Survey of Genetic Diversity in Ecuadorian Guarango Caesalpinia spinosa (Feuillée ex Molina) Kuntze Assessed via Molecular Markers and Morphology

Caesalpinia spinosa is a native forest tree species of the Andes with growing economic and ecological importance, valued for the high tannin content of its pods, the galactomannans present in the seed endosperm, and its potential for restoration programs and agroforestry systems. In Ecuador, information regarding its genetic and phenotypic diversity has remained limited, thus hindering the establishment of strategies for its conservation and sustainable utilization. In this study, we conducted the first integrated characterization of the Ecuadorian guarango germplasm collection through the evaluation of morphological traits, genetic diversity analysis using SSR and ISSR markers, and spatial assessment of diversity employing the CAPFITOGEN tool. The collection exhibited substantial morphological variability, particularly in traits associated with tree architecture and vegetative vigor, which allowed us to identify differentiated phenotypic groups with non–identical accessions. The molecular exploratory characterization with ISSR markers revealed molecular differentiation among the sampled accessions and complemented the information derived from phenotypic characterization. The integration of morphological, molecular, and spatial datasets provides a preliminary understanding of the genetic diversity present in Ecuador, facilitating the identification of molecularly contrasting accessions and priority areas for future collection campaigns. Overall, these findings serve as a preliminary technical basis to strengthen germplasm management and conservation efforts, as well as to support future domestication and genetic breeding programs for guarango in Ecuador.