Corn Investigations 
61 
these selections tended strongly to come true to type, tho there 
was still considerable variation between the individual plants. 
The comparative growth characteristics of these different selec- 
tions before inbreeding is shown for 1909 in Table 19. 
Comparing the average of the low leaf area selections with 
the average of the high leaf area selections, the former had 82 per 
cent as much leaf area per gram dry matter, 77 per cent as 
much actual leaf area, 95 per cent as much total dry matter, 99 
per cent as great ear weight, grew two inches shorter, and ma- 
tured five days earlier. These comparisons were all based on 
individual measurements of ten representative plants for each 
strain. In addition to the above differences, a very distinct 
difference in ear type had unconsciously been developed for the 
two general groups. The low leaf area selection had a more 
slender ear, with shallower and flintier kernel, than the orig- 
inal variety. The high leaf area selections, on the other 
hand, were characterized by a somewhat larger ear circumfer- 
ence and a deeper and rougher kernel. 
INBRED STRAINS 
During the six years 1909-1915 (omitting 1918), these 8 
high and IT low leaf area strains were subjected to continuous 
self-fertilization. The comparative growth at the end of this 
period of reduction to elemental strains is shown in Table 20, 
which gives the averages for the two years 1915-1916. Compar- 
ing the average of the low leaf area pure lines with the average 
of the high leaf area pure lines, the former had 84 per cent as 
much leaf area per gram dry matter, 76 per cent as much actual 
leaf area, 94 per cent as much total dry matter, 125 per cent as 
great ear weight, grew 2 inches taller, and matured 5 days 
earlier. 
In the more important characteristics, practically the same 
relationships obtained between the two groups of pure lines as 
existed before self-fertilization. However, a great reduction in 
plant size and productivity had resulted from the continuous 
self-fertilization. 
HYBRIDS BETWEEN LEAF AREA PURE LINES 
During 1915 and 1916 a comparative yield test was made of 
(1) 18 F 1 hybrids between low leaf area pure lines, (2) 4 F t 
hybrids between high leaf area pure lines, (8) 7 F T hybrids 
between high and low leaf area pure lines, and (4) original 
Hogue’s Yellow Dent corn. The results are given in Table 
No. 21. 
