n8 
Journal of Agricultural Research 
Vol. XIV, No. 2 
uredinia appeared on leaf blades and sheaths, as well as on the fasciated 
glumes, and the plant was without doubt susceptible. The two series 
of inoculations, one from the stock cultures and the other from this 
hybrid plant, made on seedlings of Haynes Bluestem (Minnesota 169) 
gave similar results. In both series numerous uredinia appeared in the 
usual time and developed to normal size. There was, however, no 
evidence that Bluestem wheat was any more susceptible than when 
inoculated with rust from other plants of the same variety (PI. 14, A, B). 
Two series of inoculations made on seedlings of the somewhat resistant 
parent, Kubanka (Cl 2094) also failed to reveal any differences in degree 
of infection resulting from the source of the inoculum. Although ure¬ 
dinia were formed on all leaves inoculated, many of them were smaller 
than those on the susceptible variety and sharp flecks were nearly always 
present, indicating at least some resistance. There was no evidence 
whatever that Kubanka (Cl 2094) was more susceptible to the rust from 
the hybrid than to rust from any other source (PI. 14, C, D). 
Table II.— Results of inoculations with P . graminis tritici on resistant and susceptible 
parents with rust from susceptible F 2 hybrid and from stock cultures 
Source of rust. 
Plant inoculated. 
Result. 
Character of infection. 
Stock cultures.... 
Marquis. 
49 
Very heavy; large uredinia. 
49 
F 2 hybrid... 
B 
Do. 
Nearly immune; no uredinia; 
very small, light green flecks. 
Stock cultures.... 
Emmer (Minn. 1165) • 
51 
0 
54 
F 2 hybrid. 
0 
Do. 
61 
Table II shows the results of inoculations with the rust from the F 2 
hybrid, White Spring emmer (Minnesota 1165) X Marquis, on seedlings 
of the two parent varieties, and furnishes the most convincing evidence 
that this particular susceptible hybrid does not increase the virulence 
of the rust for either parent variety. Normal uredinia on the hybrid 
plant shown at A in Plate 15, furnished the spore material used to inocu¬ 
late the seedlings of susceptible Marquis and the extremely resistant 
emmer parents. On all the seedlings of Marquis, normal infection 
resulted, both from inoculations made with rust from stock cultures, and 
with those from the susceptible hybrid. There was no observable differ¬ 
ence in number or size of uredinia. Neither were there any indications 
of resistance, nor of increased susceptibility in those plants inoculated 
