Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Discovering soybean plants resistant to aphids and a new aphid

12.08.2009
This year farmers in the Midwest are growing a new variety of soybeans developed by University of Illinois researchers that has resistance to soybean aphids. However, in addition to the resistant plants, U of I researchers also discovered a new soybean aphid which is not controlled by this resistance.

Soybean aphids made their first appearance in North America in the summer of 2000, resulting in tremendous crop losses for farmers. U of I researchers began immediately searching for a variety of soybean that is resistant to the new pest.

Dowling and Jackson were the first two resistant varieties to be identified. "We have the U. S. Soybean Germplasm collection here at Illinois. It houses about 18,000 different accessions," said Glen Hartman, soybean plant pathologist with the USDA and U of I. "We didn't screen all 18,000, but we went through a small set of 4,000 to 5,000 and that's where Jackson and Dowling came from. We knew they were resistant, but we had to do the crossings and look at the inheritance patterns to figure out whether the resistance was because of a single gene or multiple genes."

With additional screening, a third soybean resistant to aphids was found -- a Japanese variety known as PI 200538. "After we mapped the genes from these sources, we discovered that Jackson and Dowling had genes mapping to the same place on a chromosome and the PI had a gene mapping to a different place. This means that Jackson and Dowling likely have the same resistance gene and PI 200538 has a different gene we can use in breeding."

Diers said that both Jackson and Dowling originated in the southern United States, so neither could be grown to seed in the Midwest. They used traditional breeding techniques together with marker-assisted selection to quickly breed the resistance genes into varieties that are adapted to the Midwest.

"Because the aphid resistance is conferred by a single gene in the resistance sources, we were able to breed these genes into Midwest-adapted varieties quickly and easily," Diers said. "We can complete three crossing generations a year by using both greenhouses and fields. This year is a milestone because we now have a variety that's being commercially produced that carries the resistance gene from Dowling. This is its first commercial production of an aphid-resistant variety in the Midwest."

Unfortunately, the celebration didn't last long. While studying soybean plants, they discovered a new type of aphid. "We were excited about finding the resistance. We discovered this gene from Dowling and Jackson, bred it into varieties and we 'hoped that we could solve the aphid problem,' but of course things are never that simple," Diers said. "We found that there are different biotypes of soybean aphids, including a biotype that can overcome the resistance gene for Dowling."

In tests, this new aphid was able to infest Dowling as well as it could any susceptible genotype of soybean. "We don't know how widespread those aphids are or whether or not this is actually going to occur in fields, but certainly it's something to be concerned about because we know that resistance isn't going to be perfect," Diers said.

The good news is that the PI 200538 gene for resistance is different than the one in Dowling and Jackson. "We found that this second resistance gene in the PI protects the plants against this new biotype of aphid. We are currently breeding the PI 200538 gene into varieties, but it will be at least a few years before any varieties with this gene will be released."

Even after the appearance of this new aphid, Diers is still optimistic. "We have one variety with the Dowling resistance gene that's being commercialized this year. A company is increasing seed of a second variety with the Dowling gene that should be commercialized next year. So we'll have two varieties available to growers." He explained that the U of I aphid-resistant germplasm and marker technology is licensed to private seed companies who are using it to breed their own varieties."

The first aphid-resistant variety developed and released by the University of Illinois is Round-up Ready, and the second is a conventional, non-Round-up Ready variety. Diers says "we believe that the aphid resistance in a conventional background will be especially helpful to organic soybean producers because currently if they have aphids in their fields, they don't have any practical method of control because they cannot spray insecticides. I've been contacted by some organic growers in northern Iowa and southern Minnesota who are ready to give up growing organic soybeans because aphids have caused such large losses."

Diers said that resistant varieties can save farmers money and help the environment. "Farmers have been controlling soybean aphids by spraying insecticides. If we can deploy resistance, this could reduce the use of these insecticides, which will have many environmental benefits."

The message to farmers is that there are going to be varieties with soybean aphid resistance available. "The tests we've done have shown that we have less aphid reproduction on these resistant lines than on susceptible lines," Diers said. "But so far the resistance isn't a magic bullet. You can't grow these aphid-resistant varieties and not scout for aphids because there may be aphids in your fields that can defeat the resistance."

The other unknown is how adaptable aphids will be to these new varieties. "Our hope is that we can combine these two genes and get more durable resistance," Diers said. "We hope that we can develop a plant with a number of resistance genes so that if any one of them breaks down, the plant would still be resistant."

This work was supported by funding from the United Soybean Board and the Illinois Soybean Association. "Without funding from these organizations, our research on aphid resistance and the development of aphid-resistant varieties would not have been possible," says Diers.

The work appeared in the following journals: Soybean Aphid Resistance Genes in the Soybean Cultivars Dowling and Jackson Map to Linkage Group M was published in a 2007 issue of Mol Breeding. Discovery of Soybean Aphid Biotypes was published in the May-June 2008 issue of Crop Science. Inheritance of Resistance to the Soybean Aphid in Soybean PI 200538 was published in the July-August 2009 issue of Crop Science. Funding was provided by the United Soybean Board and the Illinois Soybean Association. Yan Li, Curtis B. Hill, Shawn R. Carlson, Ki-Seung Kim, M.A. Rouf Mian, and Laura Crull contributed to the research.

Debra Levey Larson | EurekAlert!
Further information:
http://www.illinois.edu

More articles from Agricultural and Forestry Science:

nachricht New data unearths pesticide peril in beehives
21.04.2017 | Cornell University

nachricht New rice fights off drought
04.04.2017 | RIKEN

All articles from Agricultural and Forestry Science >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

Im Focus: Quantum-physical Model System

Computer-assisted methods aid Heidelberg physicists in reproducing experiment with ultracold atoms

Two researchers at Heidelberg University have developed a model system that enables a better understanding of the processes in a quantum-physical experiment...

Im Focus: Glacier bacteria’s contribution to carbon cycling

Glaciers might seem rather inhospitable environments. However, they are home to a diverse and vibrant microbial community. It’s becoming increasingly clear that they play a bigger role in the carbon cycle than previously thought.

A new study, now published in the journal Nature Geoscience, shows how microbial communities in melting glaciers contribute to the Earth’s carbon cycle, a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

7th International Conference on Crystalline Silicon Photovoltaics in Freiburg on April 3-5, 2017

03.04.2017 | Event News

 
Latest News

New quantum liquid crystals may play role in future of computers

21.04.2017 | Physics and Astronomy

A promising target for kidney fibrosis

21.04.2017 | Health and Medicine

Light rays from a supernova bent by the curvature of space-time around a galaxy

21.04.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>