4 IMPEOVEMENT OF CITRUS FRUITS THROUGH BUD SELECTION. 



recent date, the demand for trees of these varieties has been greater 

 than could be supplied, and it has not been practicable to wait until 

 performance records of individual trees could be secured. It was onl}" 

 possible to propagate stock true to variety, which under the existing 

 conditions thus far has been the one consideration of vital importance 

 to the growers of citrus fruits. In fact, it was usually considered 

 that an}^ bud from a Washington Navel tree, for example, would pro- 

 duce a Washington Navel tree like its parent, and the possibilities ot 

 bud variation were not seriously considered. 



The owner of a pomelo grove in San Diego County observed that a 

 few of the trees purchased a number of years ago, after reaching bear- 

 ing age, produced large crops of tine seedless fruits, while others near 

 by were not only light bearers but produced a large proportion of 

 fruits containing many seeds and of undesirable size and otherwise 

 unprofitable. In planning for the planting of a new and larger grove 

 this owner selected the two trees in the original plantation which he 

 had observed were consistently larger yielders of desirable fruits. He 

 cut all of the buds for propagating the trees for his new grove from 

 these two trees. The new grove is now in full bearing and produces 

 uniformly a large yield of seedless fruits of desirable size and shape. 

 This grove is a striking example of the benefits to be gained from bud 

 selection, as shown by comparison with the older groves where bud 

 selection was not practiced. 



These observations were made preliminary to the undertaking of 

 an investigation by the Bureau of Plant Industrj" of the effect of bud 

 selection in response to the urgent desire of the citrus growers of Cali- 

 fornia. After going over the ground and noting many examples of 

 individual variation it was decided to undertake a systematic study of 

 the variation of citrus trees in southern California, and the writer 

 was directed to begin work. Several months were spent in a study 

 of groves in different sections, so that suitable locations could he 

 selected where the conditions were such that the data obtained would 

 be reliable and of permanent value. As a result of the friendly and 

 generous spirit of cooperation evinced b}^ the growers it was possible, 

 in every case where it was thought best to undertake this work, to 

 make satisfactory arrangements to carry on the investigations with- 

 out expense to the Bureau for as long a period as might prove neces- 

 sary. Owing to various causes of variation in the yield of trees, such 

 as seasonal changes, it is planned to continue the study of a given tree 

 for at least fiv^e years before conclusions are drawn as to its produc- 

 tive behavior or its relative value as a source of buds for propagation. 



The work has been carried through one season, and although the 

 data obtained are far too meager to be conclu.sive in any way they are 

 verj^ suggestive as to the practical possibilities and commercial 



[Cir. 77] 



