Trait by trait, plant scientists swiftly weed out bad seeds through marker-assisted breeding

When his tomato plants were just a week old, technicians manually punched a hole in each seedling to get leaf tissue that was taken to a nearby lab, converted into a chemical soup and then scanned for genetic markers linked to desired traits.

Krivanek uses the information to keep just 3percent of the seedlings and grow them until they fruit this spring, when he can evaluate fully grown plants, keep a few hundred, sow their seeds and then screen those plants.

Im improving my odds. Maybe I can introduce to market a real super-hybrid in five years, Krivanek said. A predecessor might take a whole career.

The technology called marker-assisted or molecular breeding is far removed from the better-known and more controversial field of genetic engineering, in which a plant or animal can receive genes from a different organism.

Marker-assisted breeding, by contrast, lays bare the inherent genetic potential of an individual plant to allow breeders to find the most promising seedling among thousands for further breeding. Because the plants natural genetic boundaries are not crossed, the resulting commercial hybrid is spared the regulatory gantlet and the public opposition focused on such plants as genetically modified Roundup Ready corn or soybeans, which are engineered to withstand herbicide sprays.

Marker-assisted breeding has been embraced not only by the multinational biotech companies here in Californias Central Valley but also by plant scientists in government, research universities and nongovernmental organizations fervently seeking new, overachieving crops. The goal is to sustainably feed an expanding global population while dealing with the extremes of climate change.

But critics of Big Agriculture worry about the needs of small-scale farmers and breeders. Low-tech conventional breeding judging plants by how they look and perform, not by their DNA has been the lifeblood of small seed companies and local growers, often in conjunction with breeding programs at land-grant universities. But those programs have shrunk by a third in recent years, and the remaining ones are increasingly gravitating to the trendy sphere of molecular breeding.

Organic farmers, who need crop varieties designed for specific regions and less-intensive growing methods, are not being served by the new applied science, said John Navazio, a senior scientist with the Organic Seed Alliance.

There used to be a significant winter spinach production area in southern Virginia and Delmarva, and thats completely gone, he said. The spinach-growing industry has moved to megagrowers in California and Arizona.

Progress comes sooner

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Trait by trait, plant scientists swiftly weed out bad seeds through marker-assisted breeding