Among the Orange Groves of Academe</p>
<p>By PETER MONAGHAN</p>
<p>Riverside, Calif.</p>
<p>A mandarin can never be just a mandarin, nor a tangelo a mere tangelo, for anyone who visits the Citrus Variety Collection with its curator, Tracy L. Kahn.</p>
<p>The confirmed orangophile has, since 1995, managed one of the world’s great living archives of citrus trees.</p>
<p>The collection has two trees each of 1,010 citrus types. They stand in row after row on 22 acres at one edge of the University of California campus here and serve as a resource for research and a safeguard for diversity.</p>
<p>Citrus is a key crop in California, especially in this region, where in the late 19th century, Chinese orchardists brought skills and knowledge from their homeland, a citrus seedbed. In 1910 the Citrus Variety Collection, as part of the Riverside Citrus Experiment Station, began to support the industry. In 1954 the experiment station and the collection became part of the new, Riverside branch of the University of California.</p>
<p>Individual trees in the collection may hold the shriveling fruit of one season and a plump new crop. Beneath the rows lies fallen fruit, rotting or long desiccated.</p>
<p>“Here, try this one,” says Ms. Kahn, for the first of a few dozen times during this day of citrus indulgence and education. Visitors learn that Americans eat an average of 22 pounds of citrus fruit a year. And as Ms. Kahn, an advocate of citrus as much as an expert and connoisseur, explains why the groves are important for cultivation, diversification, and disease prevention, it is hard not to dribble citrus juices down one’s chin.</p>
<p>“What does this taste like?” asks Ms. Kahn, who has out her trusty paring knife. The answer is easy, in the case of Vainiglia sanguigno, a flecked blood orange that she plucks from deep within foliage.</p>
<p>Citrus trees come in many shapes and sizes large, small, squat, or sprawling and some act like vines and crawl along the ground. The fruit are just as varied. Some are as small as peas, while some are as big as a human head. The fruit may be round or oblong, or shaped like chili peppers or drooping pears. The astonishing Buddha’s Hand, which Greek and Roman adventurers brought to Europe from northern India, does look rather like a hand: From its palmlike core, pudgy, wrinkled digits radiate. They earned the fruit another name: fingered citron.</p>
<p>Citrus flesh ranges in color from the not-so-surprising oranges, pinks, and reds to more-startling whites and greens. Some varieties have unlikely fragrances, such as Oxanthera neocaledonica, the tanaka or false orange, which smells like Juicy Fruit gum, and Bouquet de Fleurs, a sour orange that, like many varieties, perfumers have adapted for their products.</p>
<p>The kishu mandarin, from Japan, is cloyingly sweet. Taste the pulp of the Seville sour orange, and it comes as no surprise that it is the favorite of marmalade manufacturers.</p>
<p>Perhaps the weirdest citrus with the most colorful history is the Aegle marmelos, or bael, one of a few varieties that, rather than trickle with juice, ooze with cloying mucus. The Hindu diety Lord Shiva was supposed to have lived under a bael tree. Its fruit is used to treat dysentery.</p>
<p>As Ms. Kahn shows off these characteristics of citrus, her enthusiasm for the subject is palpable, which is impressive because she has conducted many such tours. As she hustles along between rows of trees, she says her fascination with the family of plants took her by surprise during her graduate years here when she took a course from a citrus authority, W.P. Bitters. “I was just excited about the diversity of the flavors and scents and smells,” she says. “I thought citrus would be cool to work on, as a crop.”</p>
<p>Mr. Bitters managed the collection from 1947 until his retirement in 1982 and continued to serve as an informal adviser until he died in 2006 at the ripe age of 90. He liked to play citrus tricks on his students, Ms. Kahn included, like having them taste a trifoliate orange hybrid that, while it resembles a sweet orange, tastes rather like death.</p>
<p>“He would say lots of funny things, too,” recalls Ms. Kahn. Like: “To find your way around a citrus variety collection, you have to follow the scions.”</p>
<p>Now Ms. Kahn has her own research relating to citrus commercialization. She and her colleagues test citrus for “trueness to type” and for commercial potential, and they develop sources of disease- and climate-resistant seed and pollen that researchers and growers around California, and the world, may need. They work with many growers’ groups and rare-fruit hobbyists and assist U.S. Department of Agriculture officers who distribute pollen and other types of citrus germ plasm worldwide.</p>
<p>Scientists at Riverside’s citrus-breeding program have developed several commercial mandarin hybrids, such as Shasta Gold and Yosemite Gold. Their star product is the seedless Tango, a sweet mandarin the size of a clementine, making it ideal for commercialization. It has a smooth, bright rind that increases its consumer appeal. “A million new trees will be planted this year alone,” says Ms. Kahn. “That’s dramatic. It will end up in many high-volume citrus-sales stores. Orders are booked out through 2011.”</p>
<p>When she describes the hybridization that growers pursue or that nature devises for itself, it is clear that citrus varieties may boast evocative provenances. The tangerine, for example, comes from a mandarin that grew near the Moroccan city of Tangiers.</p>
<p>Root stock the few tree types onto which commercial varieties are grafted to achieve healthy growth may have traveled from Kwangtung Province, China, as 12th-century texts reveal. Historical events have interrupted the development of some varieties; the Japanese invasion during World War II disrupted Filipino citriculture. The modern stories may emerge from newer hot spots, such as Chad or Turkmenistan.</p>
<p>In simpler times, eons ago, only three now-eaten citrus types existed the mandarin, the citron, and the pomelo. Under a hot California sun, Ms. Kahn explains how things got much more complicated: She outlines the nature of citrus sex, which is a matter of functional pollen the male parts and ovules the female parts. Still, some varieties, such as navel oranges, have no functional pollen or ovules, but have fruit nonetheless.</p>
<p>Seedlessness fits into this scheme, too seeds are a byproduct of functional pollen, and that, like so many matters of sexuality, has financial ramifications. Increasingly, when it comes to consumer reception, pips are the pits.</p>
<p>The science of citrus propagation is hard to take in while one is slurping the juice of, say, the Oroblanco grapefruit, so I now know why it is a desirable variety but not, despite Ms. Kahn’s efforts, why it took growers 28 years to bring to market.</p>
<p>Yet Ms. Kahn is clearly well practiced at selling citrus. She and her colleagues have often presented the collection at public tasting booths at, for example, campus spring festivals. She has also pitched selections to the campus dining service. “I’ve thought it would be nice to have a permanent juice bar, but you wouldn’t be able to make the same thing every day, because we have only two trees for each variety,” she says.</p>
<p>Any income helps to cover the costs of water, fertilizer, and nonstop care of the groves. A decade ago, Ms. Kahn began to build an endowment. Starting with pocket change, she has been able to double the fund every year, and says that if it continues to grow at that rate until she retires in a decade or so, it should be large enough to secure the collection for at least many years.</p>
<p>She is also working with flavor and fragrance companies that make use of the many appealing properties of citrus. “The collection serves as an inspiration that the companies’ chemists couldn’t get elsewhere,” she says. Manufacturers are alert to citrus colors, tastes, and scents because those appeal to varied tastes. “There are,” notes Ms. Kahn, “162 varieties of Fanta in different parts of the world.”</p>
<p>Given the appeal of citrus, do any Riverside students simply climb the fences and help themselves to so enticing a temptation as 1,010 kinds of fruit?</p>
<p>“Oh, yes,” she says. She confirms it is something she well understands but cannot encourage.
[The</a> Chronicle of Higher Education](<a href=“http://chronicle.com%5DThe”>http://chronicle.com)
Section: Notes From Academe
Volume 54, Issue 38, Page A8