Sl 
that penetration of the parasite might be secured. Then, during 
the further growth of the plants, various modifications in the 
nutrition were made. Asa result, some of the plants were small, 
and dwarf, as compared with the vigorous tall, branching, ones in 
the experiment. All of the cultures, however, showed practically 
the same percentage of infected individuals. In other words, the 
most effective factors influencing the appearance of smut in the 
plant are those involved in the very early seedling stages when 
infection occurs. After the smut fungus once gains entrance into 
the plant, the subsequent rate and amount of growth of the latter 
does not appear to prevent the final development of the parasite in 
the flowers. 
Sorghum Sinut Investigations 
— 
Studies were continued in connection with the covered kerne 
smut of sorghum, Many second generation progenies of different 
crosses of sorghum varieties were inoculated and grown to ma- 
turity. The hybrids involyed various combinations of resistant 
and susceptible varieties. 
‘ 
During the past year, a paper on “ A new method of producing 
7) 
and detecting sorghum hybrids ” was published and, in this paper, 
some of the data on the inheritance of smut resistance were 
recorded. 
The method is based on the fact that the seedlings of sorghum 
hybrids differ in color, some being green, while others are red or 
reddish purple. It is further observed that among the hybrids 
of green seedling and red seedling varieties, the red character is 
dominant. These two observations suggested a method of obtain- 
ing and detecting hybrids between certain varieties with compara- 
tive ease. 
The procedure was to use the green seedling variety as the 
female parent. The young flowers of such a plant were pollinated 
with the po 
— 
len from a red seedling variety, the operation being re- 
peated at intervals as long as the flowers continued to open on the 
green seedling parent. 
— 
It was expected that most of the flowers on the female plant 
would actually be selfed, due to the relative abundance of pollen 
from other flowers on the same head. It was assumed, however, 
that the foreign pollen of the red seedling variety would reach the 
