Aneuploidy in the progenies of inter-specific hybrid (AAAB genome) tetraploid potatoes

Summary

Cultivated potatoes (Solanum tuberosum L.) are autotetraploid (AAAA). Wild allotetraploid (AABB) relatives that share the A genome with cultivated potatoes are important for potato breeding; however, it is difficult to perform direct crossings between these two groups due to a post-zygotic crossing barrier called the endosperm balance number (EBN). In this study, the progenies of three exceptional sesquiploid (AAAB) hybrids (stbr₁, srbr₂ and stbr₃) from S. stoloniferum (sto) × S. tuberosum (tbr) were analysed. Five progenies, including selfed stbr, stbr₁ × sto, stbr₁ × tbr, stbr₂ × tbr, and stbr₃ × tbr were investigated in detail in terms of their somatic chromosome numbers. As expected, based on the genomic formula of hybrids, the incidence of aneuploidy was high in the progenies. However, most were aneuploid, with only one or two extra or deleted chromosomes. The results are discussed based on EBN theory.