Application of ISSR markers reveals extensive genetic variability in the tropical lycophyte Selaginella ciliaris.

This article focuses on assessing the genetic variability of the tropical lycophyte Selaginella ciliaris using Inter-Simple Sequence Repeat (ISSR) markers. Analyzing 27 samples from diverse humid tropical habitats in Central Java, Indonesia, the study employed three ISSR primers to generate 49 polymorphic loci, revealing 100% polymorphism and exceptionally low pairwise Dice genetic similarity coefficients (0.0000–0.0816). Hierarchical clustering via UPGMA showed no dominant genetic groups but rather multiple small clusters and singletons, indicating pronounced multilocus differentiation and extensive individual-level genetic heterogeneity. The findings demonstrate the effectiveness of ISSR markers as a cost-efficient tool for genetic assessment in non-model tropical plants lacking genomic resources and highlight the high genetic diversity of S. ciliaris as valuable for germplasm screening, conservation planning, and future biotechnological research.