F eb. 16, 1924 
Inheritance of Petal Spot in Pima Cotton 
495 
THE SECOND GENERATION OF THE CROSSES 
Table III gives the frequency distributions and Table IV the statistical 
constants of the parental and F 2 hybrid populations grown in 1922. 
Because of the pronounced segregation in the F 3 progenies, the means and 
standard deviations were computed separately for the spotted and the 
spotless class in each progeny. 
Table III. —Frequency distributions for petal spot grade of the parental and F 2 
progenies grown in 1922 
Population. 
PARENTAL 
12-13 (spotted). 
1-3-12-14-2 (spotless). 
HYBRID (F 2 ) 
(1-3-I2-I4X12) 20. 
(I-3-I2-I4XI2) 28 
parental 
13-8 (spotted). 
3-2-4-1-22 (spotless) 
HYBRID (Fo) 
( 3 - 2 - 4 - 1 X 13 ) 21. 
( 3 - 2 - 4 - 1 X 13 ) 24 
Petal spot grade (plant averages). 
Number |_ 
of plants. | ! | ' 
4 F 3 progenies as one array.. 
o j0.5ii.0 ( i.5ia.0ja.5]3.03.514.0 
26' 
29 ! I i I 5 ! I 3 ! 
28 
33 
28 
47 
179 
4110 
1; 8 
! ! 1 
2! 
! ! ; 
51 il.. Uf. 
20! 12 i 
21 2 
6| 3 
4* *5 5*° 5-5.6.0 
6-5 
7.0 
7.518.0 
8.5 
i 3 
! 
2612 
1 ! 
.! I 1 
j;.. 
2 5 
12 
21 141 9 | I 
I ! 
I 
39 
5; 12 
m . 
2 3 
3 i 
10 
16 
Table IV. —Statistical constants for petal spot grade of the parental and F 2 progenies 
grown in 1922 , the constants being given separately for the spotted and the spotless 
segregates of each hybrid progeny 
Population. 
PARENTAL 
12-13. 
I-3-12-14-2. 
HYBRID (Fo) 
(l-3-I2-I4Xl2) 20. 
Do. 
(1-3-12-14X12) 28. 
Do. 
PARENTAL 
* 3-8 . 
3-3-4-1-22. 
HYBRID (F 2 ) 
(3-2-4-IXI3) 21. 
Do. 
(3-2-4-1x13) 24. 
Do. 
Class. * 
Number of 
plants. 
Mean. 
Standard 
deviation. 
Spotted. 
26 
7.7 ±.04 
0-34 
Spotless. 
29 
. 7 ± . 04 
.28 
Spotted. 
31 
6.7± .08 
•63 
Spotless. 
16 
• 4 ± .05 
•30 
Spotted. 
42 
7 .o±.o 7 
.69 
Spotless. 
15 
. 7 =b. 06 
•36 
Spotted. 
28 
7-6± .05 
•39 
Spotless. 
33 
• 7 i • °3 
.27 
Spotted. 
21 
6.9±. 10 
.68 
Spotless. 
7 
• 6rt. 13 
•52 
Spotted. 
36 
7 • 1 dt. 09 
.83 
Spotless. 
11 
• 7 dr . 08 
•39 
