Sequence-related amplified polymorphism (SRAP) markers were used to investigate the genetic diversity among 30 populations of Toona ciliata Roem. sampled from the species' distribution area in China. To analyze the polymorphism in the SRAP profiles, 1505 primer pairs were screened and 24 selected. A total of 656 SRAP bands ranging from 100 to 1500 bp were acquired, of these 505 bands (77%) were polymorphic. The polymorphism information content (PIC) values ranged from 0.32 to 0.45, with an average of 0.41. An analysis of molecular variance (AMOVA) indicated that the most significant variation was attributable to differences among the populations and that variation within the populations was OPEN ACCESSForests 2015, 6 1095 small. STRUCTURE analysis divided the 30 populations into two parts. The unweighted pair group method of arithmetic averages (UPGMA) clustering and principal coordinates analysis (PCoA) showed that the 30 populations could be classified into four types. The results demonstrate a clear geographical trend for T. ciliata in China and provide a theoretical basis for future breeding and conservation strategy of T. ciliata.

Toona ciliata (Meliaceae) is a rare, fast-growing commercial tree species that produces red timber with beautiful grains. It used to be widely distributed in the past, but few natural forests exist in the field now. Here, we tested 12 nuclear microsatellite markers derived from 551 individuals of 29 populations in China, and investigated the genetic diversity and population structure in T. ciliata. Our results revealed 146 alleles obtained from all of the populations studied here, with an average polymorphic information content of 0.723. The populations could be divided into two major genetic lineages using STRUTURE analysis: 14 and 15 populations from different provinces clustered in Western and Eastern genetic lineages, respectively. The genetic differentiation among the two genetic lineages was 28%. The genetic diversity of the Western lineage was higher than that of the Eastern lineage. Moreover, a Mantel test of the relationship between genetic and geographic distances revealed significantly positive correlations both among all 29 populations and within the Eastern genetic lineage, whereas there was no significant correlation in the Western genetic lineage. Therefore, in the conservation strategy of T. ciliatare sources, the two genetic lineages should be treated independently. To the best of our knowledge, these data are the first detailed characterization of the genetic structure and diversity of T. ciliata populations using nuclear microsatellite markers. The obtained results lay the foundation for preservation of the T. ciliata germplasm resources and support further artificial breeding efforts.

The small abalone Haliotis diversicolor is an economically important shellfish species in southern China. Wild (Japanese, Guangdong, and Hainan) and cultured (Taiwanese and Vietnamese) subpopulations of small abalone were examined using seven microsatellite loci to assess the levels of genetic diversity and the degree of genetic differentiation among them. These seven microsatellite markers showed a high level of polymorphism. A total of 209 alleles were detected, with an average of 29.86 alleles per locus among the five subpopulations. The average observed heterozygosities per locus ranged from 0.733 in the Japanese subpopulation to 0.804 in the Hainan subpopulation, while the average expected heterozygosities per locus ranged from 0.909 in the Vietnamese subpopulation to 0.940 in the Guangdong subpopulation. Values for the differentiation index D est varied from 0.1071 to 0.4020 among different subpopulations. The values for genetic distance (D A) ranged from 0.244 to 0.409, with an average of 0.294. Both D est and D A showed that the largest distance was between the Japanese and Vietnamese subpopulations. Principal coordinate analysis was performed for all subpopulations and loci using genetic distance to summarize genetic relationships. The analysis indicated a grouping of the three wild subpopulations (Japanese, Guangdong, and Hainan). The Vietnamese subpopulation was plotted separately from others. The information on the genetic variation and differentiation in the wild and cultured subpopulations obtained in this study is useful for the development of guidelines for genetic breeding programs for small abalone.

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