Abstract:

The rare and endangered species Primula ranunculoides is endemic to China and is of reasonably high potential horticultural value. The genetic diversity and structure of the species was examined by surveying variation at nine microsatellite loci across 222 individuals sampled from seven natural populations. The results indicated that there was relatively low genetic diversity present within populations (H_e = 0.330, H_o = 0.286) and high genetic differentiation among populations. Levels of population genetic diversity and effective population size were both correlated with plant density, rather than population census size or population area. Gene flow between populations was low (N_m = 0.730) and an AMOVA analysis showed that 48.08% of the total genetic diversity was attributable to among populations and the rest (51.92%) to variation within populations. Bayesian assignment and principal coordinate analyses supported clustering of the seven populations into four groups, which were correlated with topographical features. This suggested that Lianghu Plain (Dongtinghu Plain and Jianghan Plain) and the farming area of Xiushui and Wuning counties were major barriers to gene flow, causing high divergence between different mountain populations. Based on the genetic structure of P. ranunculoides, four management units for conservation purposes are proposed, i.e. the Jiulingshan, Mufushan, Qizimeishan and Yinlu units.

Key words: Primula ranunculoides, genetic diversity, genetic structure, microsatellites, conservation proposal