42 
susceptible parent, Sumac Sorgo, and no infection of the resistant 
Feterita. The third generation families have shown great varia- 
tion in the amount of smut, some being entirely resistant, while 
others are very susceptible, and the morphological characters of 
the two parents are variously combined with the quality of smut 
resistance or susceptibility. 
The cross between White Milo and Blackhull Kafir seems to 
indicate that resistance is dominant and susceptibility is reces- 
sive. During the past season 17.1 per cent. of the second genera- 
tion plants were infected, as compared with 47.7 per cent. ot 
Blackhull Kafir and no infection of the White Milo. The in- 
fection of the Blackhull Kafir varied greatly in the different ex- 
periments, the highest obtained being 66 per cent. In the third 
and fourth generations we find various combinations of charac- 
ters, several greatly resembling Blackhull Kafir, but showing a 
high degree of resistance. 
A very serious difficulty in the study of this problem has been 
that of securing infection of the maximum number of suscep- 
tible plants. We have not been able to devise methods for use 
on a large scale which are successful in securing the infection ot 
all susceptible individuals. During the past year, Sumac Sorgo 
las given a higher infection than usual, while, on the other hand, 
the results with the Blackhull Kafir have been below those of 
previous years. 
— 
Additional crosses between various sorghums have been made. 
and the first generation was grown during the past season. The 
second generation will be available for study during the coming 
year. 
Head Smut of Sorghum and Corn 
This fungus is particularly interesting because of its occurrence 
on both sorghum and corn. The studies reported upon last year 
have been continued. Various methods have been employed to 
secure infection, which have involved for the most part varia- 
tions in the age of seedlings and in the culture of spores in the 
soil. Various combinations of spore-soil cultures and seedlings 
of different ages have been carried out. Unusually severe in- 
fections of corn with spores from corn occurred throughout a 
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