74 Studies of Inheritance in the Japanese Convolvulus 



(/) W.® l^^ve 342 plants with red and 127 with white flowers, thus 

 their ratio is 3:1, the deviation and the standard error being + 9-750 

 -and ± 9-377, respectively. 



(g) All breed true to red flowers. 



Qi) All breed true to white flowers. 



As will be seen from above, there are some cases where the deviation 

 is larger than the standard error, but these differences are not very large, 

 and it may be safely concluded that the results of all these experiments 

 ^re in accordance with expectation. Furthermore, from the results of 

 jPg and F^ we may deduce the following facts : 



1. No homozygous green plants with red flowers were found. 



2. In the offspring derived from green plants with red flowers leaf- 

 ■colour always segregates into green and yellow, while the segregation 

 of flower-colour is either exactly similar to that in F^, or different from 

 it, in so far as no white flowers are produced. 



{e) Back-crossing and F^. 



In 1916 the back-crossing of one .^i plant {— A x B) by both of 

 the two parents was done. 



The results of Fj x A are indicated in Table XXI. 



Totals ... 78 86 164 



In this case the flower was either white or magenta as in Fj , and all 

 coloured flowers were white-margined. 



From the results in F2 it may be a priori expected that the ratios of 

 green and yellow plants, and that of red and white flowers, are 1 : 1 

 respectively. Indeed we have obtained 81 green and 83 yellow plants, 

 thus our expectation was so perfectly fulfilled that no further com- 

 ment is necessary. The ratio of plants with red and white flowers is 

 ■equally 3:1, the deviation and the standard error being ± 4-000 and 

 X 6-043, respectively. 



The results of back-cross F^x B are shewn in Table XXII. 



In this case we should expect from the results of F2 that leaf-colour 

 would remain constantly green, that the ratio of plants with white- 

 margined and fully-coloured flowers would be 1:1, and finally that the 



