Analysis of sequences of ITS1 internal transcribed spacer and 5.8S ribosome gene of Malus species

The nucleotide sequence of the ITS1-5.8S ribosomal DNA spacer fragment was determined for 41 samples of the Malus species. The total length of compared sequences ranged from 389 to 392 bp. The nucleotide sequence of the 5.8S gene within the genus was highly conserved. The level of polymorphism of ITS1 region comprised 14%. Both species- and group-specific substitutions were identified. The analysis of M. orientalis and M. turkmenorum sequences revealed their full identity, which indicates the need to perform more research with a larger number of samples of both species from other collections to clarify the taxonomic status of the M. turkmenorum species. The previous findings on the synonymy of species M. baccata, M. mandshurica, M. pallasiana, and M. sachalinensis were also confirmed.