Genetic Diversity Analysis in Natural Chinese Holly Using ISSR and SCoT Markers

The Chinese holly (Ilex chinensis Sims.), an evergreen tree species native to China, is distributed mainly in regions south of the Qinling Mountains and Huai River. This research aimed to characterize the molecular profiles and genetic relationships of 40 Chinese holly genotypes via inter-simple sequence repeat (ISSR) and start codon targeted (SCoT) polymorphism markers. Genetic diversity analysis revealed that the ISSR markers detected 111 polymorphic bands from 13 primers, with a polymorphism rate of 88.10%. The analysis generated parameters such as the observed allele number (Na = 1.876), effective allele number (Ne = 1.461), Shannon’s information index (I = 0.271), and expected heterozygosity (H = 0.411). In comparison, the SCoT markers produced 65 polymorphic bands from the 6 primers, resulting in a 100% polymorphism rate, with Na = 2.000, Ne = 1.695, I = 0.393, and H = 0.575. Cluster analysis classified the 40 genotypes into two main clusters with genetic similarity coefficients of 0.69 (ISSR) and 0.55 (SCoT). The ISSR markers presented the greatest similarity between the ZSS and ZLS genotypes, whereas the ZZDH and ZWW genotypes presented lower similarity. Conversely, the SCoT markers identified ZZP and ZJDS as the most similar, with ZLJ and ZHX showing less similarity. These results provide a theoretical basis for hybrid breeding, germplasm innovation, and conservation strategies of Chinese holly in China.