The genetics and linguistics of delicious frankenfruit

Have you ever encountered a pluot, plumcot, aprium, or peacotum? You can figure out their constituent parts based on the linguistic roots, but they don't map perfectly.

A plumcot is genetically 50/50 plum/apricot, although linguistically, it's 4/7 plum, 3/7 apricot (close enough, but plumicot and pluicot would have mapped perfectly).

A pluot is, genetically, 75% plum, 25% apricot. Practically speaking, that means it's 50% plumcot and 50% straight-plum, but linguistically you'd expect it to be the same thing as pluot, just with smaller roots (you loose the m on the plum, but also the c on the cot). To further complicate matters, I know the Glover Park/Georgetown Whole Foods sells pluots as plumcots.

Genetically, an aprium is 75% apricot, 25% plum. However, linguistically you'd expect the aprium to be 2/3 apricot (APRI-um), and 1/3 plum (apri-UM).

Finally, we arrive at the peacotum – a very much more complicated proposition. Botanically speaking, it's supposedly equal parts peach, apricot, and plum, which genetically speaking is impossible. Unless you had some very complex multi-generational system of mating that well approximates a 1:1:1 split – the pluot is a basic example of this, as it takes two levels mating to produce (one which results in a 50/50 split between plum and apricot, and another which mates this frankenfruit with a regular old plum). I'd guess that within four generations you could come very close to achieving a 1:1:1 mix (say, 16 great, great grandparents, each original fruit gets 5 gggparents, except one which gets 6).

To complicate matters further, I've assumed that the linguistic breakdown takes each letter of the hybrid and determines genetics based on the proportion of letters which come from each original fruit. However, an alternative way to do it would be to use the proportion of letters taken from the original fruit to denote its genetic contribution, as opposed to using the percentage of the new word which comes from the original fruit. So, for example, a 1:1 cross between an pear and a grapefruit would be an pearuit (or pearruit, or peauit, or peit) under the system I was using, but it would be pefruit under the alternative system.

Disclaimer: I am neither geneticist, mathematician, linguist, grocer, nor farmer.