Genetic diversity of Brazilian Pantaneiro horse and relationships among horse breeds

The objective of this work was to evaluate the genetic diversity of Brazilian Pantaneiro horse by microsatellite markers, investigate the effect of genetic bottlenecks and estimate genetic differentiation among four horse breeds. Genetic variation was estimated through allele frequencies and mean breed heterozygosity. Nei's genetic distances among the breeds Pantaneiro, Thoroughbred, Arabian, Spanish Pure Breed (Andalusian), and Uruguay Creole were calculated, and it was used to construct an UPGMA dendrogram. Clustering at different K values was calculated to infer population structure and assign individuals to populations. Nei's distances showed a minimum distance between Pantaneiro horse and Spanish Pure Breed (0.228), and similar distances from Spanish Pure Breed to Thoroughbred and to Arabian (0.355 and 0.332). It was observed a great level of diversity, clear distance from Pantaneiro horse to other breeds, and genetic uniformity within breed. It was verified a certain level of substructure of Pantaneiro horse showing no influences from the other studied breeds.

Divergence and genetic variability among superior rubber tree genotypes

The objective of this work was to estimate the genetic variability and divergence among 22 superior rubber tree (Hevea sp.) genotypes of the IAC 400 series. Univariate and multivariate analyses were performed using eight quantitative traits (descriptors), including yield. In the univariate analyses, the estimated parameters were: genetic and environmental variances; genetic and environmental coefficients of variation; and the variation index. The Mahalanobis generalized distance, the Tocher agglomerative method and canonical variables were used for the multivariate analyses. In the univariate analyses, variability was verified among the genotypes for all the variables evaluated. The Tocher method grouped the genotypes into 11 clusters of dissimilarity. The first four canonical variables explained 87.93% of the cumulative variation. The highest genetic variability was found in rubber yield-related traits, which contributed the most to the genetic divergence. The most divergent pairs of genotypes are suggested for crossbreeding. The genotypes evaluated are suitable for breeding and may be used to continue the IAC rubber tree breeding program.

Phytogeographical origin of Madeiran common beans based on phaseolin patterns

The objective of this work was to determine the geographic origin of the Madeiran common bean (Phaseolus vulgaris) gene pool. Phaseolin patterns of 50 accessions representing the diversity of common bean collected in Madeira, Portugal, and conserved in the ISOPlexis Germplasm Bank, were analysed using the Experion automated electrophoresis system, based on lab-on-a-chip technology. Five common bean standard varieties with typical phaseolin patterns were used to determine the phytogeographical origin of the Madeiran common bean accessions. Ninety two percent of the accessions exhibited a phaseolin pattern consistent with the one of common bean types belonging to the Andean gene pool, while the origin of the remaining 8% of the accessions was indistinguishable. The application of a similarity coefficient of 85%, based on Pearson correlations, increases the number of accessions with uncertain pattern. The analytical approach used permitted the determination of the origin of the common bean gene pool, which is Andean in 98% of the cases, and clustering of the observed variability among the Madeiran common beans.

Genetic diversity of cultivated accessions and wild species of rubber tree using EST‑SSR markers

The objective of this work was to evaluate the efficiency of EST‑SSR markers in the assessment of the genetic diversity of rubber tree genotypes (Hevea brasiliensis) and to verify the transferability of these markers for wild species of Hevea. Forty‑five rubber tree accessions from the Instituto Agronômico (Campinas, SP, Brazil) and six wild species were used. Information provided by modified Roger's genetic distance were used to analyze EST‑SSR data. UPGMA clustering divided the samples into two major groups with high genetic differentiation, while the software Structure distributed the 51 clones into eight groups. A parallel could be established between both clustering analyses. The 30 polymorphic EST‑SSRs showed from two to ten alleles and were efficient in amplifying the six wild species. Functional EST‑SSR microsatellites are efficient in evaluating the genetic diversity among rubber tree clones and can be used to translate the genetic differences among cultivars and to fingerprint closely related materials. The accessions from the Instituto Agronômico show high genetic diversity. The EST‑SSR markers, developed from Hevea brasiliensis, show transferability and are able to amplify other species of Hevea.

Genetic diversity between improved banana diploids using canonical variables and the Ward-MLM method

The objective of this work was to estimate the genetic diversity of improved banana diploids using data from quantitative analysis and from simple sequence repeats (SSR) marker, simultaneously. The experiment was carried out with 33 diploids, in an augmented block design with 30 regular treatments and three common ones. Eighteen agronomic characteristics and 20 SSR primers were used. The agronomic characteristics and the SSR were analyzed simultaneously by the Ward-MLM, cluster, and IML procedures. The Ward clustering method considered the combined matrix obtained by the Gower algorithm. The Ward-MLM procedure identified three ideal groups (G1, G2, and G3) based on pseudo-F and pseudo-t² statistics. The dendrogram showed relative similarity between the G1 genotypes, justified by genealogy. In G2, 'Calcutta 4' appears in 62% of the genealogies. Similar behavior was observed in G3, in which the 028003-01 diploid is the male parent of the 086079-10 and 042079-06 genotypes. The method with canonical variables had greater discriminatory power than Ward-MLM. Although reduced, the genetic variability available is sufficient to be used in the development of new hybrids.

