ABSTRACT Baru tree (Dipteryx alata) is an arboreal, fruitful plant native to the Cerrado biome with an important socioeconomic impact. Populations of this species are a good model to study anthropogenic disturbances on the biome through the genetic information. In this study, we developed seven new polymorphic microsatellite markers for D. alata, using an enriched genomic library. We performed loci characterization in three populations, obtaining a total of 49 alleles, with an average of 5 to 5.57 alleles per locus. A significant content of polymorphic information was obtained, as indicated by the average expected heterozygosity (uHE), with a total average of 0.58 to 0.65 per locus. The average value of the observed heterozygosity (Ho) was also high, with a total average of 0.73 to 0.85 per locus. Some of the loci are in linkage disequilibrium, such as DalatG6 with DalatB3, DalatH3 and DalatB4. The estimate of the combined loci for the probability of paternity exclusion obtained an average value of 1.00 for all loci, and the average combined probability of identity, the values were (1.210^-5) to (4.410^-6). All markers are informative and suitable for studies on genetic diversity and population structure, aiming at the conservation and management of the species.

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 H O and H E 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.

The pigeonpea [Cajanus cajan (L) Millspaugh] is one of the most important perennial legume crops utilized in the food, fodder, soil conservation, crop-livestock integrated systems, reclaiming of degraded pastures and symbiotic nitrogen fixation. Microsatellite markers were used to estimate the genetic diversity of 77 pigeonpea genotypes selected from the germplasm collections at Embrapa Cattle-Southeast and, to evaluate their transferability to Phaseolus vulgaris and Vigna unguiculata species. The number of alleles per locus ranged from 2 to12, with an average of 5.1 alleles. The PIC values ranged from 0.11 to 0.80 (average 0.49) and the D values from 0.23 to 0.91 (average 0.58). The averages of observed and expected heterozygosity were 0.25 and 0.47, respectively, showing a deficit in heterozygosity. A model-based Bayesian approach implemented in the software STRUCTURE was used to assign genotypes into clusters. A dendrogram was constructed based on the modified Roger's genetic distances using a neighbor-joining method (NJ). A total of four clusters were assembled by STRUCTURE and a strong tendency of correspondence between the Bayesian clusters in the NJ tree was observed. The genetic distance ranged from 0.09 to 0.62 (average 0.37), showing a low genetic diversity in the pigeonpea genotypes. Transferability of pigeonpea-specific microsatellites revealed a cross-amplification and the presence of polymorphic alleles in P. vulgaris and V. unguiculata.

A wide array of molecular markers has been used to investigate the genetic diversity among common bean species. However, the best combination of markers for studying such diversity among common bean cultivars has yet to be determined. Few reports have examined the genetic diversity of the carioca bean, commercially one of the most important common beans in Brazil. In this study, we examined the usefulness of two molecular marker systems (simple sequence repeats - SSRs and amplified fragment length polymorphisms - AFLPs) for assessing the genetic diversity of carioca beans. The amount of information provided by Roger's modified genetic distance was used to analyze SSR data and Jaccards similarity coefficient was used for AFLP data. Seventy SSRs were polymorphic and 20 AFLP primer combinations produced 635 polymorphic bands. Molecular analysis showed that carioca genotypes were quite diverse. AFLPs revealed greater genetic differentiation and variation within the carioca genotypes (Gst = 98% and Fst = 0.83, respectively) than SSRs and provided better resolution for clustering the carioca genotypes. SSRs and AFLPs were both suitable for assessing the genetic diversity of Brazilian carioca genotypes since the number of markers used in each system provided a low coefficient of variation. However, fingerprint profiles were generated faster with AFLPs, making them a better choice for assessing genetic diversity in the carioca germplasm.

O objetivo deste trabalho foi avaliar um conjunto de marcadores microssatélites para identificação e caracterização varietal das cultivares de batata mais amplamente utilizadas no Brasil. O DNA das 14 variedades de batata foi genotipado com marcadores microssatélites, e os alelos foram visualizados em gel de poliacrilamida corado com prata. Vinte e quatro marcadores foram avaliados e apenas um loco foi monomórfico. Com base no padrão de bandas, foi obtido um conjunto com dois microssatélites capazes de identificar e diferenciar todas as cultivares analisadas.

