BUD VARIATION IN THE WASHINGTON NAVEL OEANGE. 7 



. Tree-census observations in navel-orange orchards in California 

 show a general average of about 25 per cent of trees of diverse strains, 

 most of which are inferior to the Washington as regards both the 

 amount and the commercial quality of the fruit. As a rule, the 

 younger orchards show a larger proportion of trees bearing inferior 

 fruits than the older orchards. This condition indicates that the 

 prevailing methods used for the propagation of the Washington 

 Navel orange variety are causing the deterioration or "running 

 out" of the variety as a whole through the perpetuation of an in- 

 creasingly large proportion of undesirables 



OBJECTS OF THE INVESTIGATIONS. 



The objects of these investigations are (1) to ascertain the varia- 

 tion which has taken place in the Washington Navel orange through 

 bud variation; (2) to determine the extent to which undesirable 

 variations have been propagated, as shown by the percentage of such 

 undesirable trees existing in the present bearing groves; and (3) 

 through improved methods of propagation to control the extent to 

 which undesirable variations shall enter into the population of future 

 commercial Washington Navel orange groves. 



PLAN OF THE INVESTIGATIONS. 



These investigations have been carried on by means of individual- 

 tree performance records and observations. 



The term " performance record" is used here to mean the record 

 of the number and the commercial quality of fruits borne by indi- 

 vidual trees during a period of years. 



The term ''performance-record plat," as used in connection with 

 these investigations, means a group of trees grown under comparable 

 conditions, selected for the purpose of determining the relative 

 behavior of the trees by means of individual- tree records of pro- 

 duction, observations, and descriptive notes and records. 



The individual-tree performance records made during these investi- 

 gations were secured by giving each tree a number, by marking the 

 trees annually with cloth streamers to prevent their accidental pick- 

 ing by the regular ranch picking crew, by picking each tree sepa- 

 rately and assorting its fruits according to grade and size, by weigh- 

 ing each lot of fruit of each size and grade, by counting the fruits 

 of each lot, and by recording these data on forms arranged especially 

 for this purpose. In preparation for the work of assorting the fruits 

 the season of 1909 was largely spent in citrus packing houses study- 

 ing the grading standards in use in such houses at that time. Pre- 

 hminary to each season's work since then, similar studies have been 

 made in order to true up and improve the judgment of the observer 

 when securing the investigational performance records. 