Genetic associations in the detection of QTLs for wheat spike-related traits

The objective of this work was to assess the genetic diversity and population structure of wheat genotypes, to detect significant and stable genetic associations, as well as to evaluate the efficiency of statistical models to identify chromosome regions responsible for the expression of spike-related traits. Eight important spike characteristics were measured during five growing seasons in Serbia. A set of 30 microsatellite markers positioned near important agronomic loci was used to evaluate genetic diversity, resulting in a total of 349 alleles. The marker-trait associations were analyzed using the general linear and mixed linear models. The results obtained for number of allelic variants per locus (11.5), average polymorphic information content value (0.68), and average gene diversity (0.722) showed that the exceptional level of polymorphism in the genotypes is the main requirement for association studies. The population structure estimated by model-based clustering distributed the genotypes into six subpopulations according to log probability of data. Significant and stable associations were detected on chromosomes 1B, 2A, 2B, 2D, and 6D, which explained from 4.7 to 40.7% of total phenotypic variations. The general linear model identified a significantly larger number of marker-trait associations (192) than the mixed linear model (76). The mixed linear model identified nine markers associated to six traits.

Genetic dissimilarity among jabuticaba trees native to southwestern Paraná, Brazil

Knowledge on the genetic diversity within and between genotype groups is of great importance for breeding programs. The purpose of this study was to estimate the genetic dissimilarity among 36 native jabuticaba trees (Plinia cauliflora) from five sites in the southwestern region of Paraná, Brazil. Sixteen fruit traits were analyzed, based on multivariate techniques (canonical variables, Tocher and UPGMA), using Mahalanobis' distance as dissimilarity measure. By the techniques of clustering and graphic dispersion, together with the comparison of means, the genetic diversity among native jabuticaba trees was efficiently identified, indicating a high potential of these genotypes for breeding programs. The traits of greatest importance for dissimilarity were percentage of pulp and of skin, which are easily measured. The clustering structure is related to the collection sites and for breeding programs, genotypes from different sites should be crossed to generate progenies to be tested. Genotypes 'CV5' and 'VT3' should be conserved in genebanks, due to its important agronomic traits.

Molecular characterization of papaya genotypes using AFLP markers

Due to the low genetic variability reported in the commercial plantations of papaya (Carica papaya L.), the objective of this study was analyze the genetic diversity of 32 genotypes including cultivars, landraces, inbred lines, and improved germplasm using the AFLP technique (Amplified Fragment Length Polymorphism). The genetic distance matrix was obtained using the Nei and Li genetic distance and clustering was performed using the unweighted pair-method with arithmetic mean (UPGMA). Using 11 combinations of EcoRI/MseI primers, 383 polymorphic bands were obtained. On average, 34.8 polymorphic bands were obtained per primer combination. Five clusters were formed. The traditional cultivar 'Sunrise' and the inbred line CMF-L30-08 were the closest genotypes, and the improved germplasm (CMF041) and landrace (CMF233) the most distant. The main papaya cultivars commercially grown in Brazil, as well as four inbred lines and three improved germplasm, were clustered together, however, were not grouped in the same branch. The genetic distance between the Sunrise and Golden cultivars was 0.329, and even arising from mutation and selection within the Sunrise variety, the Golden stores considerable genetic variability. Additional variability was observed in the inbred lines derived from papaya breeding program at Embrapa Cassava and Fruits.

An overview on the Brazilian orange juice production chain

Brazil is the world's largest producer of oranges and uses more than 70% of the harvested fruits in the production of juices. The amount of processed orange is growing about 10% per year, confirming the trend of the Brazilian citrus for juice production. This research aimed to investigate the Brazilian orange juice production chain from 2005 to 2009. Data from the amount of frozen juice produced and exported, international price of orange juice, and intermediate transactions were assessed in order to make possible selection of all interveners involved in the chain. The study using the Social Network Analysis (SNA) showed that the densest relationships in the network are from exporters to importers and from orange growers to the orange processing industry. No difference was found in the values of the network geodesic distance or the clustering coefficients from 2005 to 2009. The degree of centrality increased steadily throughout the years indicating that the processing industry attempts to minimize the risks by centralizing the actions. A decrease in export of orange juice from 2007 (2.07 10(6) t) to 2008 (2.05 10(6) t) was found, probably due to the world's financial crisis with recovery in 2009. Since 2004, there has been an increase of nearly 10% per year in the market preference of concentrate juice (OFCJ) when compared to the "not from concentrated" juice (NFC). Nowadays the NFC market represents nearly 50% of all Brazilian export which impacted in the logistic distribution and transportation issues.