Low diversity in the native populations of Croton tetradenius Baill. when using SNP markers: a future crop with an insecticidal activity

Croton tetradenius Baill. is an aromatic plant species whose essential oils have high economic importance. Its incorporation into Active Germplasm Banks is essential for conservation and future use, yet its genetic variability must be observed. The objective of this study was to estimate the genomic diversity and structure of C. tetradenius in the native populations in the State of Sergipe, Brazil, to include it in the Active Germplasm Bank of Medicinal and Aromatic Plants of the Federal University of Sergipe, using single-nucleotide polymorphism (SNP) markers. A total of 38 plants were collected from four municipalities (Porto da Folha, Poco Redondo, Lagarto, and Pacatuba) in the State of Sergipe. The sequencing of the genomic libraries by genotyping the sequencing of C. tetradenius resulted in the identification of 1387 high-quality SNPs. The average genetic diversity was low (HO < HE = 0.086; I = 0.143; f = 0.099). The analysis of molecular variance revealed a greater genetic variation between the locations (95%), while the genetic differentiation between the locations was low (FST = 0.041–0.062). The discriminant analysis of principal components showed a great overlap of the Lagarto and Poco Redondo plants, indicating that the recent habitat fragmentation may isolate the populations. Based on these results, additional collections from a large number of individuals in the four populations were evaluated. In other regions of occurrence, it will be useful to increase the representation of the existing genetic diversity of C. tetradenius that is now maintained at the Active Germplasm Bank.