Evidence for gametoclonal variation in potato (Solanum tuberosum L.)

Gametoclonal variation that occurs in gametic cells in culture and is recovered in their regenerated derivatives has not been reported in potato (Solanum tuberosum L.). Based on a set of 24 differentiating phenotypic traits, canonical variates analysis genetically distinguished the androgenic (di)haploid (2n = 2x = 24) D4 from its tetraploid (2n = 4x = 48) anther-derived sibs and anther donor JTH/C-107. Nuclear microsatellite analysis over six polymorphic loci indicated that meiotic rearrangements and mutant alleles were primarily associated with the release of gametoclonal variation. The incidence of null alleles in D4 at the loci STACCAS3 and STM0031 was also indicative of mutations occurring within the priming sequence. Microsatellite results were supported by random amplified polymorphic DNA (RAPD) assays that characterized a total of 567 loci (bins) representing 4,258 amplified fragments. Sixty-five new RAPDs that were absent in the anther donor and in either of its parents, viz., S. phureja Juz. & Buk. IVP-35 and S. tuberosum cv. Kufri Jyoti were present in D4, indicating the occurrence of extensive recombinational events. The results have been discussed in the context of microsatellite null alleles providing the most conclusive evidence for gametoclonal variation.