Genetic Variability in Natural Populations of Cassia grandis L. F.

ABSTRACT The design of strategies for genetic conservation requires knowledge of the ecologic and genetics aspects of the target species populations. This work aimed to characterize genetically natural populations of Cassia grandis L. F. using isozymes. Genetic diversity was analyzed by allele frequencies ( P ^ i j ) and the following diversity indexes: observed ( H ^ e ) and expected ( H ^ e )average heterozygosity, average number of alleles per locus ( A ^ ) and percentage of polymorphic loci ( P ^); and the genetic structure of populations by Wright's statistics. We estimated gene flow, population effective size and the minimum viable population in the short and long time. The observed results conclude that the studied populations of C. grandis are structured, which can be demonstrated by observation of rare and exclusive alleles, and high genetic diversity among them.摘要 遗传保护策略的制定，需以目标物种种群的生态学与遗传学特征认知为基础。本研究以同工酶（isozymes）为分析手段，对宏伟决明（Cassia grandis L. F.）的天然种群开展遗传特征解析工作。本研究通过等位基因频率（$P^i_j$）以及以下多样性指标量化遗传多样性：观测杂合度（$H^o$）、期望杂合度（$H^e$）、每个位点的平均等位基因数（$A^$）与多态位点百分率（$P^$）；同时借助赖特遗传统计量（Wright's statistics）解析种群遗传结构。此外，本研究还估算了短、长期尺度下的基因流、种群有效规模以及最小可存活种群（minimum viable population）。研究结果表明，本次研究涉及的C. grandis种群存在遗传结构分化，该结论可通过稀有等位基因与特有等位基因的检出，以及种群间较高的遗传多样性得到验证。