Analysis of nuclear and chloroplast DNA in plants regenerated from cryopreserved shoot-tips of potato

Shoot-tips derived from S. tuberosum cultivar Brodick were cryopreserved us ing the encapsulation/dehydration technique. Total DNA was extracted from 3 0 in vitro plantlets of Brodick regenerated from surviving shoot-tips. DNA was digested with Bam HI and examined using DNA-DNA hybridisation analysis. Fractionation of the digested DNA showed stability of the nuclear-chloropl ast genomic complex and identical chloroplast-DNA fragments were detected i n all regenerated plantlets. This suggests that the observed nuclear DNA fr agments and the chloroplast genome are stable in potato plants regenerated from cryopreserved shoot-tips. This study extends the range of molecular bi ological techniques which can be applied to examine post-cryogenic storage stability in cryopreserved plant germplasm.