In 1999, Susan Lin, a bespectacled plant researcher at the World Vegetable Center, in Taiwan, pulled on a pair of latex gloves and got to work cross-pollinating some chili peppers. She collected tiny white flowers from a cayenne-pepper plant, shook their pollen into a tiny test tube, and walked over to an aji-chili plant. Using tweezers, she removed the petals and anthers from its flower buds, exposing the thread-like stigmas that serve as the plant’s female reproductive organs. Then she dipped the stigmas into the pollen, hoping that they would eventually form peppers.
Lin was trying to breed a plant that was resistant to anthracnose, a fungal infection that blisters mature chili peppers with sunken patches that look like cigarette burns. The disease afflicts farms from New Jersey to New Delhi; in India alone, anthracnose was estimated to inflict losses of around four hundred and ninety-one million dollars a year, according to a 2014 paper. But the chilies never emerged. “There were so many flowers, but they never bore fruit,” Lin said. “It wasn’t successful.” In the years that followed, Lin tested more peppers from the W.V.C.’s refrigerated gene bank, which contains heirloom and wild seeds that have been collected from around the world. Finally, the team managed to breed a cayenne-esque pepper, derived from a habanero known as PBC932, that showed resistance to both anthracnose and another fungal infection, powdery mildew. The chilies looked misshapen—Lin called them “very ugly”—but they represented progress.
The world’s supply of fruits and vegetables is at risk. One recent study found that environmental shifts such as climate change, water scarcity, and biodiversity loss could reduce yields by a third by 2050; diseases like anthracnose, which likes hot and humid conditions, are expected to spread as average temperatures rise. Of the eleven hundred vegetable species that are recognized worldwide, about a quarter are in particular danger because they are not preserved in seed vaults. “We see that the diversity out there, in terms of fruit diversity and vegetable diversity, is declining,” Marco Wopereis, the director-general of the W.V.C., told me. “What is triggering that declining diversity is urbanization, industrialization, and the fact that people eat more of the same everywhere.”
The nonprofit World Vegetable Center, which sprawls across two hundred and ninety acres in the dusty suburbs of Tainan, exists to research and breed vegetables that are resilient to climate change, pests, and disease. It houses the largest public collection of vegetable germplasm, or genetic material, on the planet. Its library of Capsicum, the genus of plants that includes hot and sweet peppers, contains more seed samples than any other collection: some eight thousand, or roughly eleven per cent of the varieties held in gene banks around the world. Some of the W.V.C.’s seeds are more than twenty years old. Because germination rates decline over time, even in controlled conditions, Lin and her colleagues are constantly growing the seeds out, harvesting them, and putting them back into storage, to insure the vitality of each line.
On a recent Thursday afternoon, Lin, looking buoyant in a white T-shirt and a floppy beige hat, led me through half an acre of bejewelled pepper plants at the W.V.C., where she and her colleagues are currently conducting experiments. A riot of colors and fragrances—three hundred plants in all, each from a different variety—surrounded us. At a bush of vermillion chilies, which are among the hottest in the world, Lin plucked one, snapped it open, and placed it in my palm. “Just smell it,” she warned, in Mandarin. “Don’t eat it.” One whiff, a swirl of zest and rocket fuel, made my eyes water. I dropped the chili, and Lin giggled sympathetically.
Lin showed me royal-purple peppers, chocolate-hued habaneros, and miniature white chilies. Some were bell-shaped and others looked like tiny, glossy pumpkins; some smelled of green-apple candy and others had a distinct floral kick. One canary-yellow pepper, roughly the size of a pearl, was named the tepÃn, after the Aztec word for “flea.” Lin told me that it would blow out my taste buds, and she was right.
Later, Lin told me what had happened to her resilient ugly chilies. In 2004, she was out in the field when she noticed something that made her heart drop: lesions had appeared on her peppers. “I took it to the pathology department and asked what happened,” she told me. The lab concluded that the disease-resistant gene in PBC932 peppers had lost its edge. “The gene was from a seed collected from 1991,” she said. “By then it had been over ten years. The fungus in the field had mutated.” The evolution of anthracnose had nullified several years of scientific work. But the experience was also instructive, Lin told me. Crops exist in ecosystems that are always changing, and breeding them for survival can be a moving target.
The world’s first peppers probably sprouted from the lowlands of what is now Brazil. According to a study, the seeds of wild chili peppers are often spread by birds, which do not have heat receptors in their mouths. More than six thousand years ago, humans domesticated peppers, and in the late sixteenth century maritime trade routes carried them to Asia, where most chilies are grown today. “When you take a crop from where it originated, and you take them to a new place, they often do better,” Paul Bosland, a Regents Professor of horticulture and a co-founder of the Chile Pepper Institute at New Mexico State University, told me. Today, many cuisines—Thai, Indian, Mexican—would be unrecognizable without peppers. In Bhutan, some families consume more than two pounds a week.
