Genetic diversity and population structure of threatened Calamus species in India: implications for In-situ and Ex-situ conservation

• Published in: Tree genetics & genomes 2024-12, Vol.20 (6), p.39, Article 39
• Main Authors: Sarath, Paremmal, Parveen, Abdul Bari Muneera, VB, Sreekumar, Dasgupta, Modhumita Ghosh, HR, Bohra, Dev, Suma Arun
• Format: Article
• Language: English
• Subjects: Age composition; Biomedical and Life Sciences; Biotechnology; Calamus; Conservation; Ecological niches; Forest products; Forestry; Gene pool; Genetic analysis; Genetic diversity; Genetic markers; Geographical distribution; Global marketing; Heterozygosity; Life Sciences; Microsatellites; Natural populations; Non-timber forest resources; Original Article; Plant Breeding/Biotechnology; Plant Genetics and Genomics; Population decline; Population genetics; Population number; Population structure; Population studies; Populations; Sex; Sex ratio; Species extinction; Threatened species; Tree Biology
• ISSN: 1614-2942; 1614-2950
• DOI: 10.1007/s11295-024-01671-9

Rattans are climbing palms, known for strong flexible canes and are important Non-Timber Forest Products in south and southeast Asian countries. Of the five rattan genera, Calamus holds a pivotal position owing to huge local and global market demand. A substantial part of these NTFPs is harvested from the natural populations, leading many economically exploited rattans to the verge of extinction. The present work intended to study the consequences of population decline on the genetic diversity parameters of four economically exploited threatened Calamus species ( C. brandisii , C. acanthospathus , C. nambariensis and C. andamanicus ) distributed in the three geographical zones of India. The study generated a draft genome of C. brandisii of 848.89 Mb size, which has been used to develop microsatellite markers. Population genetic analysis revealed deviations from Hardy-Weinberg proportions and an excess of heterozygosity, which were interpreted as indicators of small population size combined with obligatory outcrossing, stemming from population decline. Distinct populations with strong genetic structures were identified along with evidence for genetic bottlenecks. The existing ex-situ populations of C. acanthospathus and C. nambariensis have been found inadequate for representing and conserving the available gene pool in the wild. Through MAXENT modeling, highly suitable ecological niche were predicted for C. brandisii . Conservation and management plans, both in-situ and ex-situ need to prioritize the protection of genetically unique populations. In light of the observed sex skewness in rattan populations, augmentation programs should focus on safeguarding mature individuals, enhancing population size and age structure, and monitoring and balancing the sex ratio in wild populations.