CONTENTS. 7 



Department Bulletin No. 623. — Citrus-fruit Improvement: A Study of 



Bun Variation in the Washington Navel Orange: Page. 



. Introduction 1 



History of the Washington navel variety 2 



Variability within the variety 3 



Occurrence and frequency of bud variations 5 



Objects of the investigations 7 



Plan of the investigations 7 



Methods of keeping performance records 9 



Descriptions of some of the important strains 14 



Individual fruit variations 24 



Minor variations of fruits 27 



Lessons taught by these investigations 27 



Presentation of data 29 



Comparative value of the strains 140 



The unintentional propagation of undesirable strains 141 



The isolation of strains through bud selection 142 



Top-working undesirable trees 144 



Summary 145 



Department Bulletin No. 624. — Citrus-fruit Improvement: A Study 

 of Bud Variation in the Valencia Orange: 



California citrus varieties 1 



History of the Valencia variety 2 



Variability within the variety 3 



Occurrence and frequency of bud variations 4 



Objects of the investigations 5 



Plan of the investigations 6 



Methods of keeping performance records 7 



Descriptions of some of the important strains 8 



Individual variations of fruits 12 



Minor variations of fruits 13 



Lessons taught by these investigations 13 



Presentation of data 14 



Comparative value of the strains 114 



The unintentional propagation of undesirable strains 115 



The isolation of strains through bud selection 116 



Top-working undesirable trees 118 



Summary 119 



Department Bulletin No. 625. — Cropping Systems for the Moister Por- 

 tion of Eastern Washington and Oregon and Northern Idaho: 



Clover in the rotation to eliminate summer fallow 1 



Factors influencing farm profits 2 



Methods of increasing farm profits 4 



Seeding clover with a nurse crop 6 



Rotation for increasing profits 9 



