Pinto Beans ... Just Right

Research leads to new disease-resistant varieties

Bean processors are picky people. Ask the farmers who manage Colorado's 150, 000 acres of dry beans. To be successful in the market, a bean must be the right color, the right size, the right shape. Not too big. Not too small. Not too round. Not too flat. Each bean must be, as Goldilocks would say, "Just right."

So for plant breeder Mark Brick, whose number one goal is to provide farmers with high-yielding, disease- resistant, excellent bean varieties with good seed quality and profit-making potential, he also must ensure that any new variety will pass muster with bean processors and educated consumers. Take pinto beans, which make up about 95 percent of Colorado's dry bean crops. They have to have a bright cream background color with distinctive cocoa-colored markings. Informed consumers won't accept beans that appear dirty brown.

Since becoming Colorado State's dry bean breeder in 1986, Brick has been working to develop pinto bean varieties that will resist rust, root rot, blights, and other prevalent diseases. Pinto plants grow as a mass of vines that retain humidity and create an inviting environment for disease, so Brick also is breeding for upright architecture, which is easier to cultivate, irrigate, and harvest. "If you have upright plants in rows, and the space between the rows is open," Brick explains,"the plants stay dry and aren't conducive to disease."

In 1994, Brick released Arapahoe, a pinto bean variety that resists white mold and grows semi-upright. Now he's breeding for resistance to rust, which occurs in Colorado every year. "Some years rust is all over, damaging 30 to 40 percent of the crops," Brick says. "In an average year, it might cause a loss of 5 to 8 percent, and it can be devastating to producers who do not apply fungicides to control the disease."

Developing a new variety and making it widely available takes a decade or longer. In the first year, Brick may cross one parent, which resists rust, with another parent that has good qualities except for its susceptibility to rust. The offspring will contain traits from both parents. He then selects progeny for both rust resistance and the good traits needed for a new variety. Year after year, Brick chooses the best plants from each new generation to produce more of the desired traits. It may be five to seven years before he gets what he's looking for. Then he tests the plants at locations throughout Colorado and the United States.

Brick's network of colleagues include plant breeders like himself in North Dakota, Idaho, Michigan, Nebraska, Washington, and other parts of Colorado. "My colleagues test these plants in environments other than Colorado, so I can see whether they're going to make it in the real world," says Brick. "The plants have to perform well in a broad range of environments. North Dakota offers a different spectrum of diseases than Colorado, and Idaho is a different environment altogether – no bacterial diseases but serious viral diseases. In eastern Colorado, I see heat stress, common blight, white mold, and rust. Only by testing the new lines in all these environments do I get to see what these plants are made of."

When he finds a plant that grows well at most or all of the sites, he tests the variety again through cooperating nurseries located throughout the U. S. and Canada. "Now I'm looking at seed quality, disease resistance, all sorts of things." When the variety meets the criteria, he releases it. The plants go to Fruita, Colo., where the line is increased for certified seed production. Fruita, like most regions on the Western Slope, does not have common bacterial diseases, says Brick, which is the reason that the certified bean seed industry is there.

Brick attributes the success of Colorado State's plant breeding program to its numerous partners – research associate Barry Ogg, plant pathologist Howard Schwartz, extension crop testing specialist Jerry Johnson, foundation seed manager Fred Judson, and extension agents, research associates, and nurseries across the state and country. "If you didn't have all these resources, you couldn't be successful," says Brick. "It's a real team approach to developing a new bean variety that farmers can profit from."