The objective of this work was to evaluate a set of microsatellite markers for varietal identification and characterization of the most widespread potato cultivars in Brazil. The DNA from 14 potato cultivars was genotyped using microsatellite markers and the alleles were scored in silver-stained polyacrylamide gel. Twenty-four microsatellite markers were evaluated, and only one locus was monomorphic. Based on band patterns, a set of two microsatellites that were able to identify and differentiate all examined cultivars was obtained.

O objetivo deste trabalho foi desenvolver novos marcadores microssatélites para feijão-comum. Noventa e nove novos locos de microssatélites foram desenvolvidos a partir de uma biblioteca enriquecida com motivos (CT)8 e (GT)8, proveniente da linhagem CAL-143. A maioria dos microssatélites (51%) esteve relacionada ao metabolismo celular. As demais seqüências estiveram associadas a funções de transcrição. Apenas 17,2% das seqüências apresentaram alguma semelhança com genes de outras espécies.

The objective of this work was to develop new microsatellite markers in common bean. Ninety nine new microsatelitte loci were developed from a microsatellite enriched library for (CT)8 and (GT)8 motifs, from CAL-143 line. The majority of microsatellite sequences (51%) was related to cellular metabolism. The remaining sequences were associated to transcription functions. Only 17.2% of the sequences presented some level of similarity with other plant species genes.

Objetivou-se avaliar o desempenho de híbridos simples de milho (Zea mays L.), obtidos de cruzamentos dialélicos entre linhagens divergentes, estimar a capacidade de combinação das linhagens e verificar se a divergência genética entre as linhagens, obtida por marcadores moleculares, é correlacionada com a heterose dos híbridos simples no campo. Trinta e seis híbridos resultantes de um dialelo parcial foram avaliados em Campinas e em Mococa e as 12 linhagens parentais somente em Campinas, a fim de se calcular a heterose dos híbridos. O delineamento experimental empregado foi o de blocos ao acaso, com três repetições e 2 testemunhas comerciais. Avaliaram-se os caracteres: altura da planta (AP), altura da espiga (AE) e massa de grãos (MG). Análises de variância foram efetuadas, sendo as médias comparadas entre si pelo teste de Tukey a 5%. A capacidade de combinação das linhagens foi obtida de acordo com o método de Geraldi e Miranda Filho. Estimaram-se as correlações entre heterose, produtividade e capacidade específica de combinação com divergência genética obtida por AFLP e SSR. Destacou-se o híbrido PM624 x IP398, e as linhagens VER266 e L105 revelaram efeitos positivos da capacidade de combinação para produtividade. As estimativas de heterose variaram de -559 a 6.320 kg ha-1. Não houve correlação entre heterose, capacidade específica de combinação e produtividade dos híbridos com a distância genética por AFLP e SSR, indicando que não é possível fazer inferências sobre o comportamento dos híbridos de milho a partir da divergência genética entre as linhagens parentais.

The objectives of this research were to evaluate single cross hybrids of maize (Zea mays L.) obtained from partial diallel crosses among contrasting inbred lines, to estimate the combining ability of the lines and to verify whether the genetic diversity among those lines assessed by moleculars markers is correlated with single cross hybrid heterosis Thirty-six single-crosses resulting from partial diallel and the 12 parental lines were evaluated in Campinas, State of São Paulo, in randomized block design, with tree replicates and two commercial checks. The following traits were evaluated: plant and ear height, ear weight and grain weight. Individual variance analysis of hybrids were performed, and the averages were compared by Tukey test (P<0.05). General combining ability of the lines was obtained according to Geraldi e Miranda Filho. Correlations among matrices were estimated through Mantel statistics, considering heterosis, yield and specific combining ability with genetic divergence assessed by AFLP and SSR. The hybrid PM624 x IP398 exhibited outstanding yield capacity and the lines VER266 and L105 showed positive GCA for grain yield. Estimate heterosis ranged from -559 to 6.320 kg ha-1. No significant correlation was observed between heterosis, specific combination ability or grain yield with genetic distance assessed by AFLP and SSR. Therefore, no prediction of hybrids performance could be made on the basis of the genetic divergence of the parent lines.

