834 
Journal of Agricultural Research 
Vol. XXIV, No. lo 
Table XIV .—Relation of Xo(f and Yy in F2 generation of cross MummyXGradus 
rogue (YYVY X data from Table XIII. 
XY or Xy 
rogues. 
x'Y or x'y nonrogues. 
i Total. 
i 
Interme¬ 
diate. 
Broads. 
Observed, 12:3:1 ratio. 
182 
77.12 
75.00 
2.12 
46 
19.49 
18.75 
•74 
8 
3-39 
6.25 i 
2.86 1 
i 
j 
i 
236 
Percentage found. 
Percentage expected. 
Difference (D). 
x “=2.8 s 87 
P=.223I 
Observed, 3:1 ratio. 
182 
77.12 
75.00 
2.12 
1.89 
I. 12 
54 
22.88 
25.00 
2.12 
i 
236 
Percentage found. 
j 
Percentage expected. 
! 
Difference (D). 
i 
Standard error (S. E.). 
D/S. E. 
.. 
i 
The presence of the broads in the Fj generation of the cross Gradus 
rogue with Mummy is accounted for by assuming the presence of two 
factors y and x for stipule width in Gradus, factor y being allelomorphic 
to Y in Mummy and factor x allelomorphic to x' found in Mummy. 
Ordinarily neither x nor x' has any visible effect on stipule shape in 
either variety. Occasionally the factor x in Gradus mutates to X, 
which has for its somatic expression a mean stipule ratio of about 2.35. 
Factor X interacts with its allelomorph x as found in Gradus and is 
dominant to x' of Mummy. It also masks either member of the factor 
pair Yy. Any Fj segregate that is heterozygous or homozygous for 
the factor X has rogue stipules, irrespective of whether Y or y is present. 
An individual in which X is absent has intermediate or broad stipules, 
depending on the presence or absence, respectively, of the factor Y. 
In the Fj generation the plants segregate into approximately 12 rogues; 
3 intermediates; i broad, according to the following scheme: 
5 ..Gradus rogue, XXvyXMummy, XX x' x' 
F..Rogue, Xx'Yy 
^2. Rogues: Intermediates: Broads: 
Xy Xy x^Y x^y 
Percentage.56.25 18.75 18.75 6.2s 
Ratio. 12 ; 3 j ^ 
Rogues (X): Non-rogues CXf) : 
Ratio. 3 . 
Rogues and Intermediates: Broads: 
Returning again to the results tabulated in Table XIV, the observed 
number in any one category of plants is expressed in percentages of the 
total number of plants classified. For the rogues, intermediates, and 
types the percentages are 77.12, 19.49, and 3.39, respectively, compared 
with the theoretically expected 75.00, 18.75, and 6.25 for the respective 
classes, the deviations of the observed percentages from the calculated 
are not statistically significant (P having a value of 0.2331). The 
greatest deviation is caused by the exceptionally low number of board- 
stipuled plants found. The deficiency in the broad class, however. 
