UC Davis researchers help find birthplace of chili pepper

Somewhere between Puebla and Veracruz in central-east Mexico rests the cradle of culinary inspiration: The birthplace of the domesticated chili pepper.

That’s the determination of an international team of researchers, led by a plant scientist at the University of California, Davis.

That fact is more than an interesting tidbit to spice up dinner conservation. Chili peppers now rank as the world’s most widely grown spice crop.

Rather than one geographically specific spot, the birthplace belongs to a fertile pepper-friendly region, determined the researchers. Extending from southern Puebla and northern Oaxaca to southeastern Veracruz, that region is further south than was previously thought, the researchers found. It’s also very different than the origin of common bean and corn crops, which are believed to have been domesticated in Western Mexico.

The team used a four-pronged investigation, based on linguistic and ecological evidence as well as more traditional archaeological and genetic data.

The study findings will be published online Monday — the day before Earth Day — in the Proceedings of the National Academy of Sciences, as part of a series of research papers on plant and animal domestication.

Understanding the path of the pepper can help scientists (and farmers) better understand the process of domesticating wild plant and animal species through selective breeding.

“Identifying the origin of the chili pepper is not just an academic exercise,” said UC Davis plant scientist Paul Gepts, the study’s senior author. “By tracing back the ancestry of any domesticated plant, we can better understand the genetic evolution of that species and the origin of agriculture — a major step in human evolution in different regions of the world.

“This information, in turn, better equips us to develop sound genetic conservation programs and increases the efficiency of breeding programs, which will be critically important as we work to deal with climate change and provide food for a rapidly increasing global population,” he added.

In addition to its unexpected findings, how this study was conducted proved ground breaking, too, said study co-author Gary P. Nabhan, an ethnobiologist and agroecologist at the University of Arizona’s Southwest Center.

“This is the first research ever to integrate multiple lines of evidence in attempts to pinpoint where, when, under what ecological conditions, and by whom a major global spice plant was domesticated,” Nabhan said. “In fact, this may be the only crop-origins research to have ever predicted the probable first cultivators of one of the world’s most important food crops.”

Genetic evidence had led plant researchers to think the domesticated pepper originated in northeastern Mexico. But other research — including linguistics — moved the birthplace much farther south. Among the clues were historical language references and a search for the earliest words used for cultivated chilies.

Other researchers on the study were Kraig H. Kraft and Robert J. Hijmans, both of UC Davis; Cecil H. Brown of Northern Illinois University; Eike Luedeling of the World Agroforestry Centre in Nairobi, Kenya; José de Jesús Luna Ruiz of the Universidad Autónoma de Aguascalientes in Aguascalientes, Mex.; and Geo Coppens d’Eeckenbrugge of the Centre National de la Recherche Scientifique in Montpellier, France.

The study’s funding came from the Fulbright Program, the University of California’s Institute for Mexico and the United States and UC Davis’ Department of Plant Sciences.