May 15, 1925 
Inheritance of Botanical Characters in Barley 
923 
Table YI. — Distribution of plants for the characters black glume and white glume 
in the F 2 generation of the crosses Hordeum deficiens steudeliiX Manchuria and 
Svanhals X Lion 
Year 
grown 
Black- 
glumed 
White- 
glumed 
Total ; Cross 
1922_ 
263 
92 
| 
355 observed - _ .1 H. deficiensXManchuria. 
266. 25 
88. 75 
355 calculated ...__ _ 
3. 25 
Deviation J 
5. 5 
Probable error i 
1923_ 
470 
138 
608 observed __ ! 
456 
152 
608 calculated_| 
14 
Deviation - i 
7. 2 
Probable error 
1922_ 
871 
283 
1,154 observed__ SvanhalsXLion. 
865.5 
288. 5 
1,154 alculated__ 
5. 5 
Deviation.. ! 
9.9 
Probable error.. ... 
1923_ 
360 
120 
480 observed_ 
360 
120 
480 calculated_ 
0 
Deviation.. . 1 
6.4 
Probable error ... j 
Table VII .—Behavior of F 3 lines from plants classified in F 2 as black qlumed, in 
the crosses Hordeum deficiens steudeliiX Manchuria and SavanhalsXLion 
Breeding 
true for 
black 
Segregat¬ 
ing in 3:1 
ratio 
Total 
Cross 
24.0 
41.0 
65. 0 observed... _ 
j 
21. 7 
43.4 
65.1 calculated___ 
Ih. deficienssteudelii X 
2.4 
Deviation_ 
| Manchuria. 
2.6 
Probable error_ 1 
J 
25.0 
58.0 
83.0 observed_ _ I 
1 
27.7 
55.4 
83.1 calculated_ 
1 SvanhalsXLion. 
2.6 
Deviation_ , 
2.9 
Probable error_ 
i 
J 
Black versus white glumes.— 
The glumes of plants of the Fi genera¬ 
tion in the crosses Hordeum deficiens 
steudeliiX Manchuria and Svanhals 
X Lion are as black as the colored 
parent. In the second generation the 
ratio of plants with black color to 
plants that are white is verv close to 
3 : 1 (see Table VI). Alf white F 2 
plants bred true for white in F 3 , as 
expected. Sixty-five F 3 lines from one 
cross and 83 from the other were 
grown from plants classed as black in 
F 2 - The deviation from the expected 
1 : 2 ratio is less than the probable 
error in each case (see Table VII). 
Apparently black and white differ by 
a single factor pair. 
Rough awn versus smooth.— 
Rough-awned varieties of barley are 
very disagreeable to handle, and for 
this reason the smooth-awn character 
is of considerable practical importance 
for those regions where awned varieties 
are preferred. The cross SvanhalsX 
Lion gave Fi plants with awns as 
rough as those of the Svanhals parent. 
The F 2 plants were easily classified 
into two groups, the first with awns 
entirely rough and the second with 
awns partially or almost entirely 
smooth. All plants which had awns 
with any degree of smoothness were 
studied carefully, the awns being 
examined under magnification. An 
index for smoothness was derived in 
a similar manner as in previous studies 
at the Minnesota station (10) which 
briefly is as follows: The total length 
of the awn in centimeters is divided 
by the portion of the awn from the 
tip where there are teeth of large size 
at frequent intervals. The higher the 
index of smoothness the smoother the 
awn, and vice versa. A rough awn 
has an index of 1 while the Lion parent 
used in this study has an average 
index slightly above 3. Some plants 
of Lion have a few scattered teeth, 
about half the distance from the tip 
to the base of the awn, but these 
teeth are usually of slightly reduced 
size. 
An arbitrary division was made at 
an index of 2 and plants with a higher 
index were called smooth while plants 
with a lower index than 2 but with some 
degree of smoothness were called 