Taiwan did not set out to train an élite team of pepper breeders. “Initially, they just wanted to have the world’s largest collection of mung beans,” Angel Jeng, the W.V.C.’s social-outreach coördinator, said when we met in April. After the technological innovations of the Green Revolution increased crop yields around the world, the U.S. Agency for International Development called for an institute that could increase access to vegetables in Asia, a region that still suffered from malnutrition. In 1971, the U.N. General Assembly voted to admit the People’s Republic of China and to expel Taiwan. Funding from international partners faltered; some thought it might be problematic to situate the institute in Taiwan, which most countries view as a self-governing territory, not a nation. In the end, however, Taiwanese lawmakers agreed to provide much of the center’s funding, and it opened in 1973. “Taiwanese planners turned to science as a way to regain a semblance of regional and global power,” James Lin, an international studies and history professor at the University of Washington, told me. The W.V.C.’s pepper-breeding team was established in 1986.
Although dozens of chili species grow around the world, the majority of the ones we eat, whether sweet, savory, or spicy, were bred from just five species. (They are not related to black pepper, which comes from the stone of peppercorn vines.) In general, sweet peppers are sensitive to hot weather, but other chilies are relatively sturdy. Some wild chilis can withstand temperatures of up to a hundred and ten degrees Fahrenheit; long, warm days and drought actually make their peppers spicier. NASA scientists have even grown a pepper plant in space. Still, the resilience of peppers has a limit. “As things get drier and hotter, pepper production gets more difficult and approaches impossible,” Derek Barchenger, who has directed the pepper-breeding team since 2017, told me.
When I met Barchenger for coffee in the W.V.C. cafeteria, he was looking distinctly American in a plaid shirt, black-rimmed glasses, and a thick brown beard. (He grew up in Oklahoma.) A research assistant on the pepper team, Hank Lin, joined us. Taiwan has the ideal hot and humid climate for their research, they told me, and is a strategic location for peppers in particular. “Seventy per cent of pepper production occurs in Asia, seven and a half per cent in the Americas,” Barchenger told me. “To get to our main clientele, we have to work in Asia.” India is the pepper team’s biggest market; more than half a million Indian farmers grow tomatoes and peppers developed by the center. Barchenger often travels to W.V.C.’s regional offices in India, Thailand, Tanzania, and Benin.
What Taiwan does not have, Lin and Barchenger went on, is a large community of chili-lovers. In Taiwanese food, peppers more commonly lend color than flavor; only the mildest varieties tend to be sold at the market. For this reason, Barchenger was the only member of the four-person pepper research team who grew up loving hot peppers. Lin, a self-described eater, considers them an acquired taste. “You’re increasing your tolerance slowly over time,” Barchenger told him.
“I follow Derek in the field and taste a lot of chili,” Lin agreed. “I’m learning how to appreciate spicy food.”
“Susan can’t,” Barchenger added with a laugh. “We’ll find something very spicy and she will start screaming in the field.”
Taiwan’s aversion to chilies has an unexpected benefit for researchers. In countries where peppers are endemic or have a longer history, diseases like bacterial wilt and phytophthora often cut into yields. “When you have huge acreages of production, then the pathogen populations build up and evolve and mutate,” Barchenger told me. “But here it is very sporadic. As an island, we’re isolated from other continents.”
In April, the W.V.C. hosted horticulturalists from Latin America and the Caribbean for a two-week plant-breeding workshop, which was funded by Taiwan’s Ministry of Foreign Affairs. Most of the attendees came from the minority of countries that have diplomatic relations with Taiwan: Belize, Guatemala, Haiti, Paraguay, Saint Kitts and Nevis. One afternoon, the participants toured the giant walk-in refrigerator that serves as the center’s gene bank. Hundreds of thousands of aluminum seed bags, each one labelled with a barcode or QR code, which contains the information on the species, lined the shelves.
“Welcome to one of the most diverse hot spots of vegetables in the world,” Maarten van Zonneveld, a tall Dutch scientist who oversees the gene bank, told the group. A Belize-based biotechnologist, Omaira Avila Rostant, murmured her appreciation: “Beautiful, no?” When scientists manage to grow resilient varieties from these seeds, van Zonneveld explained, the W.V.C. offers them to research institutions, companies, and farmers around the world. It charges a small fee to partly cover the costs of processing and shipping.
At another workshop session, the visitors suited up in disposable blue gloves, knee-high rubber boots, and hats to protect against the sun. Barchenger led the group to some pepper plants that his team was growing for the Asia and Pacific Seed Association, whose yearly consortium brings together plant scientists, government officials, and seed companies. “We do all of our basic research here,” Barchenger told the group. “When a line is finished, we send it to wherever the target market is.” He instructed his visitors to pluck some wilted leaves from a few unhappy-looking plants, so that they could study them at a diagnostic session later that day. As outbreaks intensify in a changing climate, farmers will need to identify pathogens quickly and accurately if they hope to protect their crops.
The Quest to Save Chili Peppers from Climate Change
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