I've been thinking about making some hybrid citrus (still a long ways off) and I was wondering how polyembryony is in inherited by seedlings.

For example I cross something with a high degree of polyembryony, like a grapefruit with something with a low degree polyembryony, like a meyer lemon. What would the offspring's seeds be like?

You'll never know until you try. On top of that each plant from each seed will be different.

I've reading a bit about people doings often. Or at least planning on it. I think I will be one of those planning on doing it. I would like to try it with a blood orange.

Dr. Frost (UCR) crossed a Imperial Grapefruit with eight different pollen parents and obtained 626 seeds. The 626 seeds produced 788 seedling trees, or 1.26 seedling trees per seed. Of the 728 seeds produced 264 seeds were gametic and 524 seeds were nucellar. Therefore 66 percent were nucellar.

In another experiment, Dr. Frost crossed a Marsh grapefruit with six different pollen parents and obtained 207 seeds. The 207 seeds produced 223 seedling trees, or 1.08 seedling trees per seed. Of the 207 seeds produced only 10 seeds were gametic and 213 seeds were nucellar. Therefore 96 percent were nucellar. Millet (452-)

Many of the Citrus rootstock hybrids are polyembryonic( Citrange, Swingle etc) They have also been recrossed with other vars in rootstock breeding. Maybe researching rootstock breeding will give some answers??

Mike has a bit of information on his experience.

http://www.homecitrusgrowers.co.uk/hybridseedlings.html