I know this has probably been covered many times here in the past.
For best fertility, is it better to use a diploid as seed parent with tetraploid pollen or a tetraploid as seed parent with diploid pollen?
This may have to do with the endosperm balance, but at least experimentally, it seems much more productive to use the diploid as seed parent and tetraploid as pollen parent (i.e., you’ll get a fairly large seed set this way). Most of those offspring would probably be triploid. On the other hand, low seed set using the tetraploid as seed parent and diploid as pollen parent might be offset by a high proportion of unusual offspring (i.e. tetraploid seedlings from 2n pollen coming from the 2x parent instead of normal n pollen, which wouldn’t make the cut). It seems to me that it would be hard to expect to get triploids with equal frequency going either direction.
Thanks Stefan. I was hoping to hear this. My diploid would be easier to use as seed parent in this case.