INHERITANCE OF EGG CHARACTERS 25 



Twenty-nine dams in the lowest pigmented class, pale pinkish buff, had 160 

 daughters. About one daughter laid white eggs to five laying tinted eggs. 

 Among those laying tinted eggs, the prevailing shade was pale pinkish buff, 

 but a greater proportion showed intermediate shades than in the preceding 

 group. 



The next deeper pigmented class of dams was the pale pinkish cinnamon 

 group. This class of dams gave white to pigmented daughters in the pro- 

 portion of one white to 8 pigmented. No dams of this class belonged to line 

 C, but lines A and B behaved in the same general way. A significantly great- 

 er proportion of daughters of this group fell into the deeper pigmented classes. 



The pale cinnamon pink class is next in amount of pigmentation. Six dams 

 produced 69 daughters. Only one of this number laid white-shelled eggs, about 

 one-third laid lightly pigmented eggs, and fully one-half laid deeply pigmented 

 eggs. 



The moderately deep pigmented class, light pinkish cinnamon, was repre- 

 sented by 14 dams and 143 daughters. Only four daughters produced white 

 eggs, and 34 of the daughters showed deeper shell pigmentation than their 

 dams. This fact affords good evidence that shell pigmentation depends on 

 multiple factors and that several factors accumulate to produce deeper shell 

 pigments. 



Light vinaceous cinnamon represents the most deeply pigmented class of 

 dams. Eight dams produced 55 daughters. There was still a small number of 

 white shell daughters, but about half the daughters belonged to the deeply 

 pigmented classes. 



The question arises at this point as to what is the typical shade of shell 

 color in the Rhode Island Reds used in this experiment. It is further important 

 to know whether the typical color is the most desirable color and to secure as 

 much information as possible on how to produce a population uniform for the 

 shade desired. 



The totals at the bottom of table 11 are of interest in this connection. The 

 most common single color is pale pinkish buff which represents a low degree 

 of pigmentation and is too light in shade to be desirable. The light pink cinna- 

 mon shade prevails in the daughters that laid eggs with more deeply pigmented 

 shells, and the light vinaceous cinnamon shade appeared in large numbers. It 

 is probably justifiable to assume that a shell color approaching light pinkish 

 cinnamon or light vinaceous cinnamon is most desirable in Rhode Island Reds. 

 As already pointed out, dams belonging to either of these two classes gave very 

 few daughters which laid eggs of the lighter shades. These facts indicate that 

 two or more cumulative genes are necessary to produce the deeper pigmented 

 shades. Crosses between light and dark shell types might be expected to give 

 blending, and dark shell birds would give a range in color shades of daughters 

 unless the dams and sires were homozygous for the pigment genes concerned. 

 Egg shell color can be intensified by selection for breeding females laying 

 deeply pigmented eggs and males that carry a similar inheritance. In this way, 

 after a few generations the flock should show uniformity in egg color of the 

 desired shade and freedom from white or lightly pigmented eggs. 



