Laura Galloway and UVA EEBIO alumna Brittany Sutherland recently published a study on reproduction between different plant ploidy levels in Ecology and Evolution. They combined controlled backcrosses between interploidy hybrids and their parental cytotypes with surveys of naturally-occurring mixed-ploidy populations in Europe and North America. They find that triploid hybrids (which occur between diploid and tetraploid plants) face substantial barriers to survival and reproduction, while pentaploid hybrids (which occur between tetraploid and hexaploidy plants) retain fertility and readily backcross with their parental cytotypes in both controlled settings and in nature. No triploids were found in natural populations, but pentaploids and potential aneuploids were abundant (see figure).
Sutherland, B.L. and L.F. Galloway. 2021. Variation in heteroploid reproduction and gene flow across a polyploid complex: One size does not fit all. Ecology and Evolution Early View.