764. DISCUSSION ON WHEAT: 
and with extremely susceptible varieties to determine whether the power of 
resisting disease would prove a unit character. In each case the hybrid 
plant proved susceptible to yellow rust, whilst its offspring consisted of 
immune and susceptible forms in the proportion of one of the former to 
three of the latter. In the many cases examined the segregation has proved 
to be exceedingly sharp. The property of resisting the attacks of yellow rust 
is thus shown to be a Mendelian recessive, and consequently all extracted 
immunes should breed true to this feature in succeeding generations. This 
point has now been tested many times, with concordant results in all cases. 
Further, the experiments have shown that immunity is independent of any 
recognisable morphological characters. Thus in the case of yellow rust there 
appears to be no valid reason why the plant breeder should not mitigate 
the evils of its attacks by using this knowledge as a basis for the production 
of resistant varieties. The attempts already made seem to show conclusively 
that this is practical. One example must suffice. From a cross between 
Square Head’s Master and a resistant variety found in Russian Ghirka 
wheat two very promising wheats, one immune and one susceptible, were 
isolated and grown on for comparison. In 1909, a moderately bad rust 
year, three-acre plots of these varieties were grown alongside one another. 
The susceptible variety gave one of the most striking plots of wheat on the 
experimental farm; the immune variety also grew into a good crop, though 
farmers visiting the station almost invariably preferred the former, in 
spite of its rustiness. At thrashing time, however, the effects of the attack 
became obvious, as the susceptible variety only yielded some forty-two 
bushels of grain per acre, as compared with fifty-four bushels per acre from 
the immune variety. The grain of the former was also so shrivelled that it 
was only fit for chicken food, whilst from the latter less than a half per 
cent. could be screened when dressing it for seed. 
If the attacks of yellow rust can be controlled in this manner it is 
reasonable to suppose that the still more serious black rust (Puccinia 
graminis) can also be brought under control. At the present time the most 
that can be said is that some evidence pointing in this direction has been 
obtained. The problem will, however, have to be solved elsewhere, for even 
with plantations of the alternative host, the Barberry, in the vicinity of the 
trial plots, we cannot count on a yearly epidemic of this rust to test the 
varieties thoroughly. 
4. Wheat Breeding in Canada. By Cuartes E. Saunpers, Ph.D., 
Cerealist of the Dominion Experimental Farms. 
On account of the vast extent and the varied climatic conditions of 
Canada, it is necessary to mention briefly the six chief sections into which 
the country may be divided on the basis of its wheat production. 
I. The Maritime Provinces: Nova Scotia, Prince Edward Island, and 
New Brunswick.—In these large tracts of country not very much wheat is 
grown. Most of the grain is sown in the spring, and the yields obtained 
are usually good, the kernels being plump, but rather soft and starchy. 
II. Quebec and Northern Ontario.—Spring wheat rather than winter 
wheat is usually grown, although the total quantity produced is not very 
great considering the numerical strength of the farming population. The 
kernels of the spring wheat produced in this section of Canada are usually 
somewhat smaller and harder than those grown in the Maritime Provinces. 
When the varieties which yield the strongest flour are sown, the wheat 
from this area is scarcely surpassed by that grown in any other part of 
Canada, though in appearance it is usually less attractive than the grain 
from the Western prairies. 
