ALBUQUERQUE — Think the bold, sweet scent of roasting green chile is one of the best smells around? Well it's about to smell even better — and taste better, too.

Researchers with New Mexico State University's Chile Pepper Institute in Las Cruces have developed two new chile varieties with improved flavor and aroma after essentially "cleaning up" two existing varieties popular with farmers and chile aficionados.

The new varieties — known as NuMex Heritage Big Jim and NuMex Heritage 6-4 — have five times the flavor and aroma of the varieties they were created from — the NuMex Big Jim and New Mexico 6-4.

Paul Bosland, professor of horticulture and director of the Chile Pepper Institute, said researchers created the new varieties because the old Jim Big and 6-4 varieties had "run out," losing their signature flavor after many growing seasons.

"Over the years, they lost their identity. They're not true to type anymore. The chile the farmers were growing had a great look and disease resistance, but no taste," Bosland said. "In New Mexico, you have to have chile that tastes good."

Call off the psychologists and bring in the chile experts.

Chile can lose its identity after cross-pollination with other varieties, Bosland said.

"As the bee in the garden or field dotes from one plant to another, it could possibly bring pollen from a different plant in. Or in your mechanical mix with seeds, you make a mistake. There are always accidents that occur along the way," he said.

And the varieties have had a long time to get mixed up.

New Mexico 6-4 was created in 1957 by Roy Harper. It was a less-hot version of a variety called New Mexico No. 6. The variety is popular with green chile processors.

The NuMex Big Jim, released by Roy Nakayama in 1975, produces mild to hot, long, thick, smooth, fleshy peppers, often used for dishes such as chile rellenos. It is also listed in the Guinness Book of World of Records as the world's largest chile.

Bosland and his colleagues at the institute decided to get the varieties back to their old selves, so to speak.

In 2002, they obtained the original seed of both varieties, frozen in liquid nitrogen, from the USDA's National Seed Storage Lab in Fort Collins, Colo. From there, the researchers worked to create breeding lines for new varieties that would capture the original flavor of the chilies while making improvements to help farmers stay competitive.

"Now, both varieties have much more flavor compounds, better yield and better plant habits. With these new guys, when you roast them the smell is much stronger and the chile flavor is so much more intense. My mouth is watering just talking about them," said Danise Coon, the Chile Institute's program coordinator.

Coon said characteristics of the new varieties include high yield, uniform heat level, easy de-stemming and traditional flavor.

The researchers also used mass-spectrometry laboratory testing, which detects flavor compounds, to determine if they hit the mark for improved flavor.

But they needed proof outside of the lab to truly test their work.

The research team had members of the New Mexico Chile Commission visit the fields for a taste test, Bosland said.

"We had them tasting (the chile from) every plant, and we flagged the ones where they said, 'This has the flavor and taste we remember.' And then we took the chile out and put it on green chile cheeseburgers, and people told us it was the best-tasting chile they'd ever had."

Bosland said the team discovered that people were trying to steal the chile from test fields near the university.

"They're so good people are stealing them. We're pretty excited," Bosland said with a chuckle.

The chile was grown by Biad Chili Ltd. Co. in Mesilla Park, where it was guarded and seeds were collected.

Chris Biad, a partner in the company, said seeds for the NuMex Heritage 6-4 are available in large quantities from the company at $15 a pound. Seeds for the NuMex Heritage Big Jim will be available from Biad at the end of 2009. Gardeners can purchase small pouches of seeds through the Chile Institute.

"This is the pure source of this variety, as pure as you can get," Biad said.

For the future, Bosland and his team are looking at improving the Sandia variety from original seed for release in about two years.

With their new identity intact, Bosland said the heritage varieties can help New Mexico's chile industry continue to tout its quality.

"The chile and that flavor is our connection to the earth. Having good-tasting food is very important, and consumers are moving back toward more flavorful food," Bosland said.