Flower Color in Asy stasia gangetica — Kamemoto and Storey 
67 
TABLE 5 
Segregating Ratios of PB (Purple with Purpleback), Pb (Purple with Non-purpleback), pB (Non- 
Purple with Purpleback), and pb (Non-purple with Non-purpleback from Families 
Heterozygous for P and B in Asystasia gangetica 
PROGENY 
(11 X White) Selfed 
( 7 X 14) Selfed . . . 
OBSE 
RVED 
CALCULATED 
CHI-SQUARE 
PB 
Pb 
P B 
pb 
PB 
Pb 
PB 
pb 
11 
42 
6 
9 
6 
18 
1 
2 
13.5 
40.41 
4.5 
13.56 
4.5 
13.56 
1.5 
4.49 
1.630 
4.490 
Total 
53 
15 
24 
3 
53.46 
17.82 
17.82 
5.94 
4.048 
Chi-square = 7.815 at 5% level. 
TABLE 6 
Segregating Ratios of YB (Yellow with Purpleback), Yb (Yellow with Non-purpleback), 
yB (White with Purpleback), and yb (White with Non-purpleback), from 
Families Heterozygous for Y and B in Asystasia gangetica 
OBSERVED 
CALCULATED 
PROGENY 
CHI-SQUARE 
YB 
Yb 
yB 
yb 
YB 
Yb 
yB 
yb 
(7 X 14) Selfed. . . . 
25 
6 
6 
2 
21.96 
7.32 
7.32 
2.44 
.972 
(7 X 3) Selfed 
33 
13 
15 
4 
36.54 
12.18 
12.18 
4.06 
1.041 
Total 
58 
19 
21 
6 
58.5 
19.5 
19.5 
6.5 
.170 
Chi-square - 7.815 at 5 % level. 
purple pigment in the inner epidermis of 
limb, B, producing purple in the outer epi- 
dermis of limb and back of tube, and Y, 
producing yellow in the entire limb. Each of 
these is inherited in a simple Mendelian fash- 
ion and independently from one another. 
White flowers result only when all three are 
present as homozygous recessives. The inter- 
action of the three genes with one another 
gives rise to the following eight phenotypes, 
when dark purple (PP) and pale purple (Pp) 
are classed together. 
P- Y- B- bronze with purpleback 
P- Y- bb bronze with non-purpleback 
P- yy B- purple with purpleback 
P- yy bb purple with non-purpleback 
pp Y- B- yellow with purpleback 
pp Y- bb yellow with non-purpleback 
pp yy B- white with purpleback 
pp yy bb white with non-purpleback 
A plant heterozygous for P, Y, and B can 
be expected to give rise to a progeny of all 
eight classes in the typical trihybrid ratio of 
27:9:9:3:9:3:3:1. It can be seen that from such 
a progeny, the chance occurrence of a white 
form is only one out of 64 plants. This ex- 
plains the rather limited number of white 
forms appearing among open-pollinated seed- 
lings in nature. Also, if the bronze forms are 
included with purples, the preponderance of 
purple-colored types is to be expected on the 
basis of inheritance of flower color in this 
species. 
The genotypes of the parental plants col- 
lected for this study have been determined as 
follows : 
Plant No. 
1 PP YY bb 
2, 16 PP yy BB 
3,4,5 pp YY bb 
