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It was further found that Feterita plants showed a definite 
effect of inoculation. Uninoculated plants produced normal 
heads but, if the plants were inoculated, approximately 50 per 
cent. of them failed to produce normal heads, the flower buds 
being blasted, and very little, if any, grain produced. Some- 
times smut balls were found on the blasted heads, showing that 
the smut mycelium had developed in the plant, reaching the 
stage of spore formation. Occasionally, a typically smutted 
head was observed, as in other years. A few blasted heads of 
Feterita had been observed in previous years, and this peculiar 
effect upon this variety is especially important in interpreting 
the results with the hybrids. The inoculated Milo plants, as in 
previous seasons, showed no evidence of infection. While 
Feterita, under usual conditions, may be classified as a resistant 
variety, it is evidently genetically quite different in its response 
to that of the Milos. 
During the past year, a considerable number of first generation 
plants were inoculated with the covered smut. The first genera- 
tion plants of crosses between Feterita and susceptible varieties 
were infected. The first generation plants of crosses between 
two susceptible varieties, such as Dawn Kafir and Red Amber 
Sorgo, also were infected. The first generation plants of crosses 
between Milo and susceptible varieties remained normal. 
A large number of second generation plants of crosses of three 
different types, based on the behavior of the parental varieties, 
were grown. In the cross between Feterita and Dwarf Yellow 
Milo, occasional smutted and blasted plants were observed in 
contrast to previous years, when none was recorded. 
In the second generation of hybrids between susceptible 
varieties and Feterita, a large percentage of the second generation 
plants were either blasted or infected, 50 to 77.5 per cent. having 
typical smutted heads. The results clearly indicate that suscepti- 
bility is dominant. On the other hand, when these varieties are 
crossed with the Milos, no blasted heads appear in the second 
generation, and there is a low percentage of infection, ranging from 
13.7 to 25 per cent. It is evident that the Milo factor of resis- 
tance is very different from that of Feterita. A hybrid between 
two susceptible varieties, Dawn Kafir and Red Amber Sorgo, 
gave 100 per cent. infection in the second generation. 
ear 
