24 BULLETIN 813, U. S. DEPARTMENT OF AGRICULTURE. 
The performance-record studies reported in this bulletin have been 
carried on during a period when the propagation of lemon trees 
has been particularly active. The lemon industry has expanded 
rapidly during this time, and the information gained in the course of 
these investigations has been utilized generally in the propagation of 
the trees for the large new plantings. A very large number of buds 
from the superior trees of the Eureka strain in the performance-record 
plats have been furnished to propagators. These buds from the 
individual parent trees have been kept separate, so that each progeny 
can be traced at any time from the orchard planting to the parent 
trees. Not only have a great number of buds been taken from the 
best performance-record trees for propagation commercially, but 
buds from some of the poorest trees have also been propagated at the 
same time, in order to compare under orchard conditions the behavior 
of the progenies of the most desirable with those from the undesirable 
parent trees. The active interest shown by lemon growers in these 
studies has given the work an additional interest. 
The early fruiting of the young trees propagated from the select 
trees in the performance-record plats permits comparatively quick 
opportunities for measuring the results of bud selection. The uni- 
formly heavy and superior production of the progenies from the 
desirable parent trees and the light production of inferior fruits of the 
progenies from the undesirable parent trees have demonstrated 
conclusively the importance of bud selection in lemon propagation. 
The information gained from these investigational individual- tree 
performance-record data, the demonstrations of the important 
results of bud selection, and the related observations made during 
the course of these studies have been the basis upon which have been 
developed the present improved methods of practice in California 
in keeping individual-tree records, in the selection of undesirable 
trees in established orchards for top-working or removal, and in the 
choice of superior trees as sources of bud wood for propagation. 
It is desirable to. emphasize the fact that the conclusions presented 
here have not all been derived from a study of the performance-record 
data alone. Some phases of tree and fruit characteristics can not 
be recorded in figures or reproduced by illustrations. These inde- 
finable characteristics are of importance and usually are perceived 
only by those who have a natural aptitude for this kind of work. 
The intimate tree knowledge essential for this work is gained only bj 
almost daily and continuous contact with the trees and fruits. The 
instinct enabling the observer to distinguish one strain of tree or 
fruit from another and to select the best from among many indi- 
viduals is almost, if not equally, as important as the actual tree 
records themselves. 
