David Bedford bites into 500 to 600 apples every day. His job during apple season is to test the flavor and texture of new varieties, and make life-or-death decisions on whether the five-year-old trees that produced them will be cut down or spared to grow for another year.

"If all I can say about an apple is that it's not bad, it gets thrown out," he said. "It's got to be more than fine. It's got to be 'wow.'"

For the past 32 years Bedford has worked as an apple breeding specialist at the University of Minnesota's Horticultural Research Center, located just west of the U's arboretum in Chanhassen. From mid-August to mid-October, he patrols long lanes of apple trees that have been crossbred to produce varieties that may become the next national or even international bestseller.

Only one apple variety out of 10,000 will be good enough to be released to the public, and the process takes 20 to 30 years.

"My job is like being marooned on a desert island, and walking up and down the beach for 20 years looking for a few diamonds," Bedford said.

Four varieties developed at the center have been released in recent years, including Honeycrisp, an international blockbuster (1991), Zestar! (1998), SnowSweet (2006) and SweeTango (2009). The center also has extensive programs that have bred Minnesota-hardy grapes, strawberries, blueberries, raspberries and other fruits. The apple program is one of only three in the nation, along with research at Cornell University in New York and Washington State University.

Scanning the orchard

Last week Bedford strode past 10,000 young apple trees to see which are starting to bear fruit, and whether the fruit has matured to peak flavor to be tasted. They're closely spaced, about 2 feet apart, in 600-foot rows, tethered to strands of wires. He scanned branches loaded with color, from lemon-yellow early apples to all shapes and sizes of greener fruit tinged with pinks or blushed with reds.

Each tree is unique, he said, the product of a process where apple blossoms were finger-touched with pollen to crossbreed different varieties, then grown in a bag at the end of a branch, and finally harvested for seeds that sprouted and grew into seedlings in greenhouses.

What emerges are about 2,500 new seedlings that are started outdoors each year, and Bedford must throw away an equal number of five-year-old trees to keep pace. "It's like skiing in front of an avalanche," he said. "You just can't afford to fall down."

Bedford passed several trees where the apples were still too green, and said he'd check them again each succeeding week until they were ready.

He spotted a tree where apples looked mature. He picked one, bit into it, and said it tasted ripe. He then cut the apple in half and sprayed it with an iodine solution that reacts with starch. If the flesh turns all black, the apple is immature; if it remains all white, the apple has too much sugar and is overripe.

In this case, the apple was partly dark, showing that it had the right balance to be evaluated.

Bedford took another ripe apple from the same tree, bit into it, and said the flavor was too astringent.

"When it fails the mouth test, it's the end of the game," he said.

He marked the tree with orange paint for removal.

Blue ribbon trees

Only 10 to 15 trees out of 2,000 to 3,000 each year will get what Bedford calls "blue ribbon" status. Those tasty survivors will be assigned a number, and four clones will be planted and raised in an area with more space.

"We need to see them in cold winters and hot summers," he said.

Bedford will observe and taste the blue ribbon apples for the next 10 to 15 years, keeping field notes each fall that also include how volunteer panels rank the apples in blind taste tests.

The biggest winner has been Honeycrisp, said Peter Moe, operations director at the nearby University of Minnesota Landscape Arboretum.

"The texture is so fabulous," he said. "You bite into it and a big chunk breaks off."

More than 12 million Honeycrisp trees have been planted in several U.S. states and around the world, Moe said, including New Zealand, Chile and Africa.

Old favorites

Generating income was not the goal when the U purchased the research property and began to grow apples there in 1907. For the next half-century, Moe said the main goal was to develop cold-hardy varieties that could survive Minnesota's extreme temperatures.

About 80 percent of the apple varieties now grown commercially in the state were developed at the center, he said, including the early-season Beacon and State Fair, mid-season Red Baron and Sweet Sixteen, and late-season Honeygold, Haralson and Fireside apples.

Having several varieties isn't good enough, said Paul Hugunin, because consumer tastes change and competition to develop "the next great apple variety, the next flavor, the next new thing" is fierce in the worldwide apple industry.

Hugunin, who works for the Minnesota Grown program in the state Department of Agriculture, said continued research is critical at the U, even though it has already produced "a very nice portfolio of harvest dates, flavors and uses for apples just within the Minnesota-developed varieties."

Bedford said that the painstaking work of crossbreeding apples, raising seedlings and throwing away more than 99 percent of them may change in the future if scientists begin to use genetic engineering to create new varieties. That's not likely in the short term, he said, because many consumers refuse to buy any genetically modified food, especially in Europe.

Even if it took 31 years to develop the Honeycrisp, Bedford said, the final product was worth it. "You bite into that apple and it cracks and the juice kind of runs down in your mouth and, wow, that's like a new sensation," he said. "To have that crisp texture is really the highest compliment."

Tom Meersman • 612-673-7388