98-105                                   10                               SERENDIPITY IN THE                  EXPLORATION OF BIODIVERSITY                     What Good Are Weedy Tomatoes?                                 HUGH H. ILTIS             Director, University of Wisconsin Herbaium, Madison, Wisconsin           For someone studying natural history, life can never be long enough                                               (Miriam Rothschild, British entomologist,                                                television interview on Nova, 1986).                                                                           Biodiversity is out there in nature, ev- erywhere you look, an enormous cornucopia of wild and cultivated species, diverse in form and function, with beauty and usefulness beyond the wildest imagination. But first we have to find these plants and animals and describe them before we can hope to understand what each of them means in the great biological - and human - scheme of things.     The classification of biodiversity is the job of taxonomists who, born as packrats and inspired by a compulsion to explore and collect the world's biological riches, will risk life and limb to solve the great puzzles of biogeography, ethnobotany, and evolution.    But for most taxonomists these are paradoxical times. Were Alexander von Humboldt or Charles Darwin (two of our godfathers) alive today, they would marvel at our knowledge and technology, and the relative ease with which we can now explore the most inaccessible places, enabling us to bring back biological treasures even from the darkest jungles of Africa and the greenest hells of Amazonia. That's the good news.    The bad news is that the same roads that allow us to drive jeeps into the rain forests or up the highest tundras of the Andes, and the very technologies that land helicopters on the mist-shrouded mesas of Mt. Roraima in Venezuela's Lost World, also bring in a flood of land-hungry squatters, ambitious cattle ranchers, and greedy 98

corporations, often under the auspices of international promoters of development such as the world's  multilateral development banks. All are recklessly destructive of nature and in an orgy of environmental brutality, clearcut forests, burn the trees, and plow up the land to grow more food or graze more cattle, even before any scientist has had a chance to find out what lives there. In the name of growth, progress, and development, and with a colossal self-confidence, we humans are now messing up even the last wilds lands and damming the last wild rivers, oblivious of the irreplaceable biological treasures that are being destroyed.   In short, our twentieth-century civilization still pretty much reflects the short- sighted seventeenth-century pragmatism of Cotton Mather (1663-1728), the witch hunter of Salem, Massachusetts, who proclaimed: "What is not useful, is vicious." But who is to say what is useful and what is not, especially about species not yet discovered that, unknown and unstudied, fall prey to plow or cow? And who can predict the value of a monkey, a butterfly, or a flower? Or of intact ecosystems, to which we are inseparably linked, whether we acknowledge this or not?     Mankind depends on plants for food, fiber, drugs - and a livable world. But more than that, our children will want nature to experience while growing up - to explore, love, and enjoy its beauty and diversity. Corn and cows, concrete and cars are not enough to sustain and empower a human psyche that until only a few generations ago lived in daily contact with a variety of plants and animals, a psyche that, winnowed and sifted by natural selection, is genetically programmed to re- spond positively to nature and its patterns (Iltis et al., 1970; Wilson, 1984). By destroying so much of the natural environment, we humans are now destroying crucial parts of our own psychological as well as physical habitat. For those in the know, it is a gloomy picture indeed.     Like most taxonomists, I am by nature a born collector, first of stamps, then of plants - a botanical adventurer excited by the prospects of finding species no one has ever seen before. Unlike some botanists, I have never had a compelling interest in increasing the world's food supply. After all, is it not now obvious that the world hunger problem cannot be solved by growing more food, but only by growing fewer people, and that more food will always result in still more people, who in turn will devastate ever more nature, inevitably exterminate ever more plant and animal species, and in the long run, make life for themselves and their children ever more difficult? It is then quite ironical that by hunting for the evolutionary origin of potatoes and maize, I was involved in the discovery of two new species of agricultural significance, both splendid examples of wild biodiversity directly useful to humans. THE DISCOVERY OF A NEW TOMATO     In December 1962, Don Ugent (now a botany professor at Southern Illinois University in Carbondale) and I were collecting wild and weedy potatoes and associated plants in the Peruvian Andes for the University of Wisconsin Herbarium at Madison (Iltis, 1982).     For a month we had studied potato populations in the mountains east of Lima to determine how the modern cultigen might have evolved. In fact, its exact origin

