Studies of Bacillus Radicicola of Canada Field Pea 



61 



resulted from contamination, or from a few surviving organisms not de- 

 tected by the plating can only be conjectured. The remaining cultures 

 all produced good inoculation, with the exception of the sawdust and 

 the lactose culture, the average number of nodules per plant varying 

 between 3.7 and 15.8. To what extent this variation in the number 

 of nodules is due to the infecting power of the different cultures 

 it is difficult to say with certainty; but that a part of the variation 

 is due to other causes is evident from the data in the next to the last 

 column in table 12. In this column the figures represent the average 

 number of nodules per plant for every flowerpot. Since three flowerpots 

 were inoculated with each culture, the extent of variation in the number of 

 nodules in these pots must be due to other causes than the infecting 

 power. A number of the more pronounced cases of variation in the 

 number of nodules in the three respective flowerpots which were inoculated 

 by the same culture are shown in table 14: 



TABLE 14. Variation in Average Number of Nodules in Some of the Flowerpots 



Inoculated with culture number 



Average number of nodules in 





Flowerpot 1 



Flowerpot 2 



Flowerpot 3 



28 



24.7 

 21.8 

 15.2 

 14.7 

 13.5 

 13.0 

 12.8 

 12.0 

 12,0 

 11.4 

 11.0 

 10.7 

 10.6 

 10.0 

 9.2 

 5.2 



7.8 

 8.4 

 6.2 

 8.0 

 6.6 

 7.2 

 1.7 

 6.0 

 4.7 

 5.6 

 6,2 

 5.5 

 4.6 

 5.2 

 3.8 

 1.6 



16.7 



31 



11.6 



21 



11.2 



17 



14.4 



7 



8.2 



38 



9.5 



43 • 



9.4 



18 



8.2 



41 



7.8 



45 





1 





8 



9.6 



2 



7.2 



44 



6.2 



34 



8.0 



6 



4.4 







The three flowerpots inoculated with culture 43 had 12.8, 1.7, and 9.4 

 nodules per plant, respectively. A similar relation exists between the 

 other flowerpots considered in table 14. If the efficiency of these cultures 

 were based on the number of nodules per plant, culture 43, for example, 



