No. .397] INHERITANCE OF 



557 



flowers suppression of the female determiner has taken 

 place. Booth (1902) and Dorsey (1912) have shown that 

 in practically all staminate grape Mowers suppressed 

 pistils are found. In some cases under cultivation and in 

 rare instances in the wild state, tlie suppression ol pistils 

 is less marked and fairly well developed to perfectly de- 

 veloped pistils are formed. On individual plants occa- 

 sionally all gradations from staminate to functionally 

 hermaphroditic flowers are found. 



A third type found under cultivation but which is ex- 

 tremely rare in the wild, is the functional hermaphrodite 

 bearing all hermaphroditic flowers. A discussion regard- 

 ing the probable origin of this type will be taken up later. 



Although breeding work has been carried on for the 

 past twenty-five or thirty years in this country with the 

 grape, apparently little attention has been given to the 

 inheritance of the various flower types, although a knowl- 

 edge of sex inheritance would be of much value to the 

 breeder. In 1914 Anthony published valuable data on sex 

 inheritance in the grape, but gave no satisfactory inter- 

 pretation of the results. In 1915 the data again appeared 

 in more detail (Hedrick and Anthony, 1915), and, as no 

 further attempt was made to interpret the results, the 

 writer wishes to present the following as a probable ex- 

 planation of sex inheritance in the grape, or at least as a 

 working hypothesis for the interpretation of further 

 results which may be obtained. 



For the reason that in diecious plants there are appar- 

 ently definite determiners for maleness as well as female- 

 ness, while in animals it is supposed that males are pro- 

 duced when only one dose of the 

 present, while females are produced 

 present, it seems well to use different s? 

 the sex determiners of plants from 

 Therefore, those suggested by Shull 

 which "the female is assumed to be 

 goto," will be used in the following i 

 FF to represent a female and FM to represent 



doses are 

 designate 



n am el v 



