Assignment of genotypes to populations and assessment of genetic diversity of Tecomella undulata trees of Rajasthan (India) using ISSR markers

摘要

© 2021, Society for Plant Research.Tecomella undulata (Sm.) Seem (Bignoniaceae) is an important timber yielding tree species of arid region. It is one of the most dwindling species of Rajasthan (India) which is represented by its fragmented populations. Its population is drastically reduced due its over-exploitation for wood and medicinal use. Knowledge of the natural genetic variation and population structure is an important step for developing an appropriate conservation strategy for the species. For the present study, population structure of the species was investigated using ISSR markers by taking 120 individuals from 12 populations covering the potential pockets of arid state of Rajasthan. The sampled populations harbored high level of genetic diversity as assessed through ISSR markers (H = 0.1646, I = 0.2790) that was partitioned more within the populations (58) than in between the populations (42). The results of STRUCTURE and split decomposition analysis revealed the existence of two admixed genetic pools of the species in Rajasthan. The pairwise Nei’s gene distance among the populations demonstrated a narrow range from 0.0028 to 0.213. The isolation by distance analysis carried out through the Mantel test demonstrated that the species witnessed a weak correlation (r2 = 0.010, P = 0.170) among the genetic and geographic distance. Our results suggest that the narrowly distributed Tecomella undulata populations in Rajasthan demonstrated high genetic diversity within the populations, however overall population structure is weak.