64 BTJLLETIl^ 813, U. S. DEPARTMEI^T OF AGRICULTURE. 



proved to be true bud mutations usually appear more frequently and 

 more abundantly in trees of some of tlie unproductive or otherwise 

 undesirable strains tban they do in trees of the standard strain of the 

 variety. 



The presence of variable fruits on all the trees and the fact that 

 some trees produce many more such fruits than other trees emphasize 

 the need of having reliable individual-tree performance records for 

 use as a basis in selecting trees from which bud wood can be taken for 

 commercial propagations. It is not sufficient to know that certain 

 trees produce heavy crops, but data must be available to show the 

 number and kind of variations on the trees, so that only those will 

 be chosen which bear the most uniform and desirable fruit. 



In Table X are presented the total number of the different variable 

 forms which were recorded for three years on the trees listed in Table 

 VIII. The typical fruits of the Pear-Shape strain produced on the 

 trees Hsted in ranks 71 and 104 are recorded as bottle shaped, and 

 other fruits on the same trees having a tendency toward that typical 

 shape are classed as collared. These collared fruits are believed to 

 be of a different character from the collared fruits commonly found 

 on trees of other strains, but being hke them in appearance they 

 were Hsted in the same class. Propagations have been made to 

 determine this point. . 



Wherever no record was made of any factor for one or more months 

 it is thought that the most practicable method of computing the 

 monthly averages in Table VIII is by dividing the monthly totals 

 by the number of months represented in each total. For example, 

 the averages for the production of Green-grade fruit by the tree in rank 

 1 in Table VIII during July, August, September, and October were 

 computed by dividing the monthly totals by the factor 5, as there 

 are records for five years during those months. In November, 

 December, and January the records for six years are available. In 

 February the pickings were missed in 1914 and 1917 and the average 

 for that month is obtained by using the factor 4. In March records 

 were secured during five years but the crops harvested in that month 

 in 1914 and 1917 were in reality the yields for two months in each 

 case, so the factor 7 has been used in determining the average for 

 that month. It is recognized that this resultuig average is not strictly 

 accurate, but it is believed to represent more nearly the correct aver- 

 age for the period than any other figure that can be presented in 

 this table. Because of the use of different factors, as just mentioned, 

 the totals of the monthly averages are not equivalent to the average 

 for the yearly totals. Other instances in this and other tables will 

 bo found where the decimal portions of averages of total records do 

 not exactly correspond with the totals of the averages of the corre- 

 sponding numbers. This is due to the small errors occasioned by the 

 practice of retaining only two decimal places in average figures. 