is still an ethnobotanical mystery (Ugent, 1970). Was it in Peru, Bolivia, or Chile that people first collected the bitter wild tubers and selected edible potatoes?     We travelled to the Peruvian city of Cuzco by way of a gravelly back road, which crossed the Andes east of Pisco and then traversed above Puquio the vast and unending altiplano, an arid tundra-like grassland called the puna. A cold 3,500 to 4,500 meters above sea level, and therefore often higher than Pike's Peak, the puna is covered with a fantastic collection of cushion plants, including white fuzzy cacti that look like sleeping sheep, all adapted to withstand grazing by domesticated llamas and alpacas and the rare, wild vicunas.     On the eastern slope of these gigantic mountains, within sight of snow-covered peaks, this so-called road (at times not much more than a footpath) dipped dizzily down from 4,260 meters to 1,800 meters at Abancay in only 25 kilometers, then crossed the Apurimac River below Curahuasi (where once stood The Bridge of San Luis Rey of Thornton Wilder's novel), and eventually wound its way up again to the altiplano and on to Cuzco, the capital both of Inca kings and of wild and cultivated potato diversity.     A rest in Abancay was welcome after freezing nights tenting above timbeline and being miserable with siroche (mountain or altitude sickness). On December 21, the early morning was spent packing some 1,500 dried herbarium specimens of the 296 different species collected the week before and getting ready for the push to reach Cuzco in time for Christmas and a hot bath. Then off we drove to the Hacienda Casinchihua in the Rio Pachachaca valley to look for a rare, wild potato species cited by Correll (1962) in a monograph published a short time before.     It was the beginning of the rainy season, and this deep valley was now bursting into bloom. Most memorable were pendent, 4-inch-long, orange trumpet flowers of a Mutisia, a gorgeous daisy named by Linnaeus's son for the eighteenth-century Spanish botanist Don Jose Celestino Mutis.     Above the hacienda, our jeep was soon stopped by a landslide. There was nothing to do but hike along that old Inca road until high above the river we stopped to eat our lunch of avocados, oranges, cheese and small, boiled Peruvian potatoes, yellow and rich in protein.     All around us was a floristic wonderland, full of rare and beautiful plants. In fact, these arid inter-Andean valleys are veritable biogeographic islands, each with many endemic (i. e. unique) species and isolated from other such valleys by wet tropical forests below and cold Andean tundras above, a situation favoring spe- ciation and, hence, biodiversity. In a nearby gully, iridescent green and blue hummingbirds hovered and flitted about, piercing with their bills the cardinal-red flower tubes of a busy sage, Salvia oppositifolia, one of several hundred (!) Andean species of this prolific genus.     So here we spent the rest of the day, always collecting five specimens of each plant - one each for the University of Wisconsin, the University of San Marcos in Lima, and the U. S. National Herbarium in Washington, D. C., and one or two for botanists specializing in that particular plant family, who would tell us exactly what we had collected. This must be done, for there are no accurate, usable books on the 30,000 species of Peruvian plants, a flora so rich it staggers the imagination.

(The northeastern United States is much larger than Peru but has only about 5,000 species of plants; yet here we have many up-to-date botanical compendia called floras by which plant species may be identified.)     Presently we noticed a tangled, yellow-flowered, sticky-leaved, ratty-looking wild tomato, not much different from the weedy tomatillo (Lycopersicon peruvianum) so widespread in Peru. Nevertheless, we took immediate notice of it, for tomatoes belong to the potato family and this was a relative of a cultivated species. And wild or weedy tomatoes must always be taken seriously!     Not only did we collect herbarium specimens of this weedy tomato, describing it in our notebook under the serial number 832 (i. e., the 832nd collection of this expedition), but we also gathered two dozen of its green-and-white striped berries, which are smaller than cherries. We smashed the berries between newspapers to dry their seeds, and weeks later, we mailed them together with other tomato seed samples to Charles Rick, tomato geneticist at the University of California, Davis, who, we had heard, would want to grow them in his experimental plots.     This is an old story, of course, and illustrates the network nature of the study of natural history. Taxonomists do this sort of thing for each other all the time, unasked and as a matter of course, whether they know each other personally or not. "I will collect seeds for you of your special plant, group, if you will collect seeds for me of mine."     Back at the University of Wisconsin, a thank-you-note from Prof. Rick informed us that our No. 832 was most unusual and perhaps useful in plant breeding. Not until 1976, however, after 14 years of research, did Rick (1976) publish this as a new species, naming it Lycopersicon chmielewskii in honor of the late Tadeusz Chmielewski, a Polish tomato geneticist and Rick's associate. Another of our tomato collections, obtained below Curahuasi, he described as yet another new and local species, Lycopersicon parviflorum. That certainly made us feel good: to have been involved in the discovery of two new species in this small though important genus. Previously, taxonomists recognized only seven species of wild tomato, and now there were nine ! Our story could have ended here, of course, and still be a good one, what with us showing off the type of specimens housed in the University of Wisconsin Herbarium to interested students and telling tall expedition tales of haciendas and vicunas, potatoes and tomatoes. But there was more to come. HOW MUCH IS A WILD TOMATO WORTH?    In July 1980, a letter from Dr. Rick told the following story. When 17 years before, he had received our seeds numbered 832, he crossed their progeny with a commercial tomato variety to improve the later's characteristics. After nearly 10 (!) generations of back-crossing the first-generation (F1 ) hybrids, and with subse- quent selection, Rick was able to produce several new tomato strains with larger fruit and a marked increase in fruit pigmentation. But most importantly, they had greatly increased the content of soluble solids, mainly fructose, glucose, and other sugars, all attributes of prime importance to the tomato industry. While the usual type of tomato contains between 4.5 and 6.2% soluble solids, the genes from our

