Synopsis Strains of Rhizobium japonicum applied as inoculum at different rates and by different methods differed greatly in the proportion of nodules produced on soybeans (Glycine max (L.) Merr.) grown in soils containing effective soybean rhizobia. The percentage of nodules produced by all strains applied at the standard rate of inoculation was low and averaged 5%. Increasing the amount of inoculum applied increased the percentage of nodules produced by some strains but had little effect on others.

Synopsis Groupings of isolates indicated a different population of bacteria in the nodules of plants grown in different soils. In 5 of 6 soils, 49 to 82% of the isolates were of 1 or 2 predominant groups with the predominant groups differing among soils. Populations of bacteria in nodules of greenhouse and field plants grown in a given soil were essentially the same.

MIEANS, IRA M. (U.S. Departimieiit of Agiiculture, Beltsville, Md.), HERBERT W. JOHNSON, AND R. A. DATE. Quick serological method of classifving strains of Rhizobiwni japonicmnot in nodules. J.

Synopsis Interactions were indicated by the chlorosis response of 116 soybean varieties to selected bacterial strains and by a selected group of varieties to 70 bacterial strains. The response of each of 11 varieties to 8 strains was different from that of any other variety. No two of the 8 strains resulted in the same response of all 11 varieties.