Abscission of Flowers and Fruits of the Apple gi 



different shapes. Furthermore, they vary in color, some being ivory 

 white, others yellowish, others hyaline in appearance. All this suggests 

 a difference in quality, such as might result from cross-pollination, for 

 example. 



Number. of seeds and seed value. — As shown above, the seed value as 

 expressed by the length of the embryo may vary in the different fruits 

 even tho the number of seeds is the same. It is entirely possible that 

 a many-seeded fruit may have a seed value which is below the normal 

 for that number. It ma>' be equal to, and in some cases even less than, 

 the seed value of a fruit with few seeds. Such an assumption is borne 

 out by the fact that in a large number of three-seeded Baldwin fruits, 

 seventy per cent of the embr\'os were above medium length — five milli- 

 meters — while in many-seeded fruits of the same variety only about 

 fifty per cent of the embryos were large. If the ratio of the weight of 

 the spur to the weight of the fruit is greater in a few-seeded fruit than 

 in a many-seeded fruit borne on a similarly located spur of equal weight, 

 one would be justified in assuming that the seed value of the latter fruit 

 was below normal. A specific case may be taken for example as follows: 



Weight Weight 



Number of seeds of spurs of fruit 



(grams) (grams) 



2 2.05 49.1 



5 2.00 44.3 



5 2 . 00 62 . 7 



These spurs were borne on the same twig and they produced their fruits 

 under similar external conditions so far as could be seen. Obviously, 

 the five-seeded fruit that w^eighs only 44.3 grams has a seed value below 

 normal. This seed value is equivalent to that of a few-seeded fruit. 

 There may be found a fruit weighing less than 49 grams which nevertheless 

 has a high seed value. Such a fruit, however, would be on a spur weighing 

 less than two grams; thus, a fruit with four seeds, weighing 35.5 grams, 

 was produced on a spur that weighed one gram. 



It therefore becomes necessar\^ to modify the general statement that 

 the size of fruit is proportional to the niunber of seeds. It would be 

 more nearly accurate to say that the vigor of the individual spur and 

 the seed value of the individual fruit determine the size of the fruits 

 derived from the same limb and borne under othenv^ise similar conditions. 

 This statement includes the prominent part played by the spur, and it 

 also emphasizes seed value rather than number of seeds. It is, of course, 

 very necessary to choose spurs borne under otherwise similar conditions, 

 as is shown later. 



205 



