Using genetic diversity information to establish core collections of Stylosanthes capitata and Stylosanthes macrocephala

Abstract

Stylosanthes species are important forage legumes in tropical and subtropical areas. S. macrocephala and S. capitata germplasm collections that consist of 134 and 192 accessions, respectively, are maintained at the Brazilian Agricultural Research Corporation Cerrados (Embrapa-Cerrados). Polymorphic microsatellite markers were used to assess genetic diversity and population structure with the aim to assemble a core collection. The mean values of HO and HE for S. macrocephala were 0.08 and 0.36, respectively, whereas the means for S. capitata were 0.48 and 0.50, respectively. Roger’s genetic distance varied from 0 to 0.83 for S. macrocephala and from 0 to 0.85 for S. capitata. Analysis with STRUCTURE software distinguished five groups among the S. macrocephala accessions and four groups among those of S. capitata. Nei’s genetic diversity was 27% in S. macrocephala and 11% in S. capitata. Core collections were assembled for both species. For S. macrocephala, all of the allelic diversity was represented by 23 accessions, whereas only 13 accessions were necessary to represent all allelic diversity for S. capitata. The data presented herein evidence the population structure present in the Embrapa-Cerrados germplasm collections of S. macrocephala and S. capitata, which may be useful for breeding programs and germplasm conservation.

Genetic diversity of macaúba fruits from 35 municipalities of the state of Goiás, Brazil

“…For the univariate analyses of variance, there was a significant effect of groups at 5% and 1% probability, and the 5% probability level was found only in the characteristics of percentage of oil in the almond and percentage of oil in the dry fruit (Table 2). This result, according to Santos-Garcia et al (2012), indicates that the clustering analysis was able to classify the municipalities into dissimilarity groups, which ratify their divergences even when the variables are analyzed independently.The group 5 stood out for all the evaluated characteristics. As for group 3, it showed the best average values for almond weight, percentage of oil in the almond and percentage of oil in the dry fruit.…”

Genetic diversity in natural populations of Stylosanthes scabra using ISSR markers

“…The species with autofecudation exhibit greater genetic diversity among the populations (Buzatti et al, 2012), whereas this is different for the plants with high rates of alogamy. In a study by Santos-Garcia et al (2012) with microsatellite markers, S. capitata (which may present alogamia above 20%) did not present a correlation between the genetic distance and the collection sites, although few accesses by collection site were considered by these authors.…”

Genetic diversity of Desmanthus sp accessions using ISSR markers and morphological traits

“…The 25-μL reaction mixtures contained 1X PCR buffer (Invitrogen), 1.5 mM MgCl 2 , 0.8 μM primer, 1 U Platinum Taq DNA Polymerase (Invitrogen), 0.25 μM of each dNTP (Invitrogen), 25 ng DNA template, and sterile distilled water to the total volume of 25 μL. DNA amplifications were performed on thermocycler MJ Reseach, Inc., PTC100 Programmable Thermal Controller (Watertown, USA) under the following conditions: 94°C for 1 min (initial denaturation), followed by 35 cycles of 94°C for 30 s, 55°C for 1 min, and 72°C for 1 min with a final extension step at 72°C for 5 min (Santos-Garcia et al, 2012).…”

“…In the Brazilian Northeast, D. pernambucanus L. Thell predominates (Pengelly and Liu, 2001), which is autogamous (2n = 26 chromosomes), originating in South America, probably in Northeast Brazil (Santos-Garcia et al, 2012). These species are shrub-like, drought resistant, and have a high capacity to obtain nitrogen by association with diazotrophic bacteria, estimating about 30 kg N ha/year coming from biological nitrogen fixation (Freitas et al, 2011).…”