INHERITANCE IN THE BARLEY SPIKE. 
19 
Table III. — Homozygous -plants of selection 448-9 of the Hanna-Zeocriton eross, F± 
generation. 
F< line. 
Number of 
individuals. 
Mean. 
Coefficient of 
variability. 
448-9-4 
63 
16 
59 
Millimeters. 
2.06±0.01 
3.41± .04 
4.30± .02 
6.80±0.41 
448-9-19 
7.33± .87 
4.65± .29 
448-9-30 
The mean of 448-9-19 is not as reliable as of the other two lines, 
as only 16 individuals were available for the study. 
Selections 448-7 and 448-13 appear heterozygous in the F 3 genera- 
tion and have about the same degree of frequency range. The coeffi- 
cients of variability are much smaller than in F 2 , but are significantly 
larger than in the pure parental forms. The frequency range for 
448-7, of which 39 plants were studied, was from 2.0 to 3.2 mm. 
Two plants from each of these lines gave evidence of being homozy- 
gous in F 4 . These are shown in Table IV. 
Table IV. — Homozygous 
of selections 448-7 and 448-13 of the Hanna-Zeocriton 
cross, F 4 generation. 
F 4 line. 
Number of 
individuals. 
Mean. 
Coefficient of 
variability. 
448-7-1 
107 
102 
64 
57 
Millimeters. 
2.21±0.01 
3.12± .01 
3.19± .02 
4.15± .02 
7.69±0.35 
448-7-3 
5.77± .27 
448-13-2... . v 
6.27± .37 
448-13-5 
4.58± .29 
Four of the 20 F 2 plants which were tested in F 3 appeared to give 
homozygous progeny. Three of these proved to be homozygous by 
further test, while one, 448-11, proved heterozygous. The F 4 lines of 
interest which seem to be homozygous are shown in Table V. 
Table V. — Homozygous plants of selection 44i 
generation. 
-11 of the Hanna-Zeocriton cross, F A 
F4 line. 
Number of 
individuals. 
Mean. 
Coefficient of 
variability. 
448-11-2 
73 
45 
Millimeters. 
3.08±0.01 
3.69± .02 
5.52±0.31 
448-11-3 , 
4.34± .31 
The three lines of especial interest which appeared homozygous by 
both the F 3 and F 4 study are as follows: 448-1, mean 2.30 ± .01 mm.; 
448-5, mean 2.88 ±.01 mm.; 448-16, mean 4.30 ±.01 mm. The F 4 
generation means are given for these lines, as they are based upon 
larger numbers than the F 3 test. Typical spikes of the parent 
varieties and of these lines are shown in Plate II. 
