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Fungi associated to bark lesions of Eucalyptus globulus stems in plantations from Uruguay
Alonso, Raquel;Tiscornia, Susana;Alfenas, Acelino Couto;Bettucci, Lina;
Revista árvore , 2009, DOI: 10.1590/S0100-67622009000400001
Abstract: trees with stem bark lesions are frequently observed in eucalyptus globulus labill. plantations, particularly in the central west region of uruguay. these lesions constitute a problem for trunk decortications at harvest and they also facilitate the access of fungi that could cause wood decay. seven, three and oneyear-old plantations, located at three sites in close proximity were selected. four types of trunk lesions were present in trees regardless the age of plantation and more than one type was found in each plantation. the aim of this study was to investigate the fungal composition associated with these lesions and compare them to healthy tissues and try to find out the origin of these symptoms. another purpose was to elucidate the real role of the fungi considered pathogens by means of experimental inoculations. segments from lesions and healthy tissues yielded 897 fungal isolates belonging to 32 taxa, 681 isolates from bark lesions and 216 from healthy tissues. both healthy and symptomatic tissues showed similar fungal species composition, but with differences in frequencies of colonization. cytospora eucalypticola van der westhuizen, botryosphaeria spp., pestalotiopsis guepinii (desm.) stey. and penicillium spp. were the dominant species isolated. as symptoms were not reproduced after experimental inoculation with botryosphaeria ribis grossenb. & duggar and b. eucalyptorum crous, & m.j. wingf, it could be suggested that these lesions were originated by unfavorable environmental conditions. the frost that occurred for several days out of season and flooding may have been involved in the development of bark lesion.
Eficiência de fungicidas sistêmicos no controle da ferrugem do Eucalyptus
Zauza, Edival ?ngelo Valverde;Couto, Michele Margarido Fonseca;Maffia, Luiz ?ntonio;Alfenas, Acelino Couto;
Revista árvore , 2008, DOI: 10.1590/S0100-67622008000500007
Abstract: curative and protective effects of systemic fungicides (azoxystrobin, triadmenol, tetraconazole, tebuconazole and the mixture epoxiconazole + pyraclostrobin) against eucalyptus rust were evaluated. to evaluate the curative effect, eucalyptus plants were sprayed with an inoculum suspension (2 x 104 urediniospores /ml) and with each fungicide after 0, 4, 7, or 10 days. for the protective effect, the plants were sprayed with each fungicide and with the inoculum suspension after 0, 7, 14, 21, or 28 days. the number of pustules/leaf, sori/foliar area, and urediniospores/sorus was determined on the first two apical leaves. the best curative effect was achieved with azoxystrobin, tebuconazole, epoxiconazole + pyraclostrobin, and triadimenol, since the number of sori/foliar area and urediniospores/sorus was reduced when applied up to 7 days after inoculation. regarding protective effect, azoxystrobin and triadimenol were the most effective fungicides, as no pustules formed on the leaves up to 21 days after spray. azoxystrobin, tebuconazole, triadmenol and trifloxystrobin were absorbed within 30 min after application and no p. psidii infection was detected.
Controle químico da queima de folhas e da mela de estacas de eucalipto, causadas por Rhizoctonia spp.
Silveira, Silvaldo Felipe da;Alfenas, Acelino Couto;Maffia, Luís Ant?nio;Suzuki, Márcio Shiguero;
Fitopatologia Brasileira , 2003, DOI: 10.1590/S0100-41582003000600010
Abstract: to achieve the chemical control of leaf scorch and web blight of eucalyptus (eucalyptus spp.) cuttings in forest nurseries, 12 fungicides were assayed against one isolate of rhizoctonia solani ag1-ib (rh-2). seven fungicides (methyl-tolclophos, benomyl, pencycuron, iprodione, thiabendazol and captan) completely inhibited mycelial growth under concentrations lower than 100 ppm of active ingredient on pda culture. additionally, the sensibility (ec50 = estimated dose for 50% inhibition of mycelial growth) to methyl-tolclophos, benomyl, pencycuron and iprodione of another eight isolates differing in virulence, morphology, anastomosis groups, and proteins and isozyme profiles was evaluated. little differences in sensitivity was observed in some combinations of fungicides-isolates. however, the eight isolates were sensitive to the four tested fungicides (ec50 < 11 ppm). under artificial conditions of inoculations, sprays of iprodione (1,5 g/l), benomyl (1 g/l), methyl-tolclophos (1,5 g/l), thiram (2,1 g/l), captan (2 g/l), and pencycuron (2 g/l) significantly (a=5%) reduced the incidence of leaf scorch on shoots of plants in vessels. pruning of diseased shoots in clonal gardens (field) associated with weekly sprays of iprodione (1 g/l) or mixtures of benomyl (0,5 g/l) + captan (1 g/l) alternating with benomyl (0,5 g/l) + thiram (1 g/l), reduced the incidence of web blight on cuttings under shade house conditions (a=5%).
The use of self-incompatibility in the production of hybrid eucalyptus seed by `Aracruz Celulose' in Brazil
Junghans, Tatiana Góes;Peters-Robinson, Ingrid;Bertolucci, Fernando L.;Alfenas, Acelino Couto;
Genetics and Molecular Biology , 1998, DOI: 10.1590/S1415-47571998000300015
Abstract: self-incompatibility found in a eucalyptus grandis clone was used to promote interspecific hybridization between e. grandis and e. urophylla clones. the interspecific hybridization achieved in an open-pollinated commercial seed orchard planted in espírito santo, brazil was evaluated by the multi-locus outcrossing rate (tm) of the seed producing clone, e. grandis. the percentage of outcrossed seeds reached 95.9%. the outcrossing rate of individual trees was quite variable, but was always above 70.0%. wright's coefficient was negative (f = -0.30) revealing an excess of heterozygous genotypes in the progeny. genetic parameters confirmed the high degree of hybridization expected in this orchard. the 800-m wide protection belt of native tropical forest that surrounds this orchard has significantly reduced pollen contamination, in comparison to a 400-m wide belt used in another local seed orchard.
