80 BULLETIN 813, IT. S. DEPAETMEISTT OF AGEICULTUEE. 



tion of the undesirable strains has been the natural tendency of the 

 bud cutters to secure bud wood from the trees producing the most 

 suckers. In other words, they cut their bud wood from the trees 

 where they could most easily and quickly secure the largest supplies. 

 The method of using fruit-bearing bud wood for the propagation 

 of the citrus varieties, as shown in figure 18, has been evolved in the 

 course of these investigations and has largely eliminated the danger 

 of the unintentional propagation of the vegetative strains of the 

 Eureka lemon. The use of fruit-bearing bud wood naturally results 

 in bud cutters securing most of their bud wood from the most heavily 

 fruited trees, because more fruit wood is available on such trees than 

 on trees of the poor fruiting strains. When performance records are 

 used as a basis for parent-tree selection and only that bud wood used 

 for propagation which bears typical fruits, the danger of propagating 

 the undesirable strains is largely eliminated. 



THE ISOLATION OF STRAINS THROUGH BUD SELECTION. 



The orchards of the Eureka lemon variety in California are made up 

 of trees of many diverse strains which have originated from bud 

 variations. The description and characteristics of some of the 

 important strains have been presented herewith. It is obvious from 

 these data and observations of the behavior of the trees of the different 

 strains that some of them are not worthy of propagation, because of 

 low and inferior production. Other strains mature their fruit during 

 poor marketing seasons when the prices for lemons are usually low. 

 The trees of some of the strains produce fruits low in acidity, of un- 

 desirable shapes for packing, of coarse ugly texture, with little or no 

 juice, or with some other undesirable characteristics. It has been 

 proved that a mixture of strains in orchards is very undesirable and 

 is likely to make the maintenance of such orchards unprofitable. 



After determining the relative value of the different strains for 

 commercial production in California, the next step in these investi- 

 gations was the attempt to isolate each of the important strains 

 through bud selection. This study was made by propagating from 

 typical trees of each strain, selecting the bud wood on the basis of 

 tree-performance records and intimate tree knowledge. Only fruit- 

 bearing bud wood was used for this pupose, with typical fruits of the 

 strain attached to each bud stick. 



The first trees grown from these propagations are now 4 years 

 old from planting. Individual-tree performance records are being 

 secured from some of these progenies. While the performance- 

 record data obtained in the course of this work are incomplete as yet, 

 there is sufficient evidence in hand to warrant the statement that 

 each of the important lemon strains has been isolated through bud 

 selection. This means that the strain characteristics in the progenies 



