Rogério Figueiredo Daher

Divergência genética em tomate estimada por marcadores RAPD em comparação com descritores multicategóricos

The estimation of genetic variability in a germplasm bank is important not only for the conservation of the genetic resources, but also for applications in plant breeding. The genetic divergence among 78 tomato accessions was studied, based on 74 RAPD markers. Also, a correlation between the molecular profile and 27 morphological and agronomic data was performed. Cluster analysis (UPGMA), used to study the data, resulted in 13 groups that were correlated with five descriptors (growth habit, leaf type, fruit color, locule number, and fruit shape). Some groups had particularities, such as group IV that assembled accessions with pear shape fruits; group VII, that clustered accessions with bacterial wilt resistance, and group IX, that gathered accessions with potato leaf type. Bootstrap analysis revealed few consistent clusters. The results showed a positive and significant correlation between the matrixes generated out of qualitative and molecular data (t = 14.02). Mantels correlation was highly significant, but with a low value (r = 0.39), which suggests that for a wise use of the germplasm bank accessions, both characterization, molecular and morphoagronomic, should be carried out.

Correlações entre caracteres agronômicos em dois ciclos de seleção recorrente em milho-pipoca

Engenheiro Agronomo, Doutor, Professor, Departamento de Agronomia, Universidade Estadual de Maringa (UEM), Maringa, PR. Bolsista do CNPq.RESUMOCom o proposito de monitorar o comportamento deblocos genicos em diferentes geracoes de selecao recorrente emmilho pipoca, quantificaram-se as correlacoes fenotipica,genotipica e de ambiente entre caracteres agronomicos, em doisciclos de selecao recorrente. O primeiro ciclo foi formado porfamilias de irmaos completos e o segundo ciclo por familias S

Análise de trilha de caracteres forrageiros do capim-elefante (Pennisetum purpureum Schum.)

The main goals of this work was to obtain estimates of phenotype, genotype and residual correlation coefficients and display genotype correlations in direct and indirect effects (path analysis) of height, diameter of stem at the base and number of tillers per meter (explanatory independent variables) on dry matter production (basic dependent variable) of elephantgrass clones in two harvest periods at conditions of northern Rio de Janeiro State, Brazil. Great differences among estimates in two harvest periods were observed, however it could be concluded that height of plants at cutting influenced dry matter production mainly in conditions of high tillering capable clones. Number of tillers per meter and diameter of stem explained better dry matter production potential, acting, respectively, in an direct and inverse way, alternating according to environmental conditions during growth.

Genetic divergence among elephantgrass cultivars assessed by RAPD markers in composit samples

ABSTRACT: Elephantgrass Pennisetum purpureum( Schum.) is native to regions of tropical Africa and wasintroduced in Brazil around 1920 through plantings imported from Cuba. It is currently one of the mostwidespread forage plants throughout the country. At first, there were two cultivars, Napier and Mercker, withwell defined characteristics. New genotypes arose and it is believed that the large number of cultivars existingtoday in germplasm bank is due to duplicates. DNA markers for cultivar characterization are a very valuabletool, especially in situations where morphological and isoenzymatic markers have already been used as inthe case of elephantgrass. Thus RAPD markers were used to estimate the genetic divergence among theNapier group elephantgrass cultivars from the elephantgrass Active Germplasm Bank at EMBRAPA DairyCattle. The polymerase chain reaction with 37 arbitrary primers from the OPERON Technologies series supplied94 polymorphic and 73 monomorphic bands. From the matrix of complement of the Nei index, cluster analysisby the Tocher optimization method formed three clusters. Pearson correlation among genetic distance estimatesobtained from the DNA markers and the isoenzymatic markers showed the consistency of both the methodsin assessing genetic divergence among elephantgrass cultivars. No duplicates were found in the treatmentsassessed.Key words:

Estabilidade da produção forrageira em clones de capim-elefante (Pennisetum purpureum Schum.)

Quatorze clones e tres cultivares de capim-elefante foram avaliados no delineamento em blocos ao acaso, com quatro repeticoes. Objetivou-se estimar parâmetros de estabilidade pelas metodologias de Plaisted & Peterson (1959), Lin & Binns (1988) e Kang (1988), com base na producao de materia seca (MS), em kg/ha.corte, num total de 12 cortes (medidas repetidas no tempo como ambientes). O clone CNPGL 91 F11-2 e a cultivar Pioneiro apresentaram alta estabilidade e produtividade pelos metodos utilizados, destacando-se como promissores para as condicoes de Campos dos Goytacazes, RJ.

