162 



BREEDING CROP PLANTS 



with the pink gave carmine and pink in a ratio of 1:1. This 

 indicates that carmine and pink differ in one genetic factor. 

 In a cross of carmine and white the FI was all light carmine. In 

 F 2 there were 54 carmine, 95 light carmine, 26 dark pink, 38 light 

 pink, and 65 white. Some of the extracted whites revealed a 

 tinge of color. Crosses of extracted whites with pink gave 32 

 carmine and 62 pink, showing that extracted whites sometimes 

 carried a carmine factor. The factor relations are not entirely 

 clear. 



Quantitative Characters. Many of the so-called size charac- 

 ters of tobacco are of great commercial importance. For this rea- 

 son their mode of inheritance is of much interest to the breeder. 

 Extensive studies of inheritance of these size characters have 

 been made. Inheritance of leaf number will be given as an 

 example of a common type of inheritance of size characters in 

 this group. Sumatra, which averages 27 leaves, was crossed with 

 Broadleaf, which gives an average of 19.4 leaves. The results 

 for the parents and FI to F 3 generations as obtained at the Con- 

 necticut Station are given in Table XXXVII (Hayes, East, and 

 Beinhart, 1913). 



TABLE XXXVII. INHERITANCE OF LEAF NUMBER IN CROSS (403 X 401) 

 SUMATRA X BROADLEAF 



