Development of resistance to caterpillars in soybean

Summary

The development of high-yielding soybean cultivars with broad spectrum insect resistance is the overall goal of this project, as a component of the soybean improvement strategy at UGA. Soybean yield loss to insects and diseases is higher in the Southeast due to the favorable climate. Unlike other regions that have a few key pests, soybean in Georgia can be infested by over 20 unrelated insects.

Situation

Insecticides are used to control insect outbreaks in soybean, leading to increased costs of production and concerns about pesticide residues in the environment. However, the most economical and sustainable method to control insects is to breed crops that contain insect resistance genes, and thus avoid or reduce the need for applications of insecticides.

Response

Given that sustainable resistance needs additional resistance genes to be deployed with time, and recognizing the long lead time needed to find, characterize and use new genes, the search for new resistance genes is an ongoing process. New soybean lines are continuously being screened for resistance, checking for the presence of known genes and using mapping to detect the presence of new genes in newly discovered resistant lines.

Impact

Additional caterpillar-resistant soybean lines are now available for use in private and public breeding programs. Each line contains one or more of the four genes for resistance that have been discovered and characterized to date. These can be combined with each other in breeding programs to broaden the types of caterpillars controlled and the durability of resistance. The best of the resistance genes have been combined with each other and are being moved into commercial varieties. And, another caterpillar-resistant soybean has been discovered, and it currently being characterized to discover additional genes for resistance. There is now a better understanding as well of how insect resistance works in soybean. The main way caterpillar resistance is achieved is by partly blocking isoflavone production, which permits condensed tannins to accumulate in leaves. This information should be useful for the smart design of additional insect control strategies. Whereas most of the work has been done to achieve resistance to the main caterpillars that attack soybean, additional work was also done to find resistance to the Japanese kudzu bug, which became a major problem in Georgia in the years following the introduction of kudzu bug into the state. Two wild soybean plants were discovered that deter feeding by kudzu bugs. This work is on hold, since kudzu bugs have not been problematic the past couple of years. However, the work is ready to continue should kudzu bugs ever again become problematic.

State Issue

Agricultural Profitability and Sustainability

Details

• Year: 2016
• Geographic Scope: National
• County: Clarke
• Program Areas:
  • Agriculture & Natural Resources