BREEDING POULTRY FOR EGG PRODUCTION. 



i6i 



This line is shown graphically in Fig. 83, in which the mutant 

 and its progeny are also shown. 



A low line in which no mutant has appeared, but in which 

 also the mean production is not so low as in line D61D168 is 

 D65D366. Since the egg production has not been so low in the 



Pedigree; Line D65D366 



r9F309(OZ))* 

 I 263(4^) 



'$D366(SS)xdD65^ 



^E239{^4-)xd55S 



224(43) Xd 554 

 354{15)xd-551 



r^G 34 U) 

 \ 42 (37) 



ZZ\{31)X$ 552-0 

 344(m^^^^^^ r9F271G?7) 



Mean^^e l¥eanzi3S.4 



362(4-?) 

 L 2l6Ul)xd569] 56 (40) 



I 164 (5) 



rjFsoi (?') 



■i' 223(14) 

 i 221 (4S) 



r 9G 65(^5) 



9F242(J'i) I 209(55) 



22l(S9)xd566-< 267(^5) 



502(S1) 



[ 544 (5) 



Mean^^B.33 



early part of the breeding season with this line it has been easier 

 to propagate it. 



This line is shown graphically in Fig. 82. 



In the examples thus far given we have had to do with pedi- 

 gree lines in which a given degree of fecundity reappeared from 

 generation to generation with practically no change. In two 

 instances quite certainly, and possibly in several others, a new 

 and distinct variation has suddenly appeared within a line and 

 thereafter bred true, thus presenting the characteristic phe- 

 nomena of mutation. The most striking instance of this sort 

 occurred in line D61D168 and may be given here in detail. The 

 main part of this line has already been discussed (p. 160). It 

 will be recalled that it is a line of low fecundity. In 1908 there 

 appeared in it one individual of distinctly higher fecundity than 

 any other bird in the large family of that year. This individual 

 when bred produced only high layers. In the next generation 

 two of these daughters were bred to males known to belong to 

 high fecundity genotypes {$ $ 554 and 566). One of these 

 matings unfortunately produced no adult female offspring. The 



* Bird died during winter period. 



