CHARACTERS IX AX UPLAND-EGYPTIAN COTTON HYBRID. 
23 
Table 5. — Fy frequency distribution for the character petal spot in Holdon* 
rot ton hybrids. 
Grade numbers. 
2 3 4 5 
6 
2 6 5 8 
3 
SO 
<?o 
/o 
o 
S <*■ S G- r <3 S 
tf 
%~ 
eo 
SO 
<eo 
SO 
^o 
/o 
o 
/ *? 
s 
-?■ S 6 7 <3 & 
to 
y 
^ 
/ 
y y 
^ 
A 
p y 
V 
f 
jN. 
/» (/VO JO9#/s?T/0mJ 
//' 
Fig. 31.— Stigma index: Frequency distribution 
of Holdon X Pima Fc cotton plants, by grades, 
as used in computing the correlations. The 
ordinate figures indicate the number of plants 
as a percentage of the total Tjopulation. 
Fig. 32.— Boll lock number: Frequent 
bution of Holdon X Pima F* cotton" plants. 
by grades, as used in computing the correla- 
tion-. The ordinate figures indicate the 
number of plants as a percentage of the total 
population. 
It would seem that while the presence of the spot is dominant over 
complete absence, the magnitude of its development when present is 
conditioned by modifying factors. Further data on the segregation 
in respect to this character were obtained in F 3 . 
Progenies were grown in 1920 from 22 F 2 individuals selected in 
1919, of which 4 had been graded as lacking the petal spot while the 
others showed its presence in varying degree, from grade 1 to grade 7. 
eo 
so 
*o 
so 
20 
/o 
o 
7 <5 S> 
/.USl 
1 
^p 
y 
/ 
r 
^4. 
/° 
/ 
r 
i 
> 
/ 
\ 
^ 
/ 
^**% 
\ 
k 
//- 
Fig. 33.— Boll length: Frequency distribution of 
Holdon X Pima F; cotton plants, by grades, 
as used in computing the correlations. The 
ordinate figures indicate the number of plants 
as a percentage of the total population. 
so 
+0 
JO 
20 
H* 
1 
/ 
V 
lJ 
-// 
Fig. 34.— Boll diameter: Frequency distribution 
of Holdon x Pima Fj cotton plants, by grades, 
ised in computing the correlations. The 
ordinate figures indicate the number of plants 
as a percentage of the total population. 
All points on the F 2 frequency distribution for this character 
were represented by one or more of the parents of F.. progenies. Table 
6 gives the frequency distributions for petal spot of the parental and 
F 2 ' populations of 1919 and of the F 3 progenies of 1920, the latter 
being arranged in the order of the grade value for this character of 
the respective F 2 parent, as shown in column 4. 
