July IS. 1915 Inheritance of Certain Characters of Grapes 



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has been greatly complicated, yet until we are able to find such pure 

 colors and to study their various combinations our knowledge of the 

 color composition of many varieties will probably be only conjectural. 



The thousands of seedlings which have been fruited have made possible 

 the formulation of but two general laws: (i) White is a pure color; and 

 (2) white is recessive to both black and red. White, yellow, green, and 

 amber are all considered under the one term and are regarded as being 

 the absence of red and black. 



No black variety that has been tested to an extent sufficient to make 

 the results at all conclusive has proved pure for blackness. Some have a 

 factor for red; others seem to contain only black and its absence, white, 

 while still others have both white and red progeny. 



In order to simplify the study of red varieties, it has seemed best to 

 divide the seedlings into two shades, the light or medium reds and those 

 ranging from dark red to purple. Those in the second classification are 

 probably red plus either an intensifying factor or various amounts of 

 black. Such a division is somewhat arbitrary and some colors are diffi- 

 cult to place, but, in general, it is a helpful arrangement. Table I gives 

 the result of combining similar colors and shows that the results obtained 

 from crosses of red varieties are as diverse as those from the black. The 

 table includes mainly pure seedlings. 



Table I. — Results of crossing grapes of similar colors 



Table II illustrates the variation in color composition among most of 

 the varieties given above in the cross black X black and shows the 

 number of varieties which fall in similar groups. From this table it 

 will be seen that 15 black varieties have given only black seedlings, but 

 the number of seedlings is not large enough to be conclusive. 

 Table II. — Color groups of pure seedlings of black varieties of grapes 



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