The southern root-knot nematode (Meloidogyne incognita) is the most important yield-limiting plant-pathogenic nematode that affects soybean production in the mid-South. It is found in nearly all soybean producing counties in Arkansas and can cause significant (>50%) yield loss when the wrong soybean variety (i.e. susceptible) is planted in field with a high population density of root-knot nematodes.
During the 2017 season the Lonoke Plant Pathology Program selected 48 soybean varieties that were grouped based on herbicide technologies and maturity groups to be evaluated in a root-knot nematode infested field. The final nematode population densities (Pf) ranged from 800-1300 individuals per 100 cm3 soil in each test.
Percent of root system galled was estimated for at least 10 root systems from each replication per test at R4-R5 growth stage. Soybean varieties in each category with the lowest gall rating contributed to the greatest yield (Table 1-4).
Soybean varieties with <10% of root of system galled are considered resistant compared to those with the greatest galling percentage. For example, ‘Go Soy 49G16’ is resistant compared to ‘Asgrow 4632’ (5.4/78.3 = 6.9%).
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This information and that on the variety testing website can be used to make decisions about variety selection for the 2018 cropping season.
View the pdf version for data tables and information: 2017 Selected Soybean Reaction to RKN data
The authors would like to thank the Arkansas soybean promotion board for supporting this project, various seed companies for donating seed and our cooperators at Fletcher Farms for plot space on their farm. If you have questions, please contact Travis Faske at firstname.lastname@example.org