EUST 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 evidence of being 

 resistant. Other varieties, such as Ghirka Spring (PI. V, 5), were 

 found to be very susceptible. Black Persian was the only variety 

 of common spring wheat which showed marked signs of resistance. 



Among the durum wheats, Beloturka (C. I. No. 1513), lumillo 

 (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 lumillo 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. 



