Abscission of Flowers and Fruits of the Apple 



63 



the soil, the temperature, the humidity, cloudiness, and other environ- 

 mental conditions, have marked influence on the nutrition. 



In the summer of 1914, the fruit borne on spurs arising from 19 12 

 or 1 9 13 wood was found near the end of the season's growth in most 

 cases. The percentage of flower-bearing spurs that set fruit in the 

 terminal parts of a given year's growth, as compared to the set on the spurs 

 in the lower halves of the same twigs, is shown in table 14. It is seen 



TABLE 14. Set of Fruit on Spurs Formed on Different Parts of 



A Given Year's Growth 



that there are fewer flower-bearing spurs in the basal half of the year's 

 growth, and a smaller percentage of these basal spurs set fruit. The 

 results would probably have been more striking if only the relatively 

 short twigs had been considered. The long twigs, as has been mentioned, 

 usually show a middle zone of weak or dormant buds, which are generally 

 preceded by fruit-setting spurs. In such twigs, fruit-setting spurs would 

 be found in the basal half of the year's growth. 



relation between number of flowers to the spur, and ability of 



THE spur to set FRUIT 



The number of flowers on an apple spur varies from two to seven. 

 Casual observations seemed to indicate that there is a relation between 

 the number of flowers produced by the spur and its ability to bear fruit. 

 Consequently, a more careful study of this question was undertaken. 



Average number of flowers on spurs holding fruit for varying lengths of time 



Records were made of the number of flowers borne on spurs that lost 

 all fruit at the first drop, on those that held fruit until the June drop 

 but not longer, and on those that finally set fruit. The data are recorded 

 in table 15: 



12 177 



