Colchicine-induced chromosome elimination in potato callus culture more

In crop prebreeding, interspecific hybridisation with wild relatives inevitably introduces undesired traits and needs backcrossing to generate agronomic material. Backcrossing causes genetic reassortments, which for genetically complex crops like the cultivated potato (Solanum tuberosum), requires selection from large progenies to identify commercial material. An alternative approach is to exploit natural instability of chromosomes in vitro to remove chromosomes containing unwanted traits from the initial hybrids without backcrossing. This study investigates the feasibility of inducing chromosome loss within in vitro-grown F1 interspecific hybrids.
Leaf-derived calli from triploid (2n=3x=36) F1 hybrids (S. acaule × S. phureja) were used for callus induction and shoot regeneration. Explants were exposed to various colchicine concentrations in an attempt to induce somatic chromosome loss during callus growth. Regenerants were scored using mapped microsatellite markers to trace the fate of individual chromosomes.
Sub-optimal colchicine application did stimulate chromosome loss; resulting in aneuploids and cytological chimeras. Chromosome loss appeared to be both parental-biased and linkage group-biased. Strategies to exploit this induced instability as part of a conventional breeding program are explored.