Flávio de França Souza

Comparative study of different molecular markers for classifying and establishing genetic relationships in Coffea canephora

The genetic variability characterization of the accessions of the germplasm collection, using molecular markers, is being applied as a complementary strategy to the traditional approaches to redefine the plant genetic resources. In this study, we compared the informativeness and efficiency of the molecular markers RAPD, AFLP and SSR in the analysis of 94 accessions of Coffea canephora germplasm held by the breeding program of the Brazilian Agricultural Research Corporation (Embrapa), Rondônia State, Brazil. For this, we considered the marker’s discriminatory power and level of polymorphism detected and also the genetic relationships and clustering (dendrogram) analysis. The RAPD marker yielded low-quality data and problems in the discrimination of some accessions, being less recommended for genetic studies of C. canephora. The SSRs had a higher level of information content and yielded high-quality data, while AFLP was the most efficient marker system because of the simultaneous detection of abundant polymorphism markers per few reactions. Our results indicate that AFLP and SSR, allies to the intrinsic characteristics of each technique, are the most suitable molecular markers for genetic studies of C. canephora. However, the choice of AFLP or SSR in the species characterization should be made in agreement with some characteristics that are discussed in this work.

Molecular diversity in Coffea canephora germplasm conserved and cultivated in Brazil

This work aimed to characterize accessions that represent the C. canephora germplasm conserved and cultivated in Brazil. A total of 130 accessions from germplasm banks of IAC (Sao Paulo), UFV (Minas Gerais) and also collected in plantations of the State of Espirito Santo and Rondonia were evaluated with a set of 20 new microsatellite primers. Multivariate methods were used to estimate the relationship among the accessions. High level of polymorphism and two major diversity clusters were identified. First cluster was composed by the accessions conserved in the IAC and UFV collections and the second was formed by accessions collected in areas under cultivation. Accessions from Espirito Santo and Rondonia were clear separated, composing two subclusters. Despite the great polymorphism found in Brazilian plantations, the diversity may be increased, because a new threshold in the genetic gains is expected on breeding programs with the intensification of the use of conserved germplasm.

Avaliação de caracteres morfológicos úteis na identificação de plantas poliplóides de melancia

The quantitative variation of the morphological characters in diploid, triploid and tetraploid genotypes of watermelon [Citrullus lanatus (Thunb.) Matsum. & Nakai] was evaluated in three diploids, three tetraploids and three triploids hybrids, in relation to the number of chloroplasts per leaf stomata (NCF); width and length of the leaves (LFH e CFH); leaf width/length ratio (LF/CF); stem diameter (DCE); petal diameter in male and female flowers (DCM and DCF); ovary diameter (DOV); fruit weight (PMF); transversal and axial fruit diameter (DTF and DLF); fruit diameter axial/diameter transversal ratio (DL/DT) and rind thickness (EMC). A randomized block design was employed with three replications and five plants per plot. A nested analysis was performed and the ploidy level was considered the main factor. The genotypes were clustered at a dendrogram based on generalized Mahalanobis distance and also plotted on Cartesian plain using scores of the first and second canonic variables. Relative contribution of the variables to clustering was estimated by the Singh Method and the matrix of correlation was obtained using the Principal Component Analysis. The NCF presented higher relative importance (41%) to set divergence clusters, while DCF, DCM, DOV and DT/DL when analyzed together showed themselves efficient to discriminate diploids, triploids and tetraploid plants. So, they are recommended to aid watermelon breeding programs to obtain polyploid plants.

Preliminary characterization of Psidium germplasm in different Brazilian ecogeographic regions

O objetivo deste trabalho foi caracterizar 119 acessos de goiabeira e 40 acessos de aracazeiro identificados em 35 ecorregioes brasileiras, de acordo com descritores da International Union for the Protection of New Varieties of Plants (UPOV). A maioria dos acessos de aracazeiro apresentou grandes espacos entre as nervuras da folha, enquanto os de goiabeira apresentaram espacos pequenos. Os frutos de aracazeiro foram classificados como pequenos, enquanto os de goiabeira apresentaram tamanho de medio a grande. A maioria dos acessos de aracazeiro (91%) apresentou cor branca para a polpa do fruto, enquanto 58% dos de goiabeira apresentaram cor de rosa-claro a rosa-escuro. As diferencas nos frutos entre Psidium selvagens e domesticados indicam que os frutos foram os mais alterados pela selecao artificial.

Divergência genética entre variedades de videiras do Banco Ativo de Germoplasma da Embrapa Semiárido

Este trabalho teve por objetivo avaliar a divergencia genetica entre 31 variedades de videira do Banco de Germoplasma da Embrapa Semiarido, considerando caracteristicas de qualidade, compostos de importância funcional e atividade antioxidante dos frutos. Foram avaliadas nas bagas as seguintes caracteristicas: teor de solidos soluveis (SS), acidez titulavel (AT), relacao SS/AT, resistencia da baga a forca de compressao, teor de taninos (dimeros, oligomericos e polimericos), polifenois extraiveis totais, antocianinas totais, flavonoides amarelos e atividade antioxidante. Foi utilizada a distância generalizada de Mahalanobis para quantificar a divergencia genetica entre as variedades. Como estrategias de agrupamento, foram empregados UPGMA e a analise de variaveis canonicas. A variabilidade genetica para teores de compostos fenolicos, determinados por meio de taninos polimericos, de polifenois extraiveis totais e de antocianinas totais, existentes em variedades de videira do Banco Ativo de Germoplasma da Embrapa Semiarido permitiu a identificacao de genotipos divergentes com potencial aproveitamento em futuras acoes de melhoramento voltadas para a melhoria das propriedades funcionais.