80 



The Journal of Heredity 



propagations from branch sports have 

 been made in these studies, and so far, 

 the buds from these striking,' hmb varia- 

 tions, representing all of the known 

 strains, have reproduced the charac- 

 teristics of the limb sports. Enough 

 propagations of this character ha\'e been 

 made to prove that all of the known 

 strains of the lemon varieties can be 

 ]jroi)agated in this manner. 



From this, and other available evi- 

 dence, it would seem reasonable to 

 conclude that the different lemon strains 

 in the established orchards have been 

 propagated, often unintentionally, from 

 bud sjjorts. 



FREQUENCY OF BUD VARIATIONS 



In June, 1912, the writer and his 

 associates made a tree census study of a 

 lemon orchard containing about 16,000 

 trees which were 8 years old. It was 

 found in this work that 3,200, (jr 20'^( 

 of the trees in this orchard, were of the 

 undesirable shade tree strain . A similar 

 study was made a Httle later of a 10-acre 

 Eureka orchard 20 years old, from which 

 the buds were secured for the propaga- 

 tion of the larger orchard. It was 

 found that among the 800 trees in this 

 orchard about eighty, or 10%, were of 

 the shade tree strain. In seeking an 

 explanation for the increase in per- 

 centage of the shade trees in the younger 

 orchard, it was learned from the ])ropa- 

 gator that, owing to the larger number 

 of sucker branches formerly used for 

 i:)ropagation ]jurposes (the rapid growing 

 and non-fruit-bearing limbs) in the shade 

 trees as compared with the number of 

 such branches in the productive strain 

 trees, a larger ]jroi)ortion of the bud- 

 wood used for the i)r(Ji)agation of the 

 younger orchard had been cut from the 

 shade trees than from the jjroductive 

 trees. Inasmuch as no distinction was 

 made between the shade trees and the 

 productive trees, and as sucker growth 

 was considered at that time to be 

 just as good as fruit-bearing growth for 

 proi)agation, it was natural that the bud 

 cutters should secure a larger projjorlion 

 of budwood from the shade trees than 

 from the productive trees. 



This experience, in common with 



many similar ones in other orchards, is 

 convincing evidence of the widespread 

 mixtures of strains in established or- 

 chards. It also throws light on the 

 reason why many of the younger 

 lemon orchards have been found to 

 contain a larger jjroportion of the 

 \'igorous growing unproducti\'e trees 

 than the older ones. 



DIFFERENCES IN YIELD 



The trees of some strains of the 

 varieties of lemons studied, have been 

 found to be more jjrolific in the pro- 

 duction of strikingly variable fruits 

 and foliage than (Others. For instance 

 the ijroducti\'e strain trees of the Lisbon 

 variety hax'c been found to be comjjara- 

 tively free from the jjresence of sports, 

 while the trees of the bastard strain 

 have been found to be particularly pro- 

 lific in the jjroduction of strikingly 

 \'ariable fruits, foliage and other tree 

 characteristics. The j^roductive strains 

 of the Eureka and \'illafranca x'arieties 

 have been found to be comparatively 

 free from sports, although some of the 

 ]jroductive strain trees in all of the 

 varieties observed, have been found to 

 produce striking variations. 



In the studies of lemon orchards 

 where this matter has received par- 

 ticular attention, \'ariations of fruit or 

 foliage characteristics have been ob- 

 ser\'ed in about 75% of the trees. Some 

 orchards have been found to contain 

 but few trees showing variations, while 

 others have a large number of trees 

 ])roducing such variations. The num- 

 iDcr of variations found in orchards 

 depends largely on the number of trees 

 belonging to the strains which pro- 

 duce a high i)ercentage of variable 

 fruits. 



The frequency of Inul \arialion in 

 lemon varieties is much greater than 

 has heretofore been thought to be the 

 case. The continued study of this 

 condition has led to the discovery of 

 many variations which had not been 

 noticed Ix'fore. In fact, the frequency 

 and imjjortance of the bud variations 

 of the lemon can only lie ap])reciated 

 by those who have become familiar by 

 actual experience with the strains, the 



