8 BULLETIN 697, U. S, DEPARTMENT OF AGEICULTTJRE. 



mercial inferiority of the product from such trees constitutes one of 

 the important reasons for the systematic selection of bud wood from 

 trees of the right character. 



The diversity of strains of the Marsh variety represented in estab- 

 .lished groves is of great commercial importance to the grapefruit 

 industry, for the reputation and value of the crop depends on the 

 maintenance of a imiform quality. For this reason, the identification 

 of the Marsh strain, which is the most productive and valuable strain 

 of the variety, and the maintenance of the purity of the strain by 

 bud selection are of fundamental importance in the development of 

 the industry. This does not entail any increase in the cost of pro- 

 ducing, handling, or distributing the crop. On the contrary, from 

 the standpoint of cost of production based on the unit cost per box, the 

 production of the best strains can be effected more cheaply than is 

 the case when inferior and less productive strains are present. 



Fruits containing many seeds, such as those of the Seedy strain, are 

 of much less value than those which are commercially seedless. On 

 account of the fact that some of the seedy fruits can not be readily 

 separated after picking from those of the Marsh or other strains, the 

 presence of trees of this strain in estabhshed groves is detrimental to 

 the reputation and value of the crop as a whole. 



The late-ripening characteristic of fruits of the Bell strain is also 

 detrimental to the effort to build up a superior commercial reputation 

 for this variety. The fruits of this strain are difficult to ehminate from 

 the general pick and pack of the groves. Because of their unripe con- 

 dition, if included with fruits of the Marsh strain they tend to detract 

 from the quahty of the whole package and to injure the reputation of 

 the variety. 



OBJECTS OF THE INVESTIGATIONS. 



The objects of these investigations are (1) to determine the fre- 

 quency of occurrence and the nature of bud variations in the Marsh 

 variety of grapefruit, (2) to secure definite information concerning the 

 commercial value of the different strains of this variety by means of 

 individual-tree performance records, (3) to originate and introduce 

 methods for isolating the best strains and controlling variation within 

 them through bud selection based on tree-performance records and 

 definite tree knowledge, (4) to eliminate the trees of inferior strains 

 in estabhshed orchards by top-working them with select buds, and (5) 

 to demonstrate the value and importance of the use of improved 

 methods of propagation based on definite individual-tree knowledge 

 for the improvement of the production of estabhshed orchards and 

 for the conservation and improvement of the variety. 



