4 BULLETIN 1483, U. S, DEPARTMENT OF AGRICULTURE 
to be superior by individual-tree performance records through sev- 
eral consecutive seasons. This work has been carried on since May, 
1917, in cooperation with the bud department of the Fruit Growers 
Supply Co. of the California Fruit Growers Exchange. About 95 
per cent of the buds of the Valencia orange used by California nurs- 
erymen and growers, a total of 169,499 buds during the calendar 
year 1926, were supplied by that department. 
The production of the orchard trees which have been propagated 
from the selected buds of superior parent trees has been considerably 
larger and the fruit of better commercial quality than from com- 
parable orchards made up of the ordinary mixture of strains. Some 
Valencia orchards which have been unprofitable on account of the 
presence of many trees of inferior strains have been brought into 
profitable production through top-working the trees of the undesir- 
able strains, or replanting them with young trees grown from 
selected buds. 
OCCURRENCE OF UNDESIRABLE VALENCIA VARIATIONS 
The number of trees of the undesirable strains in the orchards 
studied varies so much that it is impossible at this time to make a 
definite statement relative to the frequency of their occurrence. In 
a general way, an average of more than 25 per cent of the trees in 
the orchards under observation have been classified as belonging to 
one or more of the undesirable strains. In some orchards this num- 
ber has been found to be less than 10 per cent, but in others it has 
proved to be more than 50 per cent. 
The trees of several of the least productive and most undesirable 
strains have a very vigorous vegetative habit of growth. They often 
stand out conspicuously in comparison with the neighboring trees 
of the standard strain on account of their large size and dense 
foliage. Trees of some of the undesirable strains have been found 
to develop an excessive number of rank-growing, nonfruiting 
branches commonly called suckers. The use of these suckers as 
sources of bud wood was a common propagation practice prior to 
the time when these bud-selection investigations were begun in 
California. As a result, man}^ buds were generally procured from 
the trees producing the most suckers and relatively few buds were 
obtained from those of the more productive strains, which com- 
monly develop but few, if any, suckers. In this way the suckering 
strains increased in the Valencia orchards to a considerable degree. 
PROGENY TESTS OF LIMB VARIATIONS 
In order to determine whether or not the variations of the Valencia 
orange originating as limb sports may be perpetuated by budding, 
propagations' of a number of limb and individual-tree variations 
which were typical of the most important strains of the Valencia 
variety were made in 1915. The buds from these variations were 
inserted on sour-orange root stocks in a commercial nursery in 
cooperation with the Citrus Experiment Station of the University 
of California, and the resulting progeny trees have been grown on the 
grounds of that station at Riverside. 
