Aug. 26, 1918 
Variation and Correlation in Wheat 
377 
the somewhat higher productivity of the soil, and (c) the higher mean 
and greater range in weight of seed planted. 
Correlation coefficients for number of days from planting to second 
leaf were determined in 1916 and 1917 only. The correlation coefficients 
are relatively high, indicating that the plants from the heavier seeds 
reach the second leaf 
stage sooner than the 
plants from the lighter 
seeds. Correlation is 
highest in 1917, the 
year in which the mean 
weight of the seed was 
the lowest. 
Weight of seed cor¬ 
related with height of 
plants at second leaf 
gave coefficients vary¬ 
ing from o.H4±o.027 
in 1915 too.259io.028 
in 1917 and correlated 
with height at six 
weeks, a variation from 
0.356±0.040in 1914 to 
0.712±0.015 I 9 I 7- 
In each of the four years 
the coefficients as com¬ 
pared with their proba¬ 
ble errors show a fair 
correlation for height at 
second leaf and a con¬ 
siderably higher corre¬ 
lation for height at six 
weeks. This indicates 
that at the appearance 
of the second leaf the 
greater food supply available to the plants from the larger seeds had not 
yet exerted its influence. An extreme difference of 0.145 ±0.038 * m the 
coefficients for height at second leaf and 0.356±0.042 for height at six 
weeks during the 4-year period shows that correlation between weight of 
seed and both of the characters was influenced considerably by environ¬ 
ment. 
Between weight of seed and height of tallest culm at maturity the 
correlation coefficients are — o.037±0.028 in 1915, 0.074±0.030 in 1917, 
o.i96±o.037 in 1914, and 0.311 ±0.023 in 1916. As indicated by the 
y/SLO //V 
