Feb. 1923 Early Vigor, Yield, and Rot Diseases of Maize 
603 
Table XVIII.— Influence of moderately diseased and nearly disease-free seed on early 
vigor and yield of marketable corn of Reid Yellow Dent on very fertile soil to which rock 
phosphate and manure has been applied , at Urbana, III., in 1920 
Points considered. 
Number of plants in experiment. 
Early vigor: 
Percentage of kernels producing plants. 
Percentage of kernels producing vigorous 
plants. 
Percentage of kernels producing weak plants. 
Yield: 
Total acre yield (in bushels). 
Acre yield marketable com (in bushels). 
Percentage of nubbins (by count). 
Percentage of rotted ears (by count). 
Percentage of chaffy ears (by count)...._ 
Moder¬ 
ately dis¬ 
eased 
Nearly 
disease- 
free 
In favor of disease- 
free seed. 
com¬ 
posite. 
com¬ 
posite. 
Increase. 
Decrease. 
3 , 
4,281 
Per cent. 
Percent. 
80.3 
89.3 
II. 2 
25. 2 
39-4 
56-3 
36.9 
195 
12.3 
70.7 
78.7 
«• 3 
54-8 
68.2 
24. 5 
19 * 5 
14. 1 
27.7 
4.5 
3-3 
26. 7 
8-5 
4.3 
49-4 
The same standard for vigorous plants was maintained in taking the 
data reported in Tables XVIII, XIX, and XX. In the experiments 
reported in Table XX there was little apparent difference in vigor or gen¬ 
eral appearance in the early stages of growth between the rows grown 
from diseased and nearly disease-free seed. However, it was evident 
upon close examination that the plants in plots planted with nearly 
disease-free seed were somewhat larger in circumference at the base and 
also sturdier. The increase in yield from the better seed is very marked, 
even in heavily infested soil. Such results suggest that the nearly 
disease-free seed may have possessed some degree of resistance to the 
root and stalk rots. 
Table XIX. —Influence of moderately diseased and nearly disease-free seed on early vigor 
and yield of marketable corn of Reid Yellow Dent on soil of average fertility, limed and 
phosphated, at Urbana, III., in 1920 
Points considered. 
Number of plants in experimentj. 
Early vigor: 
Percentage of kernels producing plants. 
Percentage of kernels producing vigorous 
plants.. 
Percentage of kernels producing weak plants. 
Yield 
Total acre yield (in bushels). 
Acre yield of marketable com (in bushels)... 
Moder¬ 
ately dis¬ 
eased 
Nearly 
disease- 
free 
In favor of disease- 
free seed. 
com¬ 
posite. 
com¬ 
posite. 
Increase. 
Decrease. 
3.847 
4, 263 
Percent. 
Percent. 
80. 2 
88.8 
10. 7 
9.6 
19. 1 
99.0 
30-5 
22. 9 
24.9 
67.7 
79-4 
17.3 
59 - 6 
74 . 1 
24.3 
