60 MANUAL OF AMERICAN GRAPE-GROWING 



but little in either theory or fact to substantiate the belief 

 of -those who say that varieties once established can be im- 

 proved ; or, on the other hand, that they degenerate. Present 

 knowledge and experience indicate that heredity is all but 

 complete in varieties propagated from parts of plants. The 

 multitude of grapes in any variety, all from one seed, are mor- 

 phologically one individual. A few kinds of grapes go back to 

 Christ's time, and these seem to agree almost perfectly with 

 the descriptions of them made by Roman writers 2000 years 

 ago. How, then, can the differences between vines of a variety 

 in every vineyard in the land be explained ? 



Ample explanation is found in "nurture" to account for the 

 variation in vines without involving a change in "Nature." 

 Soil, sunlight, moisture, insects, disease, plant-food, and the 

 stock in the case of grafted vines, give every vine a distinct 

 environment and hence a distinct individuality of its own. 

 Peculiarities in a vine appear and disappear with the individual. 

 A variety can be changed temporarily by its environment, but 

 remove the incidental forces and it snaps back into its same old 

 self. 



Heredity is not quite complete in the grape, however; for, 

 now and then, sports or mutations appear which are permanent 

 and, if sufficiently different, become a strain of the parent 

 variety or possibly a new variety. There are several such 

 sports of the Concord under cultivation. The grape-grower 

 can tell these sports from the modifications brought about by 

 environment only by propagation. If a variation is transmitted 

 unchanged through successive generations of the grape, as 

 occasionally happens, it may be looked on as a new form. 

 "Pedigreed" vines, then, should be subject to a test of several 

 generations in an experimental vineyard before the grape- 

 grower pays the price demanded for the supposed improvement. 



