Breeding Rotundifolia Grapes 
27 
When James is crossed with Dark Male No. 2 the resulting hybrids 
are all dark in color. It has been shown that James is heterozygous 
for the white and for the black colors, therefore, the Dark Male vine No. 
2 that was used in this cross must he homozygous, carrying only the 
dark color. The factor for the white color in James is latent and is 
also recessive to the factor for the dark color in this male vine. 
The results that were obtained from James are of special importance, 
for it is regarded as a valuable variety for breeding purposes. The 
James is a vigorous grower, very prolific, and produces large berries 
which cling fairly well to the cluster, and it is one of the best shippers 
of the group. That this variety can be used as one of the parents 
in the production of either black, or white fruiting varieties, is evident 
from results obtained. Since this variety possesses some excellent char¬ 
acters that are not found in the Scuppernong it may become of con¬ 
siderable importance in the production of white varieties. 
TABLE NO. 4. 
Table Showing Color of Thomas Hybrids. 
Cross 
Color of Plants 
Color of Fruit 
Thomas X Light Male No. 1.. .. 
Light none 
White none 
Black none 
Dark 212 
Red 29 
Thomas X Dark Male No. 2....... 
Light none 
White none 
Dark 66 
Dark 3 
The light male vine that was used in this cross is known to be one 
that has the factor for the white color only. Therefore, these results 
show that Thomas is homozygous for red, and that red is dominant 
over white (See Fig. 13). Only 29 of the seedlings of this cross have 
fruited, and all of these have produced red fruit, the shades of which 
varied from wine color to that of almost black. These results are of 
especial value because the Thomas is the only red variety of this spe¬ 
cies that is now widely cultivated. The question of producing new red 
varieties of this species now becomes a very simple matter, and the need 
for such work is very apparent, when we consider that Thomas pos¬ 
sesses some objectionable as well as some desirable characters. 
It is to be regretted that none of the seedlings of Thomas crossed 
with a pure dark male vine have matured their fruits far enough to deter¬ 
mine with any degree of accuracy whether they will be black or 
whether they will be red in color. From the scarcity of the red fruiting 
vines in Nature, also from the various shades of red that fairly lose 
themselves within the black, we assume that the black color is dominant 
over that of the red; and that therefore, all of these seedlings that 
are destined to bear will produce black fruit. 
While no white fruiting seedlings have been produced from the 
Thomas crossed with a light male vine, we believe that such white 
seedlings can be produced in the second generation. These first genera¬ 
tion hybrids possess the white character in recessive form. When such 
