UNITED STATES DEPARTMENT OF AGRICULTURE 
IMI BULLETIN No. 697 
sSt^*9Ko? Contribution from the Bureau of Plant Industry 
^m&*4ff*?T WM. A. TAYLOR, Chief 
sur^pmru 
s&&yfrJL 
Washington, D. C. 
September 27, 1918 
CITRUS-FRUIT IMPROVEMENT: A STUDY OF BUD 
VARIATION IN THE MARSH GRAPEFRUIT. 1 
By A. D. Shamel, Physiologist in Charge, L. B. Scott, Pomologist, and C. S. Pom- 
eroy, Assistant Pomologist, Fruit-Improvement Investigations, Office of Horticultural 
and Pomological Investigations. 
CONTENTS. 
Introduction 1 
History of the variety 4 
Variability within the variety 5 
Objects of the investigations 8 
Plan of the investigations 9 
Methods of keeping performance records 9 
Tree numbers 10 
Picking 10 
Assorting 10 
Recording 11 
Descriptions of important strains 12 
Marsh strain 13 
Seedy strains 14 
Rough strain 16 
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 Ill 
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. 
i This is the third in a series of publications 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- 
