CROSSING PRODUCTION AND EXHIBITION BIRDS 7 



Table 3. --Distribution of Offspring with Respect to Surface Plumage 



Color. 1930-1933. 



The exhibition stock of both sexes was described as about 70 per cent standard 

 in color with about 30 per cent dark or medium. The production stock showed 

 no standard-colored birds, very few dark, with the great majority medium or 

 light in color. 



Reciprocal crosses to produce the Fi generation gave significantly different 

 results with respect to plumage color of male offspring but not of female offspring. 

 Male offspring produced by mating exhibition males to production females were 

 significantly darker in surface color than those from production males mated to 

 exhibition females. In Table 2 the female offspring from the second type of 

 mating showed a greater proportion of early maturing offspring than the first. 

 It is probable also that the male progeny of this second type of mating were 

 somewhat earlier maturing than those from the first type of mating. Since the 

 lighter shades of red are more likely to occur in males than in females (Hays, 

 1932), it is probable that the males from the second type of mating were lighter 

 because of physiological relations between sexual maturity and plumage color. 



F2 generation males on the average were slightly lighter in plumage color than 

 either type of Fi males. The segregation observed in this generation was not 

 marked and this would indicate that neither parental type was homozygous for 

 the factors affecting plumage color. This fact also accounts for the wide range 

 in plumage color observed in the Fi generation and renders difficult the establish- 

 ment of uniform color by crossing exhibition and production birds. Fo females 

 showed about the same range in surface color as Fi females. 



In matings 4 and 5 the character of progeny from reciprocal crosses of Fi 

 hybrids on parental stocks is shown. Both sexes were lighter in color when the 

 sire was of pure production ancestry. This fact suggests possible dominant 

 sex-linked modifiers for lighter shades of plumage. 