No. 832 increased the content in the new hybrids to 6.6 to 8.6%. In a paper published in 1974, Rick summarized this work as follows:    An attempt was made to combine the high soluble-solids content of ripe fruits of the small, green-fruited Lycopersicon [chmielewskii] with the horticultually desirable charac- teristics of a standard L. esculentum cultivar. By backcrossing from the former to the latter, and by subsequent pedigree selection, pure-breeding lines in which soluble-solids content was elevated to 7-7.5 percent - at least 2 percentage points above that of the recurrent parent - were synthesized (Rick, 1974, Abstract). Parts of Rick's letter to us are worth reproducing:    In our assays of [Iltis and Ugent No. 832 from Hacienda Casinchihua], we discovered that its fruits have a very high sugar content [to 11.5%] as assayed by refractometer readings. Since this species is readily hybridized with the cultivated tomato and the crosses yield relatively fertile hybrids, we initiated a program to introgress the genes responsible for high soluble solids from No. 832 to horticultural lines of [tomatoes. Thus] it was possible to transfer at least some of the genes for this character to produce large, red- fruited lines with significantly elevated sugar content. These derived lines have been widely distributed to tomato workers, some of whom have been exploiting them with the aim of improving sugar content of new tomato cultivars.    The concentration of soluble solids in raw tomatoes is a matter of great economic importance to the processing industry. A number of years ago an expert estimated that each 0.5% increase in soluble solids would be worth about a million dollars. Greatly improved flavor is another benefit. I thought you might be interested in this use of your valuable collection and want to thank you again for you trouble and foresight in sharing it with us.     To make a long story short, and adjusting for inflation to 1987 U. S. dollars, the value to the tomato industry of the genes found in collection No. 832 could, if widely incorporated, be worth about $8 million dollars a year, or, to bask in the glory of larger numbers, about $80 million over a decade!     The yearlong expedition (including the jeep) and 3 years of follow-up research cost the National Science Foundation only $21,000, a small amount in the great scheme of things, and yielded more than 1,000 different numbered herbarium collections, a total of 8,000 specimens now scattered in many major herbaria of the world. In other words, each of our collection numbers cost the U. S. government on the average only $21 (1962 value), including Iltis and Ugent 832 and any of the other species previously unknown to science.     In fact, perhaps the most significant values stemming from our expedition are yet to come, possibly from the high-protein potatoes we collected or from the hundreds of bits and pieces of botanical information we passed along to colleagues, graduate students, and others. But as in the case of our tomato, collected in 1962, commercially utilized a decade later, and not described as a new species until 1976, the practical value of an organism can often not be recognized except after years of work, even for plant groups with known ecomomic use that have been well studied by teams of specialists (which does not apply to most taxonomic groups because of lack of funds to support such large efforts).    For this reason, among others, I have no patience with the phony requests of developers, economists, and humanitarians who want us biologists to "prove" with

