The genus Lilium contains a number of ornamental crop species, which are commercially important in many countries. As they are vegetatively propagated, maintaining genetic stability is essential for their efficient conservation. In this study, we investigated the genetic stability of regenerated plants of three cultivars (L. bolanderi ‘Lenora’, L. bolanderi ‘Mount Duckling’ and L. bolanderi ‘Mount Dragon’) and one variety (L. callosum var. flavum) after cryopreservation, compared with fresh (donor) and non-cryopreserved plants using morphological traits and ISSR markers. No differences in morphological parameters including flower, stigma and pollen colour, floral spots, floral direction or polymorphic bands were observed between control (fresh and non-cryopreserved) and cryopreserved plantlets. In addition, based on the resulting UPGMA dendrogram, the four taxa were divided into different clusters. All cryopreserved, non-cryopreserved and fresh plants in each group could be grouped together in a single cluster with more than 97 or 100% similarity. The results suggest a very low level or the absence of genetic variation in terms of morphological and genetic stability among the plants regenerated after cryopreservation.

For the long-term preservation of genetic resources, cryopreservation techniques have been developed for strawberry germplasm, mainly using in vitro-grown shoot tips. In this study, genetic stability was tested under greenhouse conditions for six strawberry accessions (IT232511, PHS0132, IT245810, IT245830, IT245852, and IT245860) derived from the following procedures: (1) conventional propagation (GH: greenhouse maintained); (2) in vitro propagation (TC: tissue culture); (3) pretreatment before cryopreservation (−LN: non-liquid nitrogen exposure); and (4) cryopreservation (+LN: liquid nitrogen exposure). To test the performance of phenotypic traits, we measured six vegetative and five fruit traits. There were no distinct differences in most of the characteristics, but a few traits, such as sugar content and pH of fruits in three accessions, showed higher values in +LN compared to GH. However, the differences disappeared in the first runner generation. To test genetic variations, a total of 102 bands were generated by twelve inter simple sequence repeat (ISSR) primers. A few polymorphic bands were found only in plants derived from TC of IT245860, which was not cryopreserved. The sequencing analysis of four polymorphic bands produced by ISSR_15 showed that none of these sequences matched the characterized genes in NCBI. Phenotypic abnormality was not observed across all plants. This study indicates that cryopreserved plants of the six strawberry accessions are phenotypically and genetically stable. Therefore, the results of this study can help to implement cryobanking of strawberry germplasm.