New soybean variety with CystX offers protection from all nematode races.

Growers plagued by soybean cyst nematode (SCN) troubles should look at a new line of SCN-resistant soybeans. The line will be available in limited supply for purchase this fall. Purdue University and Midland Genetics Group research shows the variety is resistant to SCN. No cysts have developed on the roots of the new line.

The SCN-resistant characteristic is offered in a conventional Midland variety for the 2001 crop. Clyde Sylvester, member/owner of Midland, says Roundup Ready varieties should be available in 2002.

Midland's six member companies will be the first to offer a soybean variety bearing the SCN-resistant technology called CystX. The CystX technology was developed at Purdue University and is available for license to seed companies to cross with elite soybean varieties. It is not a genetically modified organism.

Good yielder. Soybean varieties with the CystX technology perform well. "It has very good yield potential," reports Purdue researcher Rick Veirling. "Our data show no yield loss or yield cost with the resistance. Plus, it is a far better resistance than what farmers are currently being sold."

Veirling anticipates that many varieties in the future will contain the CystX resistance. "I don't think the seed supply will be enormous this fall," he adds. "But in the future, it will be widely available. It will be out in test plots this summer."

SCN has spread widely throughout the Midwest. Researchers report that about 40% of Indiana soybean fields are infested with the nematodes. They estimate that infestation rates run higher in Illinois at 80% and in Iowa at 70%.

Typical treatment for yield-robbing nematodes includes crop rotation and use of the varieties exhibiting some SCN-resistance. But most resistant varieties still exhibit cysts on the roots.

"CystX is extremely important because of its complete resistance and high yield potential," Veirling says. "You can use it and be relatively sure you will get SCN resistance."

Research payoff. The CystX technology represents the culmination of many years of intense research. The Purdue team developing it included Veirling, Jamal Faghihi, Virginia Ferris and the late John Ferris.

During the lengthy research, partially funded by the Indiana Soybean Board, the Purdue team screened 7,000 individual plants, seeking the genetic event that combined high yield and complete resistance. The single event discovered has become CystX.

The researchers used the Hartwig source of SCN resistance in CystX. Hartwig has been identified as a source of resistance but was not widely used because it did not produce good yields. The Purdue researchers were able to move the genes for SCN resistance into high-yielding genetic plants. A new genetic-event detection method made it possible for the researchers to accomplish this. Before, Faghihi says, looking for the genetic event was like looking for a needle in a haystack.

"We used some alternative methods that are unique to our group," Veirling explains. "It is not quite a traditional breeding system, but a combination of genetic experiments and plant breeding."

Once the event was identified, the researchers were able to quickly make the material available to plant breeders.

Work doesn't end. Today, the Purdue researchers are looking at other sources of SCN resistance. "This is not the end of SCN, of course," Veirling reports.

So the researchers are seeking other sources of resistance to broaden the SCN resistance sources available to growers.

For more information about CystX, contact Midland Genetics Group, Dept. FIN, 1906 Kingman Rd., Ottawa, KS 66067, 785/242-3598, e-mail midland@kanza.net.