A relative of Swiss chard, the versatile sugar beet does more than serve as a reliable source of high-quality sugar to sweeten foods we eat. It provides a nutritious addition to feed for beef and dairy cattle as well as sheep. Its leafy greens are a favorite with some home gardeners. Sugar beet molasses, a processing byproduct, is used for making yeast, chemicals, and pharmaceuticals. Growers in 14 states produce America's sugar beet harvest, worth more than $1 billion annually. 
Sugar beet growers helped fund Yu's research. In those tests, he showed that his experimental M6-1 sugar beets, when exposed to very high numbers of nematodes in the greenhouse, suffered little if any damage. The six different species of root-knot, or Meloidogyne, nematodes that Yu used in his studies are heavy hitters. They make up 98 percent of root-knot nematodes in the world's agricultural soils. Yu's discovery is a first: So far, no other researcher has reported any sugar beets-or any crop species, for that matter-that resist all six species. 
In addition to nematode enemies, sugar beets can also fall victim to diseases like rhizomania, or crazy root, called that because of the odd-looking roots of diseased plants; Erwinia root rot, caused by a bacterium; and virus yellows, named for the sickly color of leaves of afflicted plants. Plant geneticist Robert T. Lewellen at Salinas has bred lines of hardy sugar beets that are resistant to these and other major diseases of sugar beets grown in the western United States. Some of the new sugar beets have multiple resistance. That means they can withstand attack by a combination of these microbial villains. Lewellen is also working with ARS plant pathologist John J. Weiland from Fargo, North Dakota, and others at Salinas to find marker genes for natural resistance to powdery mildew. When uncontrolled, this fungal opponent can reduce yields by up to 30 percent. Somewhat like molecular signposts, markers may indicate the presence of genes that confer valuable traits(in this case, disease resistance). Finding those genes, says Weiland, will speed development of sugar beets that can shrug off attack by their worst enemies. In fact, molecular biologists could rebuild these naturally occurring genes, then slip them back into plants to "bulletproof" tomorrow's sugar beets. The work should help reduce growers' reliance on fungicides and other farm chemicals. Meanwhile, scientists in the ARS Sugar Beet Research Unit at Fort Collins, Colorado, have produced dozens of breeding lines with varying levels of resistance to three other serious diseases: curly top virus, spread by insects known as leafhoppers; Rhizoctonia root rot, a soilborne fungal disease; and Cercospora leaf spot, another fungus. "We've made a good deal of progress," says ARS geneticist Leonard W. Panella. "We have lines that look good in a severe, artificially induced field epidemic. They're not fully immune, of course, but they're highly tolerant." Panella's team now aims to combine resistance to multiple diseases. T