RUST RESISTANCE IN WINTER-WHEAT VARIETIES. 13 
All varieties of soft red winter wheat were found to be susceptible 
to stem rust. Plate V, A shows a typical plant of Mealy, a very 
susceptible variety. 
Several of the varieties of spring wheat showed een of being 
resistant. Other varieties, such as Ghirka Spring (PI. V, B), were 
found to be very peecoe nie. Black Persian was the jake variety 
of common spring wheat which showed marked signs of resistance. 
Among the durum wheats, Beloturka (C. I. No. 1513), Iumillo 
(C. I. No. 1736), Kubanka (C. I. No. 2094), Monad (C. I. No. 3320), 
and D-—5 (C. I. No. 3322) all proved rather resistant to stem rust. 
A hybrid between Iumillo and Preston (No. 3 X 122A12) also was 
very resistant. This hybrid resembles the durum parent in type of 
head. 
All of the strains of emmer gave some evidence of being resistant, 
as did the one strain of einkorn. Khapli emmer (C. I. No. 4013), 
although slightly rusted, never showed the large linear uredinia 
which develop on susceptible varieties. 
Usually a rather close relationship is shown between the extent 
of stem rust recorded and the quality of grain produced by a given 
variety. The grain of certain varieties, however, sometimes is 
severely injured by a medium quantity of rust, while other varieties 
with a higher percentage of rust infection will produce heavier grain. 
Kanred, P1066, and P1068 were all low in quantity of rust in 1916 
and 1917, and all produced good heavy plump kernels. Factors 
other than rust infection, of course, influence grain quality, but it 
was very evident in 1916 and 1917 that the three rust-resistant 
varieties produced better grain than the similar but more severely 
rusted varieties grown in near-by rows. 
Typical kernels of resistant and susceptible varieties produced in the 
wheat-rust nursery in 1916 and 1917 are shown in Plate VI. Table 
2 presents data showing the percentage of rust infection on the 
varieties of which kernels are shown in Plate VI. The letters in the 
first column of the table correspond with those of figures 1 and 2 of 
the plate. 
