4 BULLETIN 1062, U. S. DEPARTMENT OF AGRICULTURE. 
With increased starchiness a number of factors operate toward 
increasing the number of ear infections. Immature seed ears are 
characterized by starchiness. Some of the starchy ears may come 
from the normally late-maturing strains, in which case the ear is 
exposed to weather conditions more favorable for infection by the 
root-rotting organisms during the period of ripening. Because of 
their high moisture content, such immature ears afford a good me- 
dium, even after harvest, for the development of these organisms 
when introduced from external sources. It has already been ob- 
served, however, that larger percentages of ear infection occur in 
the starchy groups of seed ears from strains with practically the 
same length of growing season. Field observations indicate that 
such seed ears are obtained from stalks suffering from an unbal- 
anced food supply. Perhaps the main contributing factor is a root- 
rotted condition of the parent stalk itself. These factors merely 
furnish additional argument in favor of the practice of selecting 
seed ears from the stalk in the field. 
RELATION OF KERNEL STARCHINESS TO PATHOLOGICAL 
PERFORMANCE. 
As starchy seed ears are more frequently infected with root-rot 
organisms than the more horny ears, it has seemed important to de- 
termine the relation of kernel starchiness to pathological perform- 
ance in the field. Decreased stands and yields follow the planting 
of kernels from infected seed ears, as has been determined by the 
writer and by Duddleson and Hoffer 2 (unpublished data) and pre- 
viously reported in the course of these investigations by Hoffer and 
Holbert. 3 
Because of the larger proportion of infections in the starchy seed 
ears, the planting of seed from these two groups without regard to 
the germination records would be expected to show superior yields 
from the more horny seed. In the study of the field effects of ear 
infection during the seasons of 1918, 1919, and 1920, approximately 
equal numbers of infected and of disease-free ears from the horny 
and the starchy groups were used in ear-to-row experiments. All 
rows were 75 hills in length. Only ears giving 100 per cent germina- 
tion in the laboratory were used for seed. 
The data from these plats have been summarized in Table 2 on 
the basis of starchiness of kernels. In this table the field perform- 
ance of the horny groups of ears in each experiment has been taken 
as 100 per cent. The figures represent the percentage of decrease 
incurred through the use of the starchy seed ears. In all but one 
2 Duddleson, B. H., and Hoffer, G. x. The improved rag-doll germinator for the 
elimination of diseased seed corn. (Manuscript.) 
3 Op cit. 
