84 



Presoaking of Seeds and Its Effect upon I u feet ion. - -When seeds 

 of certain sorghum varieties arc soaked for 48 hours the seedlings 

 are retarded in growth, particularly when there are frequent 

 changes of water during the soaking period. Thai substances are 

 dissolved out of the seed coals is evident when colored seeds are 

 employed, the water used for soaking taking on more or less 

 coloration, in carrying out certain experiments, precautions must 

 be taken in order to keep other factors as uniform as possible. 

 The results secured with the covered smut indicated that the re- 

 sistant varieties Dwarf Yellow Milo and Standard Yellow Milo 

 produced no smutted plants. The susceptible varieties Red Amber 

 Sorgo and Dawn Kafir showed differences in infection percentages, 

 depending upon the type of seed treatment. Red Amber Sorgo 

 gave 66 per cent, infection for the controls, 67 per cent, for the 

 soaked svec\. and 73 per cent, for the soaked seed, with changes of 

 water. Another set of plants was germinated in sand to which a 

 sucrose solution was added, the corresponding percentages being 

 82, 91, and 96. For Dawn Kafir, 56 per cent, of the controls 

 were infected, 100 per cent, for the soaked seeds, and 65 per cent, 

 for those soaked, with changes of water. Somewhat similar re- 

 sults were obtained with two susceptible varieties, inoculated with 

 the loose smut. Feterita, a variety resistant to the loose smut, 

 remained entirely free while Milo, which infrequently produces 

 a smutted plant, gave a small percentage of infected plants in the 

 series where the seeds had been presoaked. It is clear that the 

 presoaking of seeds, particular!}' with frequent changes of water, 

 is conducive to increased infection in susceptible varieties. 



Influence of Water Extracts from Seeds upon Infection— No 

 evidence was obtained to indicate that water-soluble substances. 

 present in the seed coats of resistant varieties of sorghum, might 

 be inhibilive of infection. The susceptible varieties continued to 

 give very high percentages of infection. When the seeds ol re- 

 sistant varieties were soaked in such solutions from susceptible 

 varieties, no infection occurred. 



Smut Results with Sorghum Hybrids. — In hybrids involving 

 Feterita with some other varieties, a considerable number of so- 

 called " blasted " plants are observed. A series of second gen- 

 eration plants of certain hybrids was grown, one set of seed 

 having been germinated at 17.5° and the other at 27.5" ('., other 



