Abscission of Flowers and Fruits of the Apple 



89 



The data show that when the weight of the spur is constant, the size 

 of the fruit varies with the number of seeds. In other words, the size 

 of the fruit is determined chiefly by the vigor of the spur and the seed 

 content of the fruit. 



Weight of spur constant, number of seeds constant, size of embryo varying. — 

 Theoretically, according to one interpretation of the above hypothesis, 

 if spurs of approximately equal vigor are chosen which bear fruits con- 

 taining the same number of seeds, the fruits borne on these spurs should 

 be approximately equal in weight. Or, stated in a different way, if the 

 fruits vary in size while the seed number remains the same in each, a 

 difference would be found in the vigor of the spurs producing these fruits, 

 and furthermore one would expect to find the largest apple on the most 

 vigorous spur. That these theoretical results are not always obtained 

 may be seen from the examples in table 43 : 



TABLE 43. Weights of Fruits Having the Same Number of Seeds, 

 AND Weights of the Spurs That Bear the Fruits 



Lot 



Variety 



Number 



of 



seeds 



Weight 

 of fruit 

 (grams) 



Weight 

 of spur 

 (grams) 



Baldwin 



Baldwin 



Tompkins King 



4 

 4 



4 

 4 



6 

 6 



6 

 6 



5 

 5 



41 

 29 



37 

 24 



12 

 07 



90 

 86 



4.28 

 3.20 



3-55 

 1 .90 



2.54 

 2.59 



These data seem to disprove the existence of a direct relation between 

 size of fruit, vigor of spur, and number of seeds. The emphasis, however, 

 is to be placed on seed content rather than mere number of seeds. 



In studying the seeds, one cannot help noticing marked differences 

 in the size of the seeds in given fruits. The embrj^os in the seeds likewise 

 show considerable variation. The embryo is readily dissected from the 

 seed by placing the seed flatwise between the thumb and the forefinger, 

 with the lateral edge upward, cutting the edge with a sharp scalpel, and 

 pressing the embryo out of the seed coat. 



In several cases the number of embryos found in the seeds of a given 

 fruit and the length of the individual embryo were recorded, along with 

 the weight of the fruit and the weight of the spur on which the fruit 

 was borne. These data are given in table 44. The figures under the 

 column headed Length of embryo show the number of seeds in each fruit 

 and the length in millimeters of the embryo in each seed; for example, 



-^03 



