WINNIPEG, 1909. 763 
with one another. If this view be correct, the combination of heavy yield 
with strength is an impossible one. At present little evidence can be 
brought forward from one side or the other, though it is worth noting that 
in some few districts in England Red Fife crops as well as Square Head’s 
Master. Such fresh evidence as can be brought forward at this stage points, 
however, to the incorrectness of the general view, and seems to show that a 
heavy crop of good quality is by no means an impossibility. 
The best proofs of its possibility or otherwise would be afforded by a 
detailed study of the inheritance of yielding capacity, a matter on which 
it must be admitted we know little at present. That it is a unit 
character is perhaps indicated by the fact that some varieties are con- 
sistently heavier yielders than others even under a wide range of variation 
in the conditions. For instance, Square Head’s Master has, on this account, 
gradually driven such varieties as Red Lammas, Chiddam, Talavera, &e., 
practically out of existence. Further, the cultivation of a long series of 
hybrids between heavy and comparatively low yielding wheats seems to 
point to segregation of these features. Exact statistics, however, are very 
difficult to obtain owing to the wide range of fluctuating variability in this 
character and the difficulty of growing plants under sufficiently uniform 
conditions to eliminate this. Even when the outer rows of an F., culture 
are neglected as consisting of obviously favoured plants, gaps, due to 
failures in germination or the attacks of mice, &c., give neighbouring plants 
a greater root range and better opportunities for development than others. 
In the absence of such information one has to fall back on the yields of 
the plots grown from the F., generation and then on the crops of succeeding 
years, basing conclusions as far as possible on plots of sufficient acreage 
to give trustworthy returns. For this purpose the Fife hybrids mentioned 
previously are fairly suitable, as under the conditions under which these 
experiments were made Fife barely yields twenty bushels to the acre, whilst 
Rough Chaff may be expected to give a good average yield of thirty-two 
bushels. 
In making the selections for further cultivation these strong types, 
promising to give the best yield, were deliberately chosen. Some forty of 
these, which have been tested in plots varying from one-quarter to three 
acres in extent, have given in each case yields of the same order as the 
parent Rough Chaff and over 50 per cent. greater than Red Fife on the same 
farm. On other soils some grown on the large scale have produced crops 
of forty-two to forty-four bushels, but in these cases the cropping capacity of 
Rough Chaff is unknown, though Fife is known to be a failure as regards 
yield. The evidence for the segregation of high and low yields is by no 
means final, but it is sufficient to show that high yields of good quality 
are not unobtainable. 
The question of heavy yields per acre is intimately connected with the 
power of resisting the various diseases to which the wheat crop is liable, as 
no plant crippled by the attacks of a parasite can be expected to yield its 
full quantity of grain. It is a well-known fact that if a large number of 
varieties of any plant grown under the same conditions are exposed to the 
same chances of infection they show marked differences in the extent to 
which they become attacked by various parasites. This is well shown in the 
case of wheats and the various rusts which live upon them. In fact, it has now 
become part of the routine work of many experimental stations to collect 
and grow as many varieties as possible, with the view of selecting the most 
immune types for local cultivation. In our earlier tests several varieties 
were found showing an extraordinary power of resisting the attacks of the 
common yellow rust, Puccinia glumarum. Even in years when the rust 
attack has been at its worst they have shown only the merest traces of 
infection. Such immune varieties were at once crossed both with moderately 
