72 
Journal of Agricultural Research voi. xxvn, no. 2 
EXPERIMENTAL DATA 
ROOT ANCHORAGE STUDIES 
The results presented in Table I were secured under very uniform 
conditions. Previous to planting the corn, the large soil pit in one of 
the greenhouses at the University of Illinois was refilled with new soil 
which had been thoroughly mixed. Although plants of the strain sus¬ 
ceptible to rootrot had not been exposed to wind and storm and had 
equal opportunities to develop a strong root system, yet the mean pull 
of these plants was less than half that of plants of the good strain, 
13.8 ± 1.1 pounds compared with 29.8 ± 1.8 pounds, respectively. Plants 
of the strain susceptible to leaf firing offered less than one-third the 
resistance to a vertical pull that was exhibited by plants of the good 
strain, 9.1 ±0.9 pounds compared with 29.8±1.8 pounds, respectively. 
There was no material difference in the height of plants of these three 
strains on the date when the plants were pulled. None of the roots 
showed any evidence of root rotting. Leaves of the strain susceptible 
to leaf firing apparently were normal in every respect. In view of such 
facts, the differences of 16.0±2.1 pounds and 20.7 ±2.0 pounds in root 
anchorage are very significant. The two first generation hybrids were 
somewhat more vigorous than the good inbred strain as measured by 
vegetative growth, but they were not superior in pulling resistance. 
These data suggest that the genetic factors responsible for the reduced 
root systems in the strains susceptible to rootrot and leaf firing, respect¬ 
ively, are recessive. Repeated field experiments not herein reported 
confirm this suggestion. 
The plants of a number of inbred strains were pulled after they had 
matured in field plats, but while the stalks were still green. The results 
given in Table II show that erect plants of the good strain were better 
anchored than erect plants of the strain susceptible to rootrot. The 
difference of 48.6 pounds, or 23.4 per cent, with odds of 132:1, is suffi¬ 
ciently large to be significant. 
Table I .—Data on the root anchorage of three unrelated selfed strains of Yellow Dent and 
three F x crosses measured by their resistance to a vertical pull , the corn being planted 
Mar. 8 y 1922 , in the greenhouses of the University of Illinois and pulled May 6, 1922 
Character of inbred strains and crosses. 
Num¬ 
ber of 
plants 
pulled. 
Mean pulling 
resistance 
per plant. 
Difference in pulling 
resistance based on 
good strain. 
Difference 
P. E. 
Good. 
23 
22 
25 
26 
26 
Pounds. 
29.8±I.S 
I3*8±i.i 
9. iibo.9 
29.4^1.6 
28.3 ±1.6 
Pounds. 
Per cent. 
Susceptible to rootrot. 
Susceptible to leaf firing. 
Fj (Good x rootrot susceptible). 
Fj (Good x leaf firing susceptible) 
l6.0±2.1 
20. 7±2.0 
• 4±2.4 
i-5±2.4 
53-7 
69-5 
i -3 
5-o 
7.6 
IO.3 
.2 
•7 
