No. 610] 



LINKAGE IN LYCOPERSICUM 



611 



Tliese ligures bring out more clearly the fact that the 

 parental combinations axe in excess while the new com- 

 binations are deficient when compared with the theoretical 

 expectations with independent assortment. Combining 

 the numbers of the three types of standard plants and the 

 three of dwarfs brings out another fact, viz.: that the 

 standards exceed the dwarfs far more than is to be ex- 

 pected. This result can not be accounted for on the basis 

 of linkage, because it makes no difference whether habit 

 of vine is or is not linked with any other factor; the ratio 

 of the total number of standards to the total number of 

 dwarfs should approach a ratio of 3:1, if the two char- 

 acters form a simple allelomorphic pair free from any 

 other complicating factors. The same deficiency of dwarfs 

 was noted by these investigators in the other cross re- 

 ported in both the generation and the F3 generation 

 from heterozygous Fo plants. The numbers they ob- 

 tained were as follows : 



stone X Dwarf Aristocrat, F,: Standards ....2,289 2,176 

 Dwarfs 612 725 



