10 BULLETIN 697, U. S. DEPARTMENT OF AGRICULTURE. 
raent : How to Secure and Use Tree-Performance Records." In order 
to make the present discussion complete, the following brief resume 
of the methods used for obtaining the grapefruit performance-record 
data is here given. 
TEEE NUMBERS. 
The performance-record trees have been given individual-tree 
numbers, consisting of the number of the block, the number of the 
row, and the position of the tree in the row, counting always from 
some fixed point, as, for example, the irrigation head. This number 
is painted on the tree trunks, always in the same relative position, 
with white-lead paint. The figures are made large and plain and 
are so placed as to be easily legible and accessible. 
PICKING. 
The trees are picked by trained pickers from the regular crews 
employed on the properties where the plats are located. Usually 
the same men have picked the performance-record plats every 
season. In this work all of the fruits of each tree have been picked 
at one time. Owing to the fact that the eastern market season for 
California grapefruit is best in midsummer, a condition which has 
been recognized fully only recently by the California growers, the 
time of picking the performance-record plats has been postponed 
each year, until at the present time it begins during the latter part 
of June. 
The fruits from the trees in the performance-record plats are, of 
necessity, handled more often than is ordinarily the case. For this 
reason, especial care has been used in handling, in order to avoid so 
far as possible all mechanical injuries to the fruits. After the per- 
formance-record observations have been completed, the crop of each 
tree, except such samples as may be required for further study, is 
included in the general field crop and sent to the packing house. 
ASSORTING. 
The fruits from the individual trees are assorted into three grades, 
viz, Ivory- White, Standard, and Cull. The Ivory- White or commercial 
grade corresponds to a first and the Standard to a second grade. 
The Ivory- White grade includes all of the .most valuable commercial 
fruits; the Standard, all of the blemished fruits, or those having poor 
color, shape, or other inferior commercial characteristics, but suitable 
for shipment to market; and the Cull grade, those fruits which for any 
reason are not worthy of packing for the market. 
The work of assorting grapefruits according to size and grade has, 
of necessity, been done by hand, as shown in Plate IV. No machines 
such as are used with other citrus fruits are available for sizing Marsh 
grapefruits satisfactorily for these investigations. In the perform- 
