2 BULLETIN 1073, U. S. DEPARTMENT OE AGRICULTURE. 
that the trees are budded over to more promising varieties. At the 
1920 spring meeting of the California Avocado Association more than 
60 varieties of avocados were on exhibition. In a wise attempt to 
restrain the commercial plantings of new varieties or strains which 
have not been thoroughly tested, the association maintains a list of 
those recommended for commercial use. The varieties now listed 
are Dickinson, Fuerte, Puebla, Sharpless, and Spinks. Blakeman, 
Lyon, and Taft, listed in 1919, have been dropped. Descriptions of 
these varieties can be found in the annual report of the California 
Avocado Association for 1917 and in the Manual of Tropical and 
Subtropical Fruits, by Wilson Popenoe. 
PURPOSE OF INVESTIGATION. 
When it is desirable to harvest fruits or vegetables before they 
mature,, the problem of determining the time of their optimum 
condition is seldom an easy one. It is particularly difficult in the 
case of fruits that are raised at a great distance from their markets, 
in which class belong practically all Pacific coast fruits. Much 
difficulty has been experienced in trying to place these fruits in eastern 
markets in a state satisfactory to the consumer, the tendency being to 
harvest the fruit before it is ready, which results in putting a poor 
and flavorless product in the hands of the consumer. 
While it is true that the avocado has not yet reached the stage of 
development where it is being shipped to eastern markets in commer- 
cial quantities, that time is fast approaching, and even now, under the 
commercial methods of marketing it in California, knowledge of its 
composition at maturity is imperative. Avocados are harvested 
while hard and kept in storage at hotels, clubs, or markets until they 
have softened. If picked too early the fruit has a tendency to 
shrivel and become "rubbery," is watery, and lacks the characteristic 
flavor of well-matured fruit. Its maturity problem thus assumes 
special importance. Furthermore, this fruit is now in the first 
period of its development, as far as the American market is concerned. 
False impressions of its quality created at this time may greatly 
injure its future. Already some adverse criticism of the avocado, 
usually traceable to those who have bought immature fruits, is 
encountered. 
The composition of fruit of all of the varieties now grown and of 
that from seedling trees brought into bearing each year, therefore, is 
a matter of no little interest to the avocado grower. The work here 
reported was undertaken for the purpose of throwing some light 
upon the problems just enumerated. 
