MAINE AGRICULTURAL EXPERIMENT STATION. 



I9II. 



and showing the occurrence of high and low fecundity lines. 



As a typical example of a high fecundity pedigree line in 

 which the high fecundity is genotypic, line D5D39 may be con- 

 sidered. In the presentation of this and other pedigree tables 

 the following conventions are adopted. The band numbers of 

 the birds are in bold-faced type, and following the band num- 

 ber of each female, her winter egg record is given in italic fig- 

 ures enclosed in parenthesis. The band numbers of males are 

 given in italics. 



This line is shown graphically in Fig. 81. 



Little comment on this pedigree line is necessary. We see a 

 certain high degree of fecundity faithfully rej)roduced genera- 

 tion after generation. Different males were used with different 

 females, but in every case the males used were from high 

 fecundity lines and were believed to carry this quality in their 

 germ cells either in homozygote or heterozygote condition. 



In marked contrast to the last example let us consider the low 

 fecundity lines D61D168. It is a troublesome matter to propa- 

 gate the low fecundity lines, because of the difficulty of getting 

 a sufficient number of eggs during the early part of the breed- 

 ing season. The line D61D168 is of interest not alone as an 

 illustration of a typical low line, but also because there appeared 

 in it a mutation, or something very like one. We will consider 

 here only the main line and not the mutant. 



Pedigrei; Line D61D168 



'$Dl68{33)x$D61- 



9E231 {:i'5)x$55S 



419 {9)x$551 



209 (S8)x$ 555—0 

 313 {B6)x$554 



363 {ll)x$550 

 15 {18) 



163 (P) 



200 {W) 



141 (0) 



116 (J'S) 



151 {11) 

 24 {SS) 

 ]\leanz::17.5 

 9E248 (48)* 



9F233{SS)x$57. 

 '$F16S(7)x$569 



174(,g'Z) 

 9F249(S0) 



-0 



9G221(i(5) 

 430(1^) 

 477 1 

 ^fcanz^.67 



* This was the mutant referred to. Its progeny will be considered 

 later. See p. 161. 



