244 EXPERIMENT STATION. [Jan. 



gation is seen in apples grown near large bodies of water, which 

 lower the temj^erature at this season of the year, and in seasons 

 when the tem^Derature is low owing to seasonal fluctuations. 

 This influence is also seen in the form of apples in different 

 parts of the tree. Those in the lower north portion are more 

 elongated than those from the warmer, upper south portion. 



8. Seasonal temperature aft'ects the size of apples, a cool 

 season resulting in smaller fruit. This is marked only in full- 

 season varieties, and is especially noticeable in the more north- 

 erly portions of their distribution. On the other hand, in the 

 extreme south a variety is apt to be smaller than when grown in 

 a somewhat cooler climate. 



9. For convenience in discussion, IvTorth America may be 

 divided into seven apple belts, each having a fairly character- 

 istic list of varieties. These are named and illustrated in the 

 text. 



10. Some varieties are of wide distribution; others more or 

 less limited. Varietal qualities favoring a wide distribution are 

 (1) great hardiness of tree, (2) a short season of development, 

 (3) great vigor and ability to thrive under generally unfa- 

 vorable conditions, (4) productiveness and good market qual- 

 ities. 



11. The northern limit of apple growing is fixed by the min- 

 imum winter temperature, and the southern limit by the heat 

 of the hottest part of the summer, occurring usually in July or 

 Augaist. 



12. The attainment of the highest quality, appearance and 

 keeping quality is very largely dependent on the warmth and 

 length of the growing season. This may be measured with fair 

 satisfaction for the apple-growing regions of ISTorth America by 

 an average of the mean temperatures for the months of March 

 to September inclusive. This is called the mean summer tem- 

 perature, and give temperatures ranging from 52° to 72°. 



13. Factors determining the mean summer temperature in a 

 given orchard are (1) latitude, (2) elevation, (3) site and as- 

 pect, (4) soil, (5) culture, (G) prevailing winds, (7) sunshine. 



14. The optimum mean sunnncr temperature for different va- 

 rieties may be determined with fair satisfaction, and some deter- 



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