b IMPROVEMENT OF CITRUS FRUITS THROUGH BUD SELECTION, 



The influence of the seedling stock on the development of the buds 

 from select parent trees will be investigated, and the importance of 

 the selection of seedlings for budding purposes will be studied. There 

 is no question as to the fact that citrus seedlings vary greatl}^ in vigor 

 and habit of growth and in other characteristics, but the effect of 

 these variations on the development of the scions is a matter as yet 

 undetermined, although thej'are probably of importance so far as the 

 development and behavior of the tree is concerned. 



At the time of picking careful photographic and other notes are 

 made of each tree, its fruit, and other characteristics, so that, if results 

 warrant, score cards and standards of selection may be devised intelli- 

 gently for the different varieties of citrus fruits to aid in the study 

 and selection of breeding stock. 



The demonstration of methods for the elimination of unproductive 

 or worthless trees in established citrus groves by rebuddingor replant- 

 ing and the establishment of reliable sources of uniform stock of citrus 

 fruits for new plantings are the ultimate aim and object of this work. 

 The data secured in the course of this work will constitute "pedigree 

 records,"' based on the performance of the trees studied. The value 

 of such pedigrees will depend on the conditions under which the data 

 are obtained and the accuracy and care used in picking, sizing, sort- 

 ing, and weighing the fruit. 



VARIETIES OF CITRUS FRUITS SELECTED FOR PERFORMANCE 



RECORDS. 



The Washington Navel orange was the variety selected with which 

 to start the work. The commercial success of this variety' is fully 

 established in California, Its introduction into southern California is 

 of comparatively recent date and all of the details relative to its intro- 

 duction and distribution are fully known. There is probably less 

 variation in the groves of this variety than in groves of other varieties 

 now growing in southern California, so that if bud variation is found 

 to be important in the case of the Washington Navel orange it is 

 probably of more importance to the other varieties. As the two 

 parent trees from which all the trees of the Washington Navel orange 

 in southern California have descended are now growing at Riverside, 

 Cal., there is an unparalleled oppoi-tunity to studj^ the influences of 

 change of environment and bud variation, as shown by a comparison 

 of the parents with their descendants, man v groves of which are grow- 

 ing under widely differing conditions of soil, altitude, climate, and 

 culture. The history of practically every Washington Navel tree in 

 California can easily and definitely be traced to the two original trees, 

 SO that clear-cut conclusions can be drawn as to the influence of differ- 

 ent factors on the development of the variety since its introduction. 

 The fine quality of the Washington Navel orange and its high value 



[Cir. 77] 



