The Regional Adaptation of Corn in Nebraska 
57 
stomata are somewhat shorter while the leaf and epidermal 
thickness are practically identical. Stomata are more numerous 
and in general the cell size is somewhat smaller. 
Probably the actual hereditary differences existing between 
types adapted to favorable and to unfavorable climatic con- 
ditions may be best determined by growing them all compar- 
atively in the same environment under favorable conditions. In 
general when grown in eastern Nebraska, (Lancaster County), 
western Nebraska corn was markedly smaller in size of plant, 
leaf area, and plant substance than was eastern Nebraska corn. 
On the other hand, the leaf thickness, epidermal and cuticular 
thickness, relative number of vascular bundles, number of sto- 
mata per unit leaf area, and size of stomata were rather similar 
for corn of both sources. The data suggested that a slightly 
smaller stomatal aperture associated with a somewhat smaller 
epidermal cell is characteristic of the short season dry land types 
of western Nebraska. This would not seem to be of any adaptive 
importance because the reduction is insufficient to act as a check 
upon transpiration, as may be seen in Table 30. 
COMPARATIVE YIELDS OF NATIVE TYPES 
During 1916 and 1917, the native corn types from various 
parts of the state were compared for yield at the Experiment 
Station. Yields were based on the center row of duplicate three- 
row fifteenth-acre plats in which only hills with a full number 
of plants, three per hill, and surrounded by a full stand, were 
harvested. The results are given in Table 29. The average 
yields for eastern, central and western Nebraska types for the 
tAvo years were respectively : 59.8, 46.2, and 31.6 bushels per acre. 
The corresponding maturity dates were September 24, Septem- 
ber 21, and September 12. 
No attempt has been made in connection Avith these iiwesti- 
gations to make a reliable comparative yield per acre test for the 
various nath T e corn types. Such a test Avould inA’oNe the grow- 
ing of each type at several different planting rates for a period 
of years in order to determine the optimum rate for each, and 
to average seasonal effects. f In any embroilment as a general 
rule the maximum yield is obtained for the smaller and earlier 
types at a thicker planting rate than for the larger, later matur- 
ing types. Tests of this sort haA^e almost uni A^er sally been made 
at a single arbitrary planting rate which is likely to be too thin 
for the smaller types when compared under fa Adorable groAving 
conditions, and too thick for the larger types AA*hen compared 
tKiesselbach, T. A., 1918, Nebraska Agricultural Experiment Station Research 
Bulletin No. 13, pp. 45-47. 
