Information on the genetic diversity and population structure is essential for developing conservational management programs, especially for threatened species. Decalepis salicifolia (Bedd. ex Hook.f.) Venter is a steno-endemic and critically endangered species of the south Western Ghats of India. The present study used ISSR markers as well as essential oil profiling to reveal the extent and distribution of genetic as well as the chemical diversity of all the twelve known populations of D. salicifolia. A total of 84 amplicons generated using 17 ISSR primers represented an overall 72.34% polymorphism. The highest percentage of polymorphic loci was recorded in the population of Theemalai (40.48%) and lowest in Kokanmalai (4.76%) with an average of 20.04% across all the studied populations. At the species level, the Nei’s genetic diversity observed was 0.255 ± 0.186, while Shannon’s information index observed was 0.385 ± 0.260. The genetic similarity-based unweighted pair-group method with arithmetic average dendrogram grouped the populations according to their geographic locations, which was corroborated by principal component analysis and Bayesian clustering. Distribution of genetic variance through analysis of molecular variance indicated that 38% variance resides within the population, and 62% variance resides among the populations (P < 0.001). Gas chromatography analyses of root volatiles showed significant variation in the percent content of 2-hydroxy-4-methoxybenzaldehyde. The Mantel test analyses showed a positive correlation between the genetic versus geographic distances. Based on the results, both ex situ and in situ conservation strategies are suggested to maximally preserve the genetic resources of this endangered species.

中文翻译：

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人口遗传学耦合化学分析对印度小Dec（Decalepis salicifolia）（Bedd。ex Hook.f.）Venter的保护意义，Venter是印度西高止山脉的一种地方性和极度濒危物种。

关于遗传多样性和种群结构的信息对于制定保护管理计划，特别是对受威胁物种而言至关重要。Decalepis salicifolia（Bedd。ex Hook.f.）Venter是印度西南高止山脉的一种稀有动物，极度濒危。本研究使用ISSR标记和精油分析来揭示所有12个已知的D. salicifolia种群的遗传和化学多样性的程度和分布。使用17个ISSR引物产生的总共84个扩增子代表总体72.34％多态性。在Theemalai人群中记录的多态位点百分比最高（40.48％），在Kokanmalai中最低（4.76％），在所有研究人群中平均为20.04％。在物种水平上，观察到的Nei遗传多样性为0.255±0.186，而Shannon的信息指数为0.385±0.260。基于算术平均树状图的基于遗传相似性的非加权成对组方法根据人口的地理位置将其分组，这通过主成分分析和贝叶斯聚类得到了证实。通过分子变异分析得出的遗传变异分布表明，种群内部存在38％的变异，种群之间存在62％的变异（P  <0.001）。根挥发物的气相色谱分析表明2-羟基-4-甲氧基苯甲醛的百分比含量存在显着变化。Mantel测试分析显示遗传距离与地理距离之间呈正相关。根据结果​​，提出了非原生境和原生境保护策略，以最大限度地保护这一濒危物种的遗传资源。