"requires three different chromosomes to line up in order to express itself."

If it is just the presence of three specific chromosomes from a muscadine parent in a true_grape/muscadine hybrid... then a cross between two such hybrids should result in 100% of seedlings with the muscat flavor trait.

This is dependent upon the hybrid plants being diploid for each chromosome. If the hybrids are generally diploid, but are haploid for each of the three muscadine chromosomes, the percentage drops to 1/64. If one parent is fully diploid and the other haploid for the muscadine chromosomes, you get 1/8.

If there is more than one set of three muscadine parent chromosomes which will result in the muscat flavor in progeny, or alternate ploidy issues... then it gets more complicated.

Do you have any vitis that are 1/4 muscadine? I would be interested in getting some that have descent quality grapes.

Generally when breeding in order to get the most desirable traits from two parents you would need to take a number of the half breeds and then cross them with each other. After so many crosses just by chance some traits will arrange themselves in the correct order.

I mean if you have one grape with great flavor and another grape with great disease reistance then crossing them would usually result in something in between unless there are dominant/reccessive traits involved then the dominant traits will usually show.

But if you take those cross breeds and cross them with each other then some will have a large degree of disease resistance, some will have medium, some low, some will have great flavor, some medium some low, and those traits will combine in different ways so a certain percentage of them would have the most desirable of each trait.

The only problem is how many babies must you make to get that? Probably a lot. It's just a matter of chance I guess and picking whichever offspring is most desirable.

But rather than constantly cross breeding specices I would be crossing them with their sisters and crossing them back with the parents in order to maximize the most desirable traits.

Example: take the muscat flavored grape. Cross it with a muscadine for hardiness. Cross breed that with its siblings that exibit the most desirable traits (hardy and closest flavor). Then pick the best ones out of those crosses and cross it back with the muscat flavored parent! You should end up with a hardier version of the muscat!

Actually in this case I would cross the 1/2 muscadines with a muscat again (to make sure they now have the right number of chromosomes and compatibility). Then out of thesee 1/4 breeds choose the one with the closest flavor and best disease resistance etc. then cross it back with the muscat parent. Again grow several seeds find the best specimen. I don't know if that would be hardy enough to grow in the south though. might want to try using a Blanc Du Bois which has muscat flavor but is restistant to southern disease use that in some of your crosses instead of the pure muscat.