O objetivo deste trabalho foi avaliar a produtividade de híbridos simples de milho obtidos de cruzamentos dialélicos entre linhagens divergentes, estimar a capacidade de combinação das linhagens e confirmar se a divergência genética entre as linhagens, obtida por marcadores moleculares, é correlacionada com a heterose dos híbridos simples no campo. Trinta e seis híbridos resultantes do dialelo parcial e as 12 linhagens parentais foram avaliadas em Campinas em blocos ao acaso, com três repetições e duas testemunhas. A capacidade de combinação das linhagens foi estimada de acordo com o modelo 4 de Griffing. Estimaram-se a correlação matricial, mediante a estatística de Mantel, entre heterose, produtividade e capacidade específica de combinação com divergência genética por AFLP e SSR. Destacou-se o híbrido PM518 x L111 e as linhagens PM518, IP4035 e L111 apresentaram efeitos positivos da capacidade geral de combinação. As estimativas de heterose variaram de 927 a 6.698 kg ha-1. Houve correlação entre heterose e divergência genética por AFLP e SSR. No entanto, a divergência genética não foi suficiente para determinar a capacidade específica de combinação nem a produtividade dos híbridos.

The objective of this work was to evaluate grain yield of maize single cross hybrids obtained from diallel crosses among contrasting lines, to estimate the combining ability of the lines, and finally to confirm if the genetic diversity among those lines assessed by molecular markers is correlated with single cross hybrids heterosis. The 36 single cross hybrids resulting from partial diallel and 12 parental lines were evaluated in Campinas in randomized block design, with three replicates and two control lines checks. General combining ability of the lines was estimated according to Griffing model 4. Correlations among matrices were estimated through Mantel statistics, considering heterosis, yield and specific combining ability with genetic divergence assessed by AFLP and SSR. The hybrids PM518 x L111 exhibited an outstanding yield and the lines PM518, IP4035 and L111 showed positive general combining ability. The estimate heterosis ranged from 927 to 6,698 kg ha-1. A positive and significant correlation was observed in parental lines between heterosis and genetic diversity assessed by AFLP and SSR. The genetic divergence, however, was not enough to determine the specific combining ability and the hybrids yield.

Vinte locos de marcadores microssatélites foram identificados e caracterizados em feijoeiro. Os microssatélites foram testados em 14 genótipos. O número de alelos variou entre 1 e 3, e o conteúdo informativo de polimorfismo (PIC) entre 0,14 e 0,65. Esses marcadores polimórficos estão disponíveis para serem usados em programas de melhoramento.

Twenty microsatelitte loci were identified and characterized in common bean. Microsatellites were tested in 14 genotypes. The allele number ranged from 1 to 3, and the polymorphism information content (PIC) was between 0.14 and 0.65. These polymorphic markers are available to be used for breeding programs.

The Araucaria angustifolia (Bert.) O. Kuntze, also named the "paraná pine" (‘pinheiro-do-Paraná’ in Portuguese), is a native conifer species naturally occurring in the Brazilian Tropical Atlantic Forest which in Brazil is mostly limited to the southern Brazilian states of Paraná, Santa Catarina and Rio Grande do Sul. Chloroplast DNA markers (cpDNA) are useful in populational genetic studies because of their low substitution rate and the uniparental transmission. The conservation of cpDNA genes between species has allowed the design of consensus chloroplast primers that have had a great impact on population genetics and phylogenetic studies. In this study we used the polymerase chain reaction technique combined with restriction enzyme fragment length polymorphism (PCR-RFLP) to characterize the genetic diversity of the chloroplast genome in nine natural A. angustifolia populations. Among the 141 trees surveyed we found 12 different cpDNA haplotypes and demonstrated that A. angustifolia has high levels of total diversity (hT = 0.612) and an average within-population diversity (hS) of 0.441, suggesting the presence of high within-population variation. The estimated genetic divergence could be helpful in designing breeding programs and species conservation strategies, although additional studies with a larger number of populations and trees is essential for a better understanding of gene flow and the inheritance of major Araucaria angustifolia traits.

