8 BULLETIN 803, U. S. DEPARTMENT OF AGRICULTURE. 



PLAN OF INVESTIGATION. 



As it does not appear that any systematic study has been made of 

 the ripening of olives in California, the plan of this investigation was 

 first to follow the development of the fruit on marked trees, record- 

 ing changes of composition and physical characteristics, especially 

 color, in order to establish, if possible, the differences between im- 

 mature and ripe fruit, and to ascertain how closely the color of the 

 fresh fruit is related to or may indicate maturity. This was done for 

 different varieties and localities, and during successive seasons to 

 show the influence of these factors. In the second place, to make the 

 data applicable to the finished product, different lots of olives were 

 followed through the pickling process to find what changes occur in 

 the composition and color. 



FIELD WORK ON FRESH FRUIT. 



When the field work was taken up in 1914, the season was too far 

 advanced to permit of any investigation of composition changes 

 during growth. However, in the middle of December, when the 

 fruit certainly could be considered mature in almost all localities and 

 a large part of the picking was completed, series of samples of the 

 most important varieties of olives were collected from the same or 

 neighboring trees in localities in the northern and southern districts. 

 They were analyzed both to afford data on mature fruit and to show, 

 if possible, the relatiofi of color to composition. Also a number of 

 pickling factories were inspected, and men prominent in the industry 

 interviewed. 



In the 1915 season the systematic study of the ripening was under- 

 taken in the northern district. Trees of different varieties in different 

 localities were marked and sampled at intervals of practically three 

 weeks from September 15, when the fruit is well formed, to Decem- 

 ber 15. Since fresh olives are worth from 15 to 20 cents a pound, the 

 value of one tree's crop is so great that no attempt was made to buy 

 outright the whole crop of the trees under observation. As it was 

 considered desirable to follow the development past the regular har- 

 vest time, arrangements were made with the growers to leave a certain 

 portion of the tree untouched in the picking. Unfortunately, the 

 picking is done by Japanese, Hindus, and Mexicans, and, ia spite of 

 the owners' efforts, many of the trees had been nearly stripped, or at 

 least most of the highly colored fruit had been picked, at the last 

 sampling period. In the northern district the grower generally as- 

 sumes the frost risk up to December 10, and most of the picking is 

 over by the middle of that month. 



The plan of operations for the 1916 season was the same as for that 

 of 1915, except that the trees were more numerous and were scat- 

 tered over all the important olive districts. 



