Serogroups of Rhizobium japonicum in Soybean Nodules Sampled in Iowa1
- G. E. Ham,
- L. R. Frederick and
- I. C. Anderson2
Serogroups of Rhizobium japonicum present in the nodules of soybeans and their relationship to soil properties were studied on 613 nodule samples obtained at 75 locations during 1965 and 1966. The homogenized nodule suspensions were typed serologically by a quick agglutination test using somatic antisera of cultures of R. japonicure representing seven serogroups. Only 2.8% and 1.1% of the nodules tested failed to react with one of the seven antisera in 1965 and 1966, respectively.
R. japonicum serogroup 123 was the dominant serogroup found in soybean nodules on soils below pH 7.5, while serogroup 135 dominated when the soil pH was greater than 7.8. Individual serogroups were related to at least 2 and as many as 6 soil properties. In 1966, 81% of the variation in the occurrence of serogroup 135 was attributed to soil pH. Relating the occurrence of serogroup 135 to all soil properties accounted for 84% of the variation or only 3% more than pH alone. Less of the variation in other serogroups was attributed to soil properties.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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