Dardengo Juliana de Freitas Encinas, Rossi Ana Aparecida Bandini, da Silva Bruna Mezzalira, da Silva Ivone Vieira, da Silva Carolina Joana, Sebbenn Alexandre Magno
Rev Biol Trop. 2016 Sep;64(3):1091-9. doi: 10.15517/rbt.v64i3.21461.
The quantification of genetic diversity and intrapopulation spatial genetic structure (SGS) of tree species are important aspects for in and ex situ conservation practices. In this study we seek to understand the importance of conservation areas by quantifying the genetic diversity and the spatial genetic structure of a natural population of Theobroma speciosum. Within this population, 49 adults and 51 subadults were genotyped for five microsatellite loci. The results showed that adults and subadults have similar levels of genetic diversity and inbreeding (adults: A= 10.4, Ae = 10.3, F= 0.68, subadults: A= 10.6, Ae= 10.6, F= 0.57). Genetic diversity was spatially structured within the population, and the results suggest that near-neighbor trees up to a distance of 70 m are likely related. SGS is likely the result of short-distance seed dispersal, the short-distance range of pollinators, and infrequent breaches of the self-incompatible mating system. Considering the high demographic density of the species and size of the study area, as well as the high average number of alleles per locus and the presence of rare alleles, we believe that the study population is an excellent resource for in situ genetic conservation of T. speciosum. The study area is also a useful resource for collecting germplasm for ex situ conservation and seed collection, either for breeding programs used in the restoration of degraded areas or forest improvement.
对树种的遗传多样性和种群内空间遗传结构（SGS）进行量化，是迁地和就地保护实践的重要方面。在本研究中，我们试图通过量化特种可可树自然种群的遗传多样性和空间遗传结构，来了解保护区的重要性。在该种群中，对49株成年树和51株亚成年树的5个微卫星位点进行了基因分型。结果表明，成年树和亚成年树具有相似的遗传多样性和近亲繁殖水平（成年树：A = 10.4，Ae = 10.3，F = 0.68；亚成年树：A = 10.6，Ae = 10.6，F = 0.57）。种群内的遗传多样性具有空间结构，结果表明距离达70米的近邻树木可能具有亲缘关系。SGS可能是短距离种子传播、传粉者短距离活动范围以及自交不亲和交配系统很少被打破的结果。考虑到该物种的高种群密度、研究区域的大小，以及每个位点的平均等位基因数较高和稀有等位基因的存在，我们认为该研究种群是特种可可树就地遗传保护的优质资源。该研究区域也是收集种质用于迁地保护和种子采集的有用资源，可用于退化地区恢复或森林改良的育种计划。
