Extension Ag Update
May/June 2001
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Research Results

New Insect-Resistant Corn Germplasm Line

Agricultural Research Service scientists recently released a new corn germplasm line that will be a source for developing corn plants resistant to the southwestern corn borer, Diatraea grandiosella, and the fall armyworm, Spodoptera frugiperda. Plant geneticist William P. Williams and others have developed the corn germplasm line, Mp716, that is resistant to leaf feeding by these formidable pests. The new line was developed by self- pollinating a cross between two other germplasm lines for eight generations and then selecting for the desired traits. The milky-white larva of the southwestern corn borer appears in early June. After feeding on the whorl, tightly coiled leaves within the stalk of the corn plant, it moves down the stalk and begins to tunnel within. If the larva feeds on the bud of the plant within the whorl, the plant's entire yield is lost. Female southwestern corn borers can lay from 300 to 400 eggs in their lifetime. The fall armyworm attacks corn and a variety of other crops including tomato, cotton and alfalfa. Like the southwestern corn borer, this pest also damages the whorl of the plant. This feeding produces frayed holes in the leaves that become apparent when they are unfurled. In addition, the larvae of the fall armyworm also feed on immature ears and tassels. The new germplasm line was evaluated for three years by infesting plants in the whorl stage of growth with 30 young larvae and checking for damage 14 days later. Mp716 was found to be only moderately damaged by these insects.

More Efficient Ethanol Production Closer to Reality

Producing fuel ethanol from grains at low temperatures may be more feasible, thanks to improved enzymes developed in the laboratory. When grains are processed into ethanol, starch granules are cooked at 105 degrees Celsius (about 223 degrees Fahrenheit) to convert the starch to a form that enzymes can degrade into simple sugars. About 10 to 15 percent of the processing energy required to make ethanol goes towards providing the heat used to cook the starch. Producers, of course, aim to use as little energy as possible to make the fuel. Researchers at ARS Western Regional Research Center in Albany, Calif., have developed variants of a natural starch-degrading enzyme that breaks down starch 50 times faster than the original enzyme in the laboratory, at 37 degrees Celsius (about 99 degrees Fahrenheit). Enzymes with greater activity at low temperatures could facilitate development of more energy-efficient methods of ethanol production. These findings could also provide additional outlets for wheat, barley and other grains, and support efforts to increase nonfood uses of agricultural products.