114 
S. IKENO : 
From the results given in the Table VII, A we expect to have 1 
CCRRBB, 2 CCRrBb and 1 CCrrbb in the ^-generation. In the 
Table VII, B showing the Fl-ofispring we have the IVparents of magenta 
colour, No. 1-23. Of these No. 1 has produced only 1 magenta plant 
and is not entered in the total, because it indicates naturally nothing for our 
experiment. Nos. 2-4 belong to CCHUBB, and Nos. 5-23 to CCRvBb 
whilst each of 12 oranges belongs to CCrrbb, because it has produced, 
nothing but oranges. We have thus 3 CCRRBB: 19 CCRrBb: 
12 CCrrbb, theoretically 8 - 5 :17-0 : 8*5. Of the heterozygous magentas 
CCRrBb (i. e. Nos. 5-23) each of Nos. 5-12 has segregated into magentas 
and oranges, just as did the I^-hybrid in F 2 , their approximate ratio being 
3:1 in total, and evidently this is so, because in these magentas the factors 
R and B remain in absolute linkage. On the contrary, in each of magentas, 
Nos. 13-23, we observe the appearance of the reds, and this is clearly due 
to the breaking down of the complete linkage between these factors. Since 
we have in all 181 magentas, 20 reds and 64 oranges, i.e. 7 ‘6% reds, there 
are too few reds to consider that the free assortment has taken place between 
R and B, because we should have in the latter case nearly 149 magentas, 
50 reds and 66 oranges (9 : 3 :4), i.e. 18 ‘9% reds. It is quite evident that 
in our present case the linkage has been changed from complete to partial, or 
at least has changed its intensity from very high to low. What is then the 
ratio of “ coupling ” or “ linkage ” in the latter case ? For its determination 
the following calculations were made :— 
Magenta 
Red 
Orange 
Totals 
Actual . 
{cub) 
181 
178-5+7-6 
181-2±7-6 
( Clib ) 
20 
20 2+4-5 
17-6+4-2 
{CrB+ Crb) 
64 
66-2±71 
66-2±7-0 
265 
265 on 5 :1:1:5 basis 
265 „ 6:1:1:6 „ 
Expected . 
If we calculate the closeness of fit by the method of Pearson we find for the 
first and the second case y- = 01099 and 0’4006 respectively, each of which 
should indicate an almost perfect agreement of the actual number with the 