Diversidade genética em quiabeiro baseada em marcadores RAPD

RAPD markers were utilized to estimate the diversity among 42 Abelmoschus and 1 Hibiscus accessions . The genetic distances were based on the arithmetic complement of the Jaccard index. For this purpose we used the multivariate analysis technique by hierarchycal single linkage and the Tocher methods to obtain the genotypes agglomeration as well as to analyze the methods employed. Thirty-one random decamer primers were used do amplify DNA by the polymerase chain reaction (PCR) and 103 RAPD fragments were generated. The hierarchycal method of single linkage has separated 43 genotypes, in a general way, according to the botanical species, forming six different groups. The genetic distances projection on the bidimentional level confirmed that the first and largest group has united A.esculentus and A. caillei accessions.On the other hand, the Tocher method grouped 90% of the germoplasm at group I, including A. moschatus and A. manihot accessions, besides the other two previous species. The Tocher optimization method allowed the formation of just 4 genotype groups. There was only partial coherence to the hierarchycal grouping analysis. The Tocher group I accessions regrouping by the hierarchycal method revealed the existence of a most important genetic heterogenity on the studied germplasm.

Effect of mini-sprinkler irrigation system on Heterorhabditis baujardi LPP7 (Nematoda: Heterorhabditidae) infective juvenile

Entomopathogenic nematodes (EPNs) are currently being used as successful biological control agents of soil-dwelling insect pests. Previous field and greenhouse studies demonstrated that application techniques and non-biotic factors (temperature and pressure) have a significant effect on EPNs efficacy. The objective of this study was to evaluate the influence of an irrigation spray application system on the viability, infectivity and host search capability of Heterorhabditis baujardi LPP7 (Nematoda: Heterorhabditidae) infective juveniles (IJ). Two assays were proposed. Their viability was evaluated under the microscope after the IJ passed through the irrigation system. Infectivity on Galleria mellonella larvae, and host search capability, as evidenced by larval mortality, were evaluated in containers (Experiment 1). In the field (Experiment 2), mortality of G. mellonella larvae was evaluated under different nematode concentrations (0, 100,000, 300,000 and 500,000 IJ per tree). No differences were recorded on the viability, infectivity and host search capability of the IJ in Experiment 1. In Experiment 2, differences were recorded among the different concentrations used (p < 0.05), and a higher mortality was observed at the highest nematode concentration (28.3% and 37% in each one of the two experiment repetitions). This irrigation system did not affected adversely the viability, infectivity and host search capability of H. baujardi LPP7.

Introdução e Avaliação de Clones de Capim-Elefante (Pennisetum purpureum Schum.) em Campos dos Goytacazes, RJ

Fifteen intra specific hybrids and two cultivars of elephant grass were evaluated in a randomized block design with four replicates. The experiment was carried out at the Forage Production Section of LZNA/CCTA of Universidade Estadual do Norte Fluminense, Campos dos Goytacazes, RJ, from February/95 to December/97, resulting on 12 harvests. The materials were evaluated for total dry matter (DM) production, dry season production, contribution of dry season to total annual production, percentage of leaves, height (m), diameter of stem at the base (mm) and number of tillers per meter. Except for clones CNPGL 91: F28-1, F01-2, F13-2, F10-2 and the Mineiro cultivar, all of them were satisfactory for total dry matter (DM) production, while DM production during the dry season, contribution of dry season to total annual production and percentage of leaves, presented no significant differences among clones. Multivariate analysis indicated the superiority of group 2 (Pioneiro e CNPGL 91 F27-5) and 5 (CNPGL 91 F25-3 e CNPGL 91 F06-3) to total DM production, consisting on divergent and highly adapted groups in Campos dos Goytacazes, RJ. The variables: diameter of stem, plant height in cutting at wet season and plant height in cutting an dry season were the most important in order to explain the dispersion of clones in bidimensional space.

Contribution of components of production on snap bean yield

Aiming to estimate the path coefficients among morphological traits and effects of production components on the yield of grains and pods, thirty snap bean genotypes (27 lines and three commercial controls) were evaluated in Bom Jesus of Itabapoana-RJ. The experiments were carried out in a randomized block design, with four replications, from May to June, in 2009 and 2010. Eight traits were evaluated and the number of pods per plant, associated with high genetic correlation, is the character with the most significant direct effect on productivity. There is a high rate of genotypic association between the yields of pods and grains, as well as direct effects of high magnitude and positive signal between them, indicating that the selection for increased pod yield allows increased grain yield.

Critical disease components of common bacterial blight to effectively evaluate resistant genotypes of snap bean

Common bacterial blight (CBB) caused by Xanthomonas axonopodis pv. phaseoli (Xap) is the main bacterial disease of snap bean. The present work aimed to select snap bean genotypes that are resistant to CBB based on three components of resistance: area under the disease progress curve, latent period, and lesion diameter on pods (DL). A completely randomized two-factor factorial design with six replications was used to evaluate leaves and pods of 14 snap bean and three common bean genotypes (PI 207262, BAC-6 and A-794) with high resistance to CBB. Two Xap isolates, 1394-98 and 775-90, were used to inoculate leaves and pods. Data were analyzed using nonparametric statistics. Significant differences were observed among the evaluated genotypes for all of the components of resistance, except for DL. The snap bean UENF 1482 demonstrated good performance in two disease resistance components. For this reason, this genotype can be recommended for use in breeding programs that aim to generate snap bean genotypes resistant to Xanthomonas axonopodis pv. phaseoli.