hard evidence, right here and now, the "value" of biodiversity and the "harm" of tropical deforestation. Rather, it should be for them, the sponsors of reckless destruction, to prove to the world that a plant or animal species, or an exotic ecosystem, is not useful and not ecologically significant before being permitted by society to destroy it. And such proof, of course, neither they nor anybody else can offer!     The benefits of even the most unimportant research are often quite unexpected. Who could have predicted that these tiny, slimy seeds of a useless, ugly weed, stuck to an old newspaper and costing no more than a few dollars and 30 minutes of our time, might enrich the U. S. economy by tens of millions of dollars - in other words (using 1986 dollars in the calculation), a potential $8 million-a-year gain on a one-time $42 investment? Not bad for a government agency (the National Science Foundation) sometimes maligned for supporting such old-fashioned re- search. Pretty good for a band of field biologists not even wearing white lab coats.     Finally, this discovery is not exceptional. As Rick pointed out, "the literature is replete with examples of the transfer from the [wild species] to acceptable [tomato] cultivars of desirable new traits - mostly resistance to diseases and other pests - often of enormous economic value" (Rick, 1974, p.493). Sweet indeed are the uses of biodiversity! A NEW SPECIES OF WILD MAIZE     The sensational story of Zea diploperennis, a wild species of maize (teosinte) recently discovered in the Mexican state of Jalisco, has often been told (Iltis et al., 1979; Vietmayer, 1979). We cannot here even begin to outline the unlikely events that led a Mexican undergraduate to find this, the fourth species of the genus Zea, which includes maize (Zea mays) - the world's third most important crop with the enormous 1986 global value of more than $50 billion. But although our new tomato was collected through pure serendipity, the diploperennial teosinte owes its discovery to many people, all of whom shared a consuming interest in the Mexican flora and in the mysterious origin of maize (Iltis, 1983).     This story has a very happy ending. Because of the spectacular beauty of the 10,000-foot (2,886-meter)-high Sierra de Manantlan and the potential agricultural value of this rare, perennial, virus-resistant teosinte, which grows here on only 6 hectares and nowhere else on Earth. Mexican botanists and others have worked tirelessly, and successfully, to establish the Las Joyas biological field station of the Universidad de Guadalajara and a 135,000-hectare (350,000-acre) Reserva Biosfera de la Sierra de Manantlan under State of Jalisco and UNESCO Man in the Biosphere (MAB) auspices. The dedication of this enormous reserve on March 5, 1987, by Mexico's President Miguel de la Madrid H. was very gratifying, because the new reserve will now protect the whole, vast, intact biodiversity of that mountain chain, not only the world's only wild populations of this teosinte but also the parrots and jaguars, the orchids and ocelots, the crested guans and giant magnolias, and 10,000 lesser species. Moreover, it will allow all these organisms, including the flagship species Zea diploperennis, to survive in the very environment to which they are

Photo: the author, Hugh Iltis, standing in a field of teosinte.

evolutionarily adapted. In the long run, such in situ (in place) preservation of whole ecosystems in very large nature reserves is really the only effective way these, or any other species, can be assured survival. THE CONTINUING IMPORTANCE OF BOTANICAL EXPLORATION     The new species of tomato and wild maize are just two examples of valuble plants saved in the very nick of time before their minuscule populations faced extinction. And there are tens of thousands of unknown species yet to be discov- ered! Biologists, therefore, must insist that the days of exploration are far from over and that the study of biological diversity, and its preservation in situ, is one of their primary scientific responsibilities.     In the final analysis, the necessary investments in nature preserves and in such noncommercial activities as biological expeditions, herbaria, zoological museums, and training of field biologists (especially in the tropics), inexpensive as these are, are far wiser uses of tax dollars than the billions that are so readily spent on space flights or Star Wars. The Moon and the planets will be out there forever, but the Earth's biological diversity is being exterminated now. It is therefore imperative that we study and carefully preserve nature on this planet now, for this will be our last chance to ensure that biodiversity will survive for future generations. Protection of biodiversity needs to receive top priority in national and international planning. But if nature preservation is to be effective and long-lasting, it must become codified into law and incorporated into ethics and organized religion. Not only biologists and agriculturalists, but every thinking citizen, every responsible politician and re- ligious leader, has here an indispensable role. REFERENCES    Correll, D. S. 1962. The potato and Its Wild Relative. Texas Research Foundation, Renner, Texas. 606pp.    Iltis, H. H. 1982. Discovery of No. 832: An essay in defense of the National Science Foundation. Desert Plants 3: 175-192.    Iltis, H. H. 1983. From teosinte to maize: The catastrophic sexual transmutation. Science 222: 886- 894.    Iltis, H. H., O. L. Loucks, and P. Andrews. 1970. Criteria for an optimum human environment. Bull. At. Sci. 26:2-6.    Iltis, H. H., J. F. Doebley, R. Guzman M., and B. Pazy. 1979. Zea diploperennis (Gramineae): A new teosinte from Mexico. Science 203: 186-188.    Rick, C. M. 1974. High soluble-solids content in large-fruited tomato lines from derived from a wild green-fruited species. Hilgardia 42(15):492-510.    Rick, C. M. 1976. Genetic and biosystematic studies on two new sibling species of Lycopersicon from interandean Peru. Theor. Appl. Genet. 47:55-68.     Ugent, D. 1970. The potato: What is the botanical origin of this important crop plant, and how did it first become domesticated? Science 170: 1161-1166.     Vietmeyer, N. D. 1979. A wild relative may give corn perennial genes. Smithsonian 10:68-79.     Wilson, E. O. 1984. Biophilia, the Human Bond with Other Species. Harvard University Press, Cambridge, Mass. 157 pp.