Abstract:

A total of 398 014 bp long terminal repeat retrotransposons（LTR-RT）were found in the genomic sequence of Vaccinium macrocarpon‘Ben Lear’，accounting for 11.17% of the whole genome，among which 228 Ty1-Copia family members and 137 Ty3-Gypsy family members were identified in all LTR-RTs. Fifty-three primers were developed based on LTR-RT insertion polymorphisms. Using 45 blueberry cultivars and one cranberry cultivar，17 pairs of polymorphic primers were screened and retrotransposon-based insertion polymorphism（RBIP）system of blueberry was established. Phylogenetic analyses and molecular identity of 46 germplasms were performed using RBIP markers. The locus with the highest polymorphism was Vmrg1，the lowest locus was Vmrg14. The size of PCR products varied from 200 bp to 463 bp，and the minimum and maximum length products were found at loci Vmrc19 and Vmrc3，respectively. All the cultivars were clustered into six groups in the phylogenetic tree. GroupⅠwas comprised of three northern highbush blueberries while cranberry was clustered into group Ⅵ. Other four groups included northern highbush blueberries，southern highbush blueberries and/or rabbiteye blueberries. Molecular identity of 45 blueberry cultivars and one cranberry cultivar were constructed using“1”and“0”strings obtained from 17 polymorphic loci，which provided references for identification of bluberry cultivars.

Key words: blueberry, retrotransposon, molecular marker, genetic relationship, cultivar identification