RESUMO
In the highlands of Bolivia, native Festuca species are an important source of feed for animals due to their high tolerance to low temperatures and drought. Using simple sequence repeat (SSR) markers developed from expressed sequence tags (ESTs), the genetic diversity of 43 populations of Festuca species from Oruro, La Paz, Potosi and Cochabamba departments was evaluated for the purpose of providing information for effective conservation and breeding. In total, 64 alleles were detected across the 43 populations. SSR locus NFA 142 (with 12 alleles) had the highest number of detected alleles, while locus FES 13 (with eight alleles) had the highest polymorphism information content (PIC) at 0.55. Based on Nei's genetic distance between populations, the unweighted pair group method with arithmetic mean (UPGMA) cluster analysis revealed two major clusters, each consisting of populations from the four departments. However, the analysis of molecular variance (AMOVA) revealed that only 5% of the total variation separated these two groups, indicating low genetic differentiation between the populations. It was also found that there was a low but significant differentiation (0.08%) between the population groups of the four departments (p = 0.01). The newly developed EST-SSR markers are highly valuable for evaluating the genetic diversity of Bolivian fescues and other related species.
Assuntos
Festuca , Variação Genética , Animais , Variação Genética/genética , Festuca/genética , Bolívia , Melhoramento Vegetal , Repetições de Microssatélites/genéticaRESUMO
The western part of South America is a centre of diversity for tomatoes, but genetic diversity studies are lacking for parts of that region, including Bolivia. We used 11 simple sequence repeat (SSR) markers (including seven novel markers) to evaluate genetic diversity and population structure of 28 accessions (four modern cultivars, four advanced lines, nine landraces, 11 wild populations), and to compare their genetic variation against phenotypic traits, geographical origin and altitude. In total, 33 alleles were detected across all loci, with 2-5 alleles per locus. The top three informative SSRs were SLM6-11, LE20592 and TomSatX11-1, with polymorphism information content (PIC) of 0.65, 0.55 and 0.49, respectively. The genetic diversity of Bolivian tomatoes was low, as shown by mean expected heterozygosity (He) of 0.07. Analysis of molecular variance (AMOVA) revealed that 77.3% of the total variation was due to variation between accessions. Significant genetic differentiation was found for geographical origin, cultivation status, fruit shape, fruit size and growth type, each explaining 16-23% of the total variation. Unweighted Pair Group Method with Arithmetic Mean (UPGMA) tree and principal coordinate analysis (PCoA) scatter plot both revealed differentiation between accessions with determinate flowers and accessions with indeterminate flowers, regardless of cultivation status. The genetic profiles of the accessions suggest that the Bolivian tomato gene pool comprises both strictly self-pollinating and open-pollinating genotypes.
Assuntos
Solanum lycopersicum , Bolívia , Variação Genética/genética , Solanum lycopersicum/genética , Repetições de Microssatélites/genética , Polimorfismo GenéticoRESUMO
Coffea arabica L. (arabica coffee), the only tetraploid species in the genus Coffea, represents the majority of the world's coffee production and has a significant contribution to Nicaragua's economy. The present paper was conducted to determine the genetic diversity of arabica coffee in Nicaragua for its conservation and breeding values. Twenty-six populations that represent eight varieties in Nicaragua were investigated using simple sequence repeat (SSR) markers. A total of 24 alleles were obtained from the 12 loci investigated across 260 individual plants. The total Nei's gene diversity (H(T)) and the within-population gene diversity (H(S)) were 0.35 and 0.29, respectively, which is comparable with that previously reported from other countries and regions. Among the varieties, the highest diversity was recorded in the variety Catimor. Analysis of variance (AMOVA) revealed that about 87% of the total genetic variation was found within populations and the remaining 13% differentiate the populations (F(ST) = 0.13; P < 0.001). The variation among the varieties was also significant. The genetic variation in Nicaraguan coffee is significant enough to be used in the breeding programs, and most of this variation can be conserved through ex situ conservation of a low number of populations from each variety.