322 POMOLOGY 



there is no significant difference between the total yield of 

 the trees of high yielding parents and low yielding parents." ^ 



Stewart ^ reports an experiment in which trees showing 

 marked variation in yield and color were propagated and 

 planted for observation. At the time of his report, however, 

 no progress had been made which would indicate that such 

 superiority had been transmitted, thus again pointing to the 

 conclusion that the differences were due to environment. 



Macoun ^ also propagated some trees which showed 

 marked variation in yield, amounting to 100 and 200 per 

 cent difference, and records were kept on the yields from 

 the trees. However, no decided evidence is at hand after 

 they have produced three crops to substantiate any claim 

 that they will be superior in bearing. 



Extensive observations have been made in recent years 

 of bud variation of orange, lemon, and grapefruit trees by 

 Shamel ^ and others. These fruits, particularly certain va- 

 rieties, are found to be in a very variable condition, and bud- 

 sports are frequently observed with a number of the char- 

 acters of both tree and fruit. In recording the performance 

 of the trees, such characters are observed as : habits of growth 

 of the trees; characteristics of the bloom; season and amount 

 of production of fruit; size, shape, and color of fruit; texture, 

 thickness, and appearance of the rind; amount and quality 

 of the juice; and other tree and fruit characteristics. 



Shamel states in regard to lemon trees that "The produc- 

 tive strains in every case known, produce a higher percent- 

 age of first-grade commercial lemons than the unproductive 



1 Whitten, J. C. Mo. Agr. Exp. Sta. Bull. 163. p. 55. 1919. 



2 Stewart, J. P. Penn. Agr. Exp. Sta. Bull. 134. 



3 Macoun, W. Dominion Exp. Farmers Bull. 86. 1916. 



* Shamel, A. D. Bud variation in lemons. Jour. Heredity, Feb., 1917. 

 Lemon orchard from buds of single selected tree. Jour. Heredity, 

 Nov., 1918. 



