AUTHOR S ABSTRACT OF THIS PAPER ISSUED 

 BY THE BIBLIOGR.^JHIC SERVICE, FEBRUARY 24 



THE BEARING OF RATIOS ON THEORIES OF THE 

 INHERITANCE OF WINTER EGG PRODUCTION 



H. D. GOOD ALE AND GRACE MACMULLEN 



Massachusetts Agricultural Experiment Station 



CONTENTS 



Introduction 83 



The problem 83 



An alternative theory 85 



The material and its treatment ; 88 



The kind and sources of data used 88 



The arrangement of data 88 



The position of the numerical division point between high and mediocre 



producers 89 



Data on Barred Plymouth Rocks, Cornish, and reciprocal crosses 90 



Data on Rhode Island Reds and Cornish 91 



General 91 



The progeny of Rhode Island Red male no. 3003 92 



Cornish male by Rhode Island Red female cross 109 



Bearing of modifications in management on the results 112 



Size of families 113 



Ratios among the parents needed to give the observed mean winter egg pro- 

 duction of American breeds with random matings 116 



Critical value of males of classes I, II and V for Pearl's theory 116 



Summary of criticisms of both theories 118 



Conclusions 118 



Summary 119 



Literature cited 120 



Appendix 1. Changes in methods of management 121 



Appendix 2. Statement to practical poultrymen 123 



INTRODUCTION 



The problem 



We owe to Pearl ('12) the first Mendelian theory appHcable 

 to the inheritance of fecundity. This theory may be stated as 

 follows. The winter egg production of the pullet year, i.e., the 

 eggs laid before March 1, is a good index of annual production. 

 Production during this period falls into three classes, viz., high 



83 



