INHERITANCE OF SEX IN THE GRAPE 1 



W. D. VALLEAU 



Section of Fruit Breeding, University of Minnesota Experiment 

 Station, St. Paul, Minnesota 

 Since the discovery of Correns in 1907 that in Bryonia 

 the staminate plants produce two kinds of gametes with 

 respect to sex, and the pistillate and hermaphrodites only 

 one, great advances have been made in the study of sex 

 inheritance. 



Shull (1910, '11, '14) has shown that in Lychnis dioica 

 also the staminate plants are heterozygous for the sex 

 genes, while the pistillate ones are homozygous, but that 

 the hermaphrodites are heterozygous for the determiner 

 for femaleness and for the hermaphrodite condition. 

 These hermaphrodites were apparently developed from 

 staminate plants as they bear only partially developed 

 pistils in many flowers, and further, the factor for narrow 

 leaves is linked with the determiner for the hermaphro- 

 ditic condition, while in the normal males it is linked with 

 that for maleness, as pointed out by Shull. Apparently 

 the determiner for femaleness is carried suppressed and 

 linked with the determiner for maleness in the staminate 

 plants. 



A simpler case of sex inheritance than either of the 

 above is that of the sweet pea in which Bateson has shown 

 that genotypically three kinds of plants may be produced ; 

 namely, the normal hermaphrodites, which produce only 

 hermaphrodites when self ed, the pistillates bearing conta- 

 bescent anthers, which when pollinated with pollen from 

 the normal hermaphrodites produce the third type, which 

 is phenotypically the same as the normal hermaphrodites. 

 These when selfed produce hermaphrodites and pistillate 

 plants in a 3:1 ratio, showing them to be heterozygous for 



versify, December, 1915. 



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