UNITED STATES DEPARTMENT OF AGRICULTURE 





I BULLETIN No. 697 



Contribution from the Bureau of Plant Industry 

 WM. A. TAYLOR, Chief 





Washington, D. C. 



September 27, 1918 



CITRUS-FRUIT IMPROVEMENT: A STUDY OF BUD 

 VARIATION IN THE MARSH GRAPEFRUIT.^ 



By A. D. Shamel, Physiologist in Charge, L. B. Scott, Pomologist, and C. S. Pom- 

 EROT, Assistant Pomologist, Fruit-Improvement Investigations, Office of Horticultural 

 and Pomological Investigations. 



CONTENTS. 



Introduetion 



History of the variety 



Variability within the variety 



Objects of the investigations 



Plan of the investigations 



Methods of keeping performance records . 



Tree numbers 



Picking 



Assorting 



Recording 



Descriptions of important strains 



Marsh strain 



Seedy strains 



Rough strain 



Page. 

 Descriptions of important strains— Continued. 



Bell strain 17 



Alternate-Bearing strain 17 



Unproductive strain 17 



Infrequent fruit variations. 18 



Seasonal fluctuations in production 19 



Presentation of data 20 



Comparative value of the strains 106 



The unintentional propagation of undesirable 



strains 108 



The isolation of strains through bud selection. 109 



Top- working undesirable trees 110 



The selection of bud wood HI 



Summary 112 



INTRODUCTION. 



The commercial production of grapefruit (Citrus grandis Osbeck) 

 in California began about 1890. Previous to this time^ bearing 

 grapefruit trees of many varieties were to be found in some citrus 

 orchards, but the crops from these trees were largely used for home 

 consumption or were sold in local markets. Most of the early 

 plantings were of Florida-grown trees and of varieties many of which 

 proved to be undesirable for California conditions. The fruits usu- 

 ally contained a large number of seeds and were inferior in size, shape, 

 texture, flavor, or other important commercial characteristics. 



1 This is the third in a series of pubhcations summarizing the citrus fruit-improvement investigations 

 of the United States Department of Agriculture. The two previous reports were presented in Department 

 Bulletins Nos. 623 and 624, treating of the work with the Washington Navel orange and the Valencia 

 orange, respectively. 



56085°— 18— Bull. 697- 



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