Genetic Diversities and Relationships of 9 Introduced Species/Cultivars of Quercus by ISSR Molecular Markers

In October 2017, Quercus palustris ‘Pin Oak’, Q. coocinea ‘Scarlet Oak’, Q. palustris ‘Pacific Brilliance’, Q. icolor ‘Swamp White Oak’, Q. rubra ‘Red Oak’, Q. palustris ‘Green Pillar’ were introduced from Haining, Zhejiang province, and in November 2017, 5-year seedlings of Q. phellos and two Q. nuttallii germplasms (red leaves and green leaves) were introduced from Changsha, Hunan province, Ningbo, Zhejiang province. In May 2018, leaves of above introduced plants were collected for genomic DNA extract. Genetic diversities, genetic relationships were analyzed by UPGMA dendrogram and ISSR molecular markers. The results showed that 23 polymorphic primers were selected from 26 ones for ISSR, and 298 polymorphic bands accounting for 93.42% of the total bands were obtained by PCR amplification. The genetic similarity coefficients of species and cultivars of Quercus varied from 0.485 9 to 0.764 9. UPGMA dendrogram showed that there were different genetic relations among tested species and cultivars. They could be divided into 3 groups at the genetic similarity coefficient of 0.650, among which Q. palustris ‘Green pillar’, Q. palustris ‘Pacific Brilliance’ and Q. palustris ‘Pin Oak’ and two Q. nuttallii germplasm were in Group I, Q. phellos, Q. coocinea ‘Scarlet Oak’ and Q. rubra ‘Red Oak’ were in group II, while Q. icolor ‘Swamp White Oak’ in group III. The relationship between Q. palustris ‘Green pillar’ and Q. palustris ‘Pacific Brilliance’ was the closest, because of the same species, while the relationships between Q. icolor ‘Swamp White Oak’ and the other 8 species/culitvars were the farthest.