A microsatellite marker (SSR) was chosen to simulate a target allele and three criteria (02, 04 and 06 markers per chromosome) were tested to evaluate the most efficient parameters for performing marker-assisted backcross (MAB) selection. We used 53 polymorphic SSRs to genotype 186 BC1 maize (Zea mays L.) plants produced by crossing the inbred maize lines L-08-05 (donor parent) and L-14-4B (recurrent parent). The second backcross (BC2) generation was produced with 180 plants and screened with markers which were not recovered from the first backcross (BC1) generation. A total of 480 plants were evaluated in the third backcross (BC3) generation from which 48 plants were selected for parental genotype recovery. Recurrent genotype recovery averages in three backcross generations were compatible with those expected in BC4 or BC5, indicating genetic gain due to the marker-assisted backcrossing. The target marker (polymorphic microsatellite PHI037) was efficiently transferred. Six markers per chromosome showed a high level of precision for parental estimates at different levels of maize genome saturation and donor alleles were not present in the selected recovered pure lines. Phenotypically, the plants chosen based on this criterion (06 markers per chromosome) were closer to the recurrent parent than any other selected by other criteria (02 or 04 markers per chromosome). This approach allowed the understanding that six microsatellites per chromosome is a more efficient parameter than 02 and 04 markers per chromosome for deriving a marker-assisted backcross (MAB) experiment in three backcross generations.

The objective of this study was to evaluate whether different similarity coefficients used with dominant markers can influence the results of cluster analysis, using eighteen inbred lines of maize from two different populations, BR-105 and BR-106. These were analyzed by AFLP and RAPD markers and eight similarity coefficients were calculated: Jaccard, Sorensen-Dice, Anderberg, Ochiai, Simple-matching, Rogers and Tanimoto, Ochiai II and Russel and Rao. The similarity matrices obtained were compared by the Spearman correlation, cluster analysis with dendrograms (UPGMA, WPGMA, Single Linkage, Complete Linkage and Neighbour-Joining methods), the consensus fork index between all pairs of dendrograms, groups obtained through the Tocher optimization procedure and projection efficiency in a two-dimensional space. The results showed that for almost all methodologies and marker systems, the Jaccard, Sorensen-Dice, Anderberg and Ochiai coefficient showed close results, due to the fact that all of them exclude negative co-occurrences. Significant alterations in the results for the Simple Matching, Rogers and Tanimoto, and Ochiai II coefficients were not observed either, probably due to the fact that they all include negative co-occurrences. The Russel and Rao coefficient presented very different results from the others in almost all the cases studied and should not be used, because it excludes the negative co-occurrences in the numerator and includes them in the denominator of their expression. Due to the fact that the negative co-occurrences do not necessarily mean that the regions of the DNA are identical, the use of coefficients that do not include negative co-occurrences was suggested.

A modified reciprocal recurrent selection (RRS) method, which employed one cycle of high-intensity selection, was applied to two tropical maize (Zea mays L.) populations, BR-105 and BR-106, originating the improved synthetics IG-3 and IG-4, respectively. In the present study the effects of this kind of selection on the genetic structure of these populations and their synthetics were investigated at 30 microsatellite (SSR) loci. A total of 125 alleles were revealed. A reduction in the number of alleles was observed after selection, as well as changes in allele frequencies. In nearly 13% (BR-105) and 7% (BR-106) of the loci evaluated, the changes in allele frequencies were not explained, exclusively due to the effects of genetic drift. The effective population sizes estimated for the synthetics using 30 SSR loci were similar to those theoretically expected after selection. The genetic differentiation (G ST) between the synthetics increased to 77% compared with the original populations. The estimated R ST values, a genetic differentiation measure proper for microsatellite data, were similar to those obtained for G ST. Despite the high level of selection applied, the total gene diversity found in the synthetics allows them to be used in a new RRS cycle.