14 



The variations in the morphological development of stamens and 

 pistils and in their ability to function as sex organs are to be described 

 as phenomena of intersexualism. The abortion of pollen in reflexed, 

 in crinkled, and in other stamens is seen in flowers that are highly 

 pistillate and functional as females. Conversely extreme loss of 

 femaleness is seen in staminate types in which maleness is highly 

 developed. In these extremes the loss of sex is one-sided. Such 

 one-sided impotence is characteristic of intersexualism as distinct 

 from the sterility of hybridity which tends to affect both sexes in 

 the individual quite the same. 



Cases of sterility in grapes due to hybridity are reported by Detjen 

 (1919) in Fi hybrids between Vitis vinifera (Malaga) and V. rotundi- 

 folia in which flowers of the external form of the perfect hermaphro- 

 dites are mostly or entirely sterile and impotent in both stamens 

 and pistils. Such sterility appears to be largely absent in hybrids 

 between V. vinifera and the more northern species of native American 

 grapes. Many varieties known to have originated thus have per- 

 fect flowers with both sets of sex organs highly functional. A sys- 

 tematic study of known hybrids between V. vinifera and native 

 species from which such a variety as Concord originated is needed 

 to determine to what extent, if at all, sterility from hybridity is 

 present along with intersexualism. 



The results of the breeding work already obtained at the Station 

 indicate clearly that the use of seedless and near-seedless plants 

 as male parents in crosses with varieties that are strongly female 

 (perfect and imperfect hermaphrodites) gives progeny that are 

 strongly female and seed producing. The Fi offspring of many 

 crosses of standard seeded varieties with Hubbard Seedless have 

 all been strongly pistillate, yielding seeded fruit. Weak femaleness 

 (seen in seedless fruits) is in this case dominated or swamped by the 

 strong femaleness of the seed parent. However, the seeded char- 

 acter of Fi individuals is no index of the variation in intersexes 

 that may appear in later generations in which the segregation of 

 at least some plants bearing seedless fruits may be expected. The 

 use of other seedless sorts in such crosses may, however, give different 

 results. 



The most effective course in breeding for the development of seed- 

 less sorts is suggested by the conditions of intersexualism. Most 

 individuals and varieties producing seedless or near-seedless fruits 



