\ 
Ernest Warren 
113 
and the offspring were all pale-coloured; but when the intensity was decreased by 
selection to about 4, the " white " plants showed Mendelian segregation, for the 
offspring arising from the plants produced from a cross with a dark-coloured 
plant were sharply divisible into strongly coloured and " white " individuals. 
As a further example of selection, I started with a homozygous medium- 
coloured (48) plant (G). This was selfed and a family of 31 coloured plants was 
raised, there were no whites. Thus, the parent plant may be regarded as homo- 
zygous. A plant ((? 3) in this family, not far removed in colour (55) from the 
average, was selfed and the resulting family had a mean coloiir approximating to 
the colour of the parent. A light-coloured (27) plant {G 3, 20) and a dark (81) 
plant (G 3, 13) in this last family were selfed also, and the two families raised 
tended to resemble their respective parents. In a succeeding generation further 
progress was obtained in securing a dark race and a pale race. The necessary 
details are given in the accompanying diagrammatic table. The families printed 
in heavy type are those leading to a dark race, while those in ordinarj' type are 
passing into a light race. 
Formation of Light and Dark Races from a Dominant 
(homozygous) G. 
Parents 
Number 
G (selfed) 
0 pi. 3 
a .3, pi. 20 
a 3, pi. 13 
G 3, pi. 20 
G 3, 13, pi. 
Colour 
k8 
r>5 
38 
81 
27 
80 
Offspring — Scale of Colour 
Oo 
l1 
1 
C;. 
in 
1 
1 
03 
1 
1^ 
1 
-fc- 
1 
*~ 
1 
-t. 
1 
9 
15 
6 
2 
1 
0 
4 
4 
3 
1 
I 
2 
3 
2 
2 
2 
3 
4 
.5 
2 
2 
6 
2 
Correlation Table — Colour -Intensity — Dominants {homozygous). 
Series II and III. 
Parents. 
Grade of 
Colour- 
Intensity 
>~4 
1 
1-.* 
'o 
f 
f 
r 
5S 
? 
T 
L_L. 
f 
O 
1 
(0 
f 
O 
ur 
K 
30— 39 
1 
4 
9 
3 
17 
40— 49 
2 
7 
26 
29 
10 
74 
50— 59 
4 
31 
38 
23 
4 
100 
GO— 00 
3 
18 
37 
31 
13 
1 
103 
70— 7,9 
2 
2 
8 
19 
54 
50 
9 
0 
1 
145 
80— 89 
2 
5 
4 
3 
2 
1 
17 
90— 99 
2 
5 
9 
7 
\b 
8 
5 
5 
5 
61 
100—109 
0 
110—119 
2 
0 
1 
3 
120—lf29 
1 
5 
2 
1 
9 
Totals 
2 
5 
11 
13 
28 
36 
91 
134 
112 
G9 
25 
3 
529 
Bioiuetiika xiv 
8 
