Chin J Plant Ecol ›› 2008, Vol. 32 ›› Issue (1): 143-151.DOI: 10.3773/j.issn.1005-264x.2008.01.016

• Research Articles • Previous Articles     Next Articles

GENETIC DIFFERENTIATION OF QUANTITATIVE TRAITS AND LOCAL ADAPTABILITY OF REMNANT POPULATIONS OF ISOETES SINENSIS AND IMPLICATIONS FOR CONSERVATION AND GENETIC REINFORCEMENT

YANG Wei, YE Qi-Gang, LI Zuo-Zhou, HUANG Hong-Wen*()   

  1. Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan 430074, China
  • Received:2006-04-12 Accepted:2006-07-31 Online:2008-01-30 Published:2008-01-30
  • Contact: HUANG Hong-Wen

Abstract:

Aims Isoetes sinensis (Isoeteaceae) is a critically endangered aquatic fern ally in China. Understanding the genetic differentiation of quantitative traits and local adaptation of the remnant populations should provide insight into the adaptation of different populations to their local environment and useful information for formulating appropriate conservation strategy.
Methods The quantitative traits of nine isozyme multilocus genotypes from three remnant populations of I. sinensis were investigated using nested analysis based on random block design in common-garden experiments. Population differentiation of allozyme (FST) and quantitative traits (QST) were estimated using the Bayesian approach.
Important findings Of 14 quantitative traits examined, ten were found to be significantly different among populations and three were significantly different within populations. Multiple comparison by Turkey tests indicated that the mean values of five traits were the highest for the Songyang population and lowest for the Xiuning population, whereas the mean values of the macrosporangium characteristics and plant height were highest for the Jiande population and lowest for the Xiuning population. This result probably reflected different scenarios of founder effect, habitat competition ability and trade-off between vegetative and reproductive growth. Local adaptation was evaluated as a difference of QST vs. FST value, and eight important reproductive fitness traits were found to be significant (QST>FST, p≤0.05 ) under the selfing assumption, suggesting local adaptability in the remnant populations. It is more likely that there is a potential risk of outbreeding depression if genetic enhancement is implemented by translocation of individuals from different populations. Therefore, translocation among these remnant populations is not recommended. Instead, we recommend increasing gene flow within each population and improving habitat management by reducing competition with companion species in in situ conservation for Xiuning and Songyang populations. In the case of Jiande population, minimizing human disturbance should be considered as a top priority and an in situ conservation plot should be designated for the population.

Key words: Isoetes sinensis, genetic differentiation, quantitative traits, genotype, local adaptation, conservation strategy, genetic reinforcement