1911.] PUBLIC DOCUMENT — No. 31. 170 



advice and criticisiu, and to Prof. F. A. Waiigli as well, wlio 

 lias given many helpful suggestions. The chemical work has 

 been under the direction of Dr. Charles Wellington, and assist- 

 ance in the analytical work has been rendered by ^Ir. E, L. 

 Winn and ]\lr, B. Ostrolenk of the senior class in the college. 

 Many experiment station horticulturists and fruit growers in 

 many sections of the country have aided by giving information 

 and by furnishing samples of apples. It is impossible to name 

 them all here, but their many favors are here acknowledged and 

 hearty appreciation extended. 



II. THE CAUSES OF VARIETAL VARIATION. 



The causes of the great ditlerences in apple varieties may 1)0 

 grouped under three heads: those arising from (1) cultural 

 conditions, (2) differences in soil types, (3) difierences in 

 climate. 



Cultural Variations. 



1'he methods pursued in the growing and in the care of the 

 trees have great influence on the character of the fruit. It is 

 alfected in every way, in size, form, color, k(^e])ing quality, ship- 

 ping quality and dessert quality. These variations have been 

 given only incidental investigation of such jdiases as relate 

 directly to the climatic differences that have been the special 

 object of study. A few of these may, however, be given pass- 

 ing attention at this point. 



Every orchardist growing any number of trees is aware that 

 there are great differences in the individuality of the trees, even 

 Avhen grown in the same orchard and under ajiparently identical 

 conditions of climate and soil. One tree may be very produc- 

 tive and its neighbor only moderately so. The apples may differ 

 in nuiuy of their characters. Further along in this paper some 

 data are presented bearing on this question (see page 194). 

 These individual differences have been ascribed to various 

 causes, the principal ones of which are. perhaps, those of bud 

 \ariations or varietal " strains." and that of the influence of 

 the stock. 



The method of handling the soil has great influence on the 

 fruit, especially whether the orchard is in sod or is cultivated. 



