BUD SELECTION AS RELATED TO QUALITY OP CROP IN 
THE WASHINGTON NAVEL ORANGE 1 
By A. D. Shamel, Physiologist in Charge , C. S. Pomeroy, Pomologist f and 
R. E. Caryl, Assistant Pomologist y Fruit Improvement Investigations , Office 
of Horticultural Investigations , Bureau of Plant Industry , United States De¬ 
partment of Agriculture 
INTRODUCTION 
The occurrence of bud variations in citrus trees and the relation of some of 
them to the origin and development of a number of strikingly diverse strains 
of the commercial citrus varieties grown in California have been presented in 
earlier publications. 2 Evidence that quantity of production may be perpetu¬ 
ated through bud propagation of limb variations of the Washington Navel 
orange has recently been published. 3 Many marked differences in quality of 
fruit, apparently resulting from bud variation, have been under observation 
and several are now being studied in progeny plantings. A variation of fruit 
quality, directly traceable to bud variations in trees of both the Washington and 
Thomson strains of the Washington Navel orange, is herein described. 
FACTORS DETERMINING THE QUALITY OF CROP 
The term “quality of crop” is here used to define the market grade of the 
fruit as affected by its physical characteristics. The size, color, shape, texture, 
and blemishes of the fruit determine its commercial grade in large measure. 
The thickness of the rind, amount and flavor of the juice, character of the rag, 
and the number of seeds are also important physical characteristics of the fruits 
from the commercial standpoint. Fruits of medium size for the variety are 
usually the most valuable, being most desired by the consumer and most profit¬ 
able for the producer. A reddish-orange color is most desirable, while a pale or. 
yellowish color usually lowers the merchandising value of the fruit. In con¬ 
nection with their packing and marketing, uniformity of shape within the va¬ 
riety is an important character. Corrugated, rough fruits or those having an 
uneven surface are usually assorted into lower grades, a skin of uniformly smooth 
texture being most desirable. Blemishes most commonly found are scars, 
scratches, insect injuries, diseased areas, and spots which are apparently due to 
physiological weaknesses of the rinds. 
1 Received for publication January 22, 1924. 
3 The following department bulletins summarize the results of the studies of bud variations in the 
Washington Navel and Valencia orange, Marsh grapefruit, tnd Eureka and Lisbon lemon varieties, 
respectively: 
Shamel, A. D., Scott, L. B., and Pomeroy, C. S. citrus-fruit improvement: a study of bud 
VARIATION IN THE WASHINGTON NAVEL ORANGE. U. S. Dept. AgT. Bui. 623, 146 p., illus. 1918. 
-CITRUS-FRUIT IMPROVEMENT.* A STUDY OF BUD VARIATION IN THE VALENCIA ORANGE. 
U. S. Dept. Agr. Bui. 624, 120 p., illus. 1918. 
-CITRUS-FRUIT IMPROVEMENT: A STUDY OF BUD VARIATION IN THE MARSH GRAPE¬ 
FRUIT. tf. S. Dept. Agr. Bui. 697, 112 p., illus. 1918. 
-CITRUS-FRUIT IMPROVEMENT.* A STUDY OF BUD VARIATION IN THE EUREKA LEMON 
U. S. Dept. Agr. Bui. 813, 88 p., illus. 1920. 
-CITRUS-FRUIT IMPROVEMENT: A STUDY OF BUD VARIATION IN THE LISBON LEMON 
U. S. Dept. Agr. Bui. 815, 70 p., illus. 1920. 
* Shamel, A. D., Pomeroy, C. S., and Caryl, R. E. bud selection as related to quantity 
production in the Washington navel orange. Jour. Agr. Research 26: 319-322, illus. 1923. 
Journal of Agricultural Research, 
Washington, D. C. 
( 521 ) 
Vol. XXVIII, No. 6 
May 10, 1924 
Key No. g-420 
