Plant Nematology Laboratory
573-884-9118

Soybean cyst nematode HG type "race" test

The HG type "race" test takes place in a greenhouse, where replications of the seven indicator lines (with the seven sources of resistance) are each inoculated with 1,000 eggs extracted from your soil sample and grown for 30 days under optimal conditions. Then the females are carefully removed, counted, and the percentages calculated. At least 40,000 eggs are needed for this test, so a sample containing at least a gallon of soil is required.

The HG type test (Heterodera glycines) is an expansion of the old race test that used four different sources of resistance. The new test includes seven sources of resistance and the results are shown as a percentage, indicating how much the nematode population from your sample increased on each of the seven lines. The percentage is based on the number of females (cysts) on the susceptible bean, Lee 74. This test will tell you which sources of resistance would be good for your field and which would be poor. The University of Illinois Extension Web site has a comprehensive listing of the sources of resistance for commercial soybean lines.

Who should have an HG type "race" test run?

If you have been growing SCN-resistant soybeans for years, a test may provide useful management information. First, you should always have an SCN egg count run, even though you may not see any symptoms showing in the field. If it is greater than 10,000 eggs/cup, a test would be helpful. Remember, just because you grow soybeans resistant to SCN, your “source of resistance” may not be appropriate for your field. The test will tell you the best sources of resistance for the population of cyst nematodes in your field.

What does Missouri’s HG type "race" test include?

The Plant Nematology Lab at the University of Missouri includes both the new HG type designation and the old race test designation in the test results that are returned, along with an explanation of how to use the information. As a bonus, you can also submit up to two of your favorite soybean varieties to test along with the seven HG indicator lines, if you wish. Please include at least 15 seeds of each line when you send the soil sample, if you want this option. This will tell you how the SCN population in your sample reproduces or builds up on the soybean varieties you submitted.

Cost

$50 per sample, Missouri
$100 per sample, out of state

Updated 11/30/07