I read this ploid focused abstract with interest, and as a layperson. I conclude for my purposes one can cross pretty much any ploids in a plan up to tetra with a margin of success. Without saying anything of the garden merit of the seedlings.
Or does anyone know of a published reference - rather than relying on memory - giving say a simple 4x4 M/F (or 3x3? sans haploid), or larger indicator matrix of ploid combos versus “efficiency / fertility of seed set”, and germination ? Seems like one could construct one from just this abstract as a general guide.
Or assuming the roses in a pair are fertile, why worry, its not practical or predictive, just do the cross and find out (always my default approach).
“Interspecific crosses between diploid rose species and tetraploid cultivars yield triploids …”
"Using such triploids as pollen parents and tetraploid plants as seed parents resulted in relatively high seed set. Although efficiency was lower, reciprocal crosses with the triploid plant as a seed parent also yielded some seedlings.
Screening of the progeny showed that seedlings obtained after a cross between a tetraploid seed parent and a triploid pollen donor are mostly tetraploid.
In the reciprocal cross, both triploids and tetraploid seedlings are found. These results indicate that triploid rose plants form both haploid and diploid pollen and egg cells.
However, in pollen production, the diploid fraction seems to have a competitive advantage over the haploid. Molecular marker (AFLP) data show that markers can be passed on from the diploid species to a tetraploid F2 generation via a triploid F1."
Interploidy crosses in roses: Use of triploids
September 2005Acta Horticulturae 690(690):109-112
Johan Van Huylenbroeck Institute for Agricultural and Fisheries Research
Leen Leus Institute for Agricultural and Fisheries Research
Erik Van Bockstaele Institute for Agricultural and Fisheries Research