May 15, 1925 
Inheritance of Botanical Characters in Barley 
927 
Table XIV .—Correlation of the Helmin¬ 
thosporium figure in series I and II of 
135 Fz families; cross SvanhalsX 
Lion , 1923 
This figure, while not high, shows 
that definite differences exist between 
the F 3 lines and that these differences 
tend to appear alike in both series. 
The probable error calculated by the 
“deviation from the mean” method 
(9) was 4.7 per cent. With the prob¬ 
able error of the experiment as 4.7 
per cent, the probable error of a differ¬ 
ence is 6.6 per cent. If one considers 
three times the probable error of a dif¬ 
ference as significant, then a difference 
in Helminthosporium reaction to be 
of importance must be three or more 
in the more susceptible lines and five 
or more in the resistant lines. 
The numerical figure for Lion was 
13.1 and for Svanhals 23.6 (Table 
XV). The F 3 lines varied in their 
reactions, some being as resistant as 
Svanhals while others were as suscep¬ 
tible as Lion. The distribution of the 
lines fits a normal frequency curve 
fairly well. From these data alone no 
definite conclusions can be drawn as 
to the number of genetic factors con¬ 
cerned in the production of resistance. 
It is of interest, however, to consider 
the reaction to Helminthosporium in 
relation to other characteristics. (See 
under “Linkage relations.”) 
INDEPENDENT INHERITANCE 
Black versus white and two- 
rowed versus six-rowed. —In the 
cross Svanhals X Lion, the character 
pair 6-rowed versus 2-rowed was shown 
to be differentiated by a single factor. 
The same was shown to be the case for 
the character pair black versus white. 
Likewise, in the cross Hordeum deficiens 
steudelii X Manchuria the character 
pairs deficiens versus 6-rowed and 
black versus white were shown each to 
be differentiated by a single factor pair. 
The relation of the character pair 
2 -rowed or deficiens versus 6-rowed to 
the character pair black versus white is 
shown in Tables XVI and XVII. In 
the cross H. deficiensXManchuria the 
factors for the characters deficiens and 
black went into the cross together and 
in the cross Svanhals X Lion the factor 
for 6-rowed went in with the factor for 
black. The results show the character 
pairs 2-rowed or deficiens versus 
6 -rowed and black versus white to be 
independently inherited. 
Table XV .—Helminthosporium reaction of F 3 lines and parent varieties in the 
cross SvanhalsXLion 
Helminthosporium index 
Total 
Average 
12 15 1 18 
21 
24 
27 
Svanhals_ i_ 1 _ 
Lion _ . .... __ 9 5 _: 
3 
10 
1 
14 
14 
135 
23. 6±0. 03 
13. 1±0.02 
18. 6 
F 3 families_ 6 31 42 j 
] 
43 
12 
1 
Table XVI .—Distribution of F 2 plants for the characters deficiens versus six-rowed 
and black glume versus white. Hordeum deficiens steudeliiXManchuria 
Deficiens 
and 
interme¬ 
diate 
black 
Deficiens 
and 
interme¬ 
diate 
white 
Vulgare 
black 
! Vulgare 
white 
1 
Total 
| 
Y ear 
grown 
211 ! 
52 
60 
32 
i 1 
! 355, observed_ - -! 
} 1922 
200 
67 
67 j 
22 
! 356, calculated on 9 :3 :3 :1 basis_ 
X 2 =8.81. 
P = 0.0324. 1 
360 
110 
101 
37 | 
608, observed _ _ _ _ - 
| 1923 
342 
114 
114 j 
38 | 
608, calculated on 9 : 3 :3 :1 basis_ 
X 2 = 2.60. 
P = 0. 4645. 
