In this study, simple sequence repeats (SSRs) specific to marigold were developed using the
inter-SSR technique and a SSR-enriched genomic DNA library. In addition, SSRs derived
from sunflower (Helianthus annuus) were also tested for transferability to marigold. In
total, 38 polymorphic markers with 112 observed alleles were identified in 20 African marigolds
(Tagetes erecta L.) consisting of 14 commercial varieties and six Thai landraces, and
six French marigolds (Tagetes patula L.). The number of alleles per locus ranged from 2 to 7.
The averages of expected and observed heterozygosities were 0.48 and 0.32, respectively.
Polymorphic information content values ranged from 0.10 to 0.71, and resolving power (Rp)
values ranged from 0.23 to 2.77. The SSRs were successfully applied to the differentiation of
the 26 marigold samples into clusters of African commercial varieties, Thai landraces and
French marigold. The genetic relationship analysis revealed that the African commercial varieties
were more closely related to the Thai landraces than to the French marigold. The results
of the study indicate that the SSRs developed are effective for genetic diversity analysis, species
classification and individual identification.