Monsanto To Introduce Aphid-Tolerant Soybean Varieties

Monsanto Co. will introduce new Genuity Roundup Ready 2 Yield soybean varieties with aphid tolerance in 2011 designed to help protect soybean yields from these damaging pests.

Since their identification in 2000, soybean aphids have become a major pest in soybean fields throughout the Northern United States. When left untreated, these insects can multiply rapidly and cause significant yield losses. They feed on the sap of the soybeans, leaving behind stunted, curled soybean plants which lead to reduced pod set and seed size. Feeding also potentially transmits harmful viral diseases.

“Monsanto’s new aphid-tolerant soybeans will be introduced initially in maturity groups I and II in the upper Midwest, the areas where aphid populations are typically the highest,” says Aaron Robinson, Monsanto soybean traits technical manager.

Aphid tolerance is conferred by the native Rag1 gene, which was discovered by soybean plant breeders at the University of Illinois. The new Genuity Roundup Ready 2 Yield aphid tolerant varieties will be available with Acceleron insecticide/fungicide seed treatment products, which provide protection against early-season diseases and insects, including soybean aphids, adding an additional layer of protection for more complete aphid control.

“Research trials have shown that these aphid tolerant varieties treated with Acceleron seed treatment products delayed aphid population development by two weeks in environments with high aphid populations,” Robinson says.

In environments with medium aphid populations, he said the economic threshold of 250 aphids per plant was never reached and therefore no foliar insecticide was applied to the Genuity Roundup Ready 2 Yield Aphid Tolerant varieties. However, the non-aphid tolerant soybean varieties did require a foliar insecticide application.

Shawn Conley, state soybean specialist at the University of Wisconsin, says aphid-tolerant technology would offer multiple benefits.

“If you look at the impact that these insects have, true aphid resistance could provide a real economic boon to farmers in helping to reduce their yield loss,” he says. “Another advantage is that this technology could help eliminate some of the early insecticide sprays that also reduce the population of beneficial insects.”

“Genuity Roundup Ready 2 Yield aphid tolerant varieties provide a more flexible insecticide application window or, in some cases, eliminate the need for foliar insecticide treatment, providing a potential savings to the grower of $9 to $14 per acre,” Robinson adds. “Use of these aphid tolerant varieties, timely scouting and foliar insecticide application, if necessary, are all part of an effective integrated approach to managing soybean aphids.”

The aphid tolerance gene will only be introduced in combination with Monsanto’s Genuity Roundup Ready 2 Yield trait to help maximize soybean growers’ yields. More soybean varieties in additional maturity groups will be available in with the Genuity Roundup Ready 2 Yield trait in subsequent years.

(Source: Monsanto news release)

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