Objective Genetic diversity and relationship of 170 varieties of Gerbera jamesonii Bolus were determined applying EST-SSR markers for evaluating, conserving, and utilizing the newly introduced germplasms.

Method  Using one to three pairs of EST-SSR primers with high polymorphism and clear bands for each chromosome pair in the plants, DNA from 6 G. jamesonii populations were amplified by PCR. Based upon SSR polymorphism, differentiation, uniformity, and UPGMA clusters, the diversity and phylogenetic relation of the cultivars were determined.

Results  In 39 selected EST-SSR primers, 168 alleles (Na) averaging 4.308 each were detected showing an average Shannon information index (I) of 1.098 and variation of polymorphism information content (PIC) of 0.760 (i.e., higher than the benchmark, 0.5) ranging 0.431-0.920. The average numbers of alleles, genotypes, and Na as well as the degree of heterozygosity, mixing, and genetic diversity were all higher in the Yunnan population than the others. The genetic distances were 0.069 on average between the 6 populations that ranged 0.016-0.158 with an average consistency of 0.935 ranging 0.854-0.984. The shortest distance was found between the Yunnan and the mixed populations, and the longest between the German and the Japanese. The closely related German, Yunnan, and mixed populations were clustered in one category, as the entire collection of the 170 germplasms in Groups I, II, III, IV, V, and VI at the genetic similarity coefficient of 0.550. At the coefficient of 0.558, Group V was divided into 4 subgroups; and at the coefficient of 0.570, Group VI into 4 subgroups. The distribution was relatively simplistic rather than dispersed in same potting, pasta or bubble type.

Conclusion  The highly polymorphic EST-SSR markers selected in this study could satisfactorily unveil the diversity and relationship of 170 genetically significantly differentiated G. jamesonii germplasms.