Linkage analysis between dominant and co-dominant makers in full-sib families of out-breeding species
Alves, Alexandre Alonso;Bhering, Leonardo Lopes;Cruz, Cosme Dami?o;Alfenas, Acelino Couto;
Genetics and Molecular Biology , 2010, DOI: 10.1590/S1415-47572010000300021
Abstract: as high-throughput genomic tools, such as the dna microarray platform, have lead to the development of novel genotyping procedures, such as diversity arrays technology (dart) and single nucleotide polymorphisms (snps), it is likely that, in the future, high density linkage maps will be constructed from both dominant and co-dominant markers. recently, a strictly genetic approach was described for estimating recombination frequency (r) between co-dominant markers in full-sib families. the complete set of maximum likelihood estimators for r in full-sib families was almost obtained, but unfortunately, one particular configuration involving dominant markers, segregating in a 3:1 ratio and co-dominant markers, was not considered. here we add nine further estimators to the previously published set, thereby making it possible to cover all combinations of molecular markers with two to four alleles (without epistasis) in a full-sib family. this includes segregation in one or both parents, dominance and all linkage phase configurations.
Isozymic variability in a Brazilian collection of annatto (Bixa orellana L.)
Carvalho, Jane Fiuza Rodrigues Portela de;Robinson, Ingrid Peters;Alfenas, Acelino Couto;
Pesquisa Agropecuária Brasileira , 2005, DOI: 10.1590/S0100-204X2005000700005
Abstract: the objectives of this work were to optimize the isozyme electrophoresis technique for bixa orellana, and use isozyme markers for a preliminary survey on the genetic variability in brazilian annatto germplasm accessions. collection consisted of seed samples from sixty open pollinated trees, representing two northern and four southern geographic provenances. the extraction, electrophoresis, and interpretation of annatto isozymes are described. three out of the twenty-one identified isozyme loci were polymorphic in the collection. the percentage of polymorphic loci (p = 21.05) and the expected heterozygosity in annatto (ht = 0.064) were low, compared to other tropical woody species. a upgma phenogram, constructed with nei's genetic distances, clearly separated the germplasm provenant from north and central brazil. variability was significantly higher among the accessions from maranh?o. a sharp genetic differentiation was detected between accessions from maranh?o and pará states, despite their geographical proximity. the distinctive isozyme polymorphism, observed in the accessions from maranh?o, together with reports on local morphological heterogeneity in annatto fruit shape, color, and pubescence, calls for more detailed genetic and taxonomic investigation.
Crescimento de mudas e produtividade de minijardins clonais de eucalipto tratados com rizobactérias selecionadas
Mafia, Reginaldo Gon?alves;Alfenas, Acelino Couto;Ferreira, Eraclides Maria;Zarpelon, Talyta Galafazzi;Siqueira, Leandro de;
Revista árvore , 2005, DOI: 10.1590/S0100-67622005000600002
Abstract: the effect of plant growth promoting rhizobacteria was evaluated for root biomass of cuttings, number of mini-cuttings per mini-stump and productivity of mini-clonal hedges (number of mini-cuttings x rooting percent) of eucalyptus in the nursery. except for clone 57, all other showed increase in root biomass, with an average of 53, 52 and 69% for clones 129, 1274, and 7074 respectively. in general, significant differences were found for mini-cutting production, but not for the productivity index (number of mini-cuttings x rooting percent). isolate s1 had a substantial effect on the production of mini-cuttings, with increases varying from 11 to 23% for clones 129 and 1274 respectively. for clone 7074, the average increase was 15%. the results clearly indicated that rhizobacteria could be employed to maximize the vegetative propagation of eucalyptus by cutting.
Tombamento de mudas de espécies florestais causado por Sclerotium rolfsii Sacc
Mafia, Reginaldo Gon?alves;Alfenas, Acelino Couto;Resende Júnior, Márcio Fernando Ribeiro de;
Revista árvore , 2007, DOI: 10.1590/S0100-67622007000400007
Abstract: the host range of sclerotium rolfsii was evaluated by controlled inoculation of the following native and exotic forest species: anadenanthera peregrina (angico vermelho), chorisia speciosa (paineira rosa), clitoria fairchildiana (sombreiro), copaifera langsdorffii (copaíba), delonix regia (flamboyant vermelho), enterolobium contortisiliquum (orelha de negro), leucaena leucocephala (leucena), mabea fistulifera (canudo-de-pito), platymiscium pubescens (tamboril da mata), senna macranthera (fedegoso), spathodea campanulata (espatódea) e tabebuia avellanedae (ipê roxo). the fungus caused damping-off in pre and post emergence in all tested species.
Resitência de Eucalyptus globulus e Eucalyptus nitens à ferrugem (Puccinia psidii)
Xavier, Adelica Aparecida;Von. Sanfuentes, Eugênio;Junghans, Davi Theodoro;Alfenas, Acelino Couto;
Revista árvore , 2007, DOI: 10.1590/S0100-67622007000400018
Abstract: eucalyptus globulus and eucalyptus nitens were evaluated for resistance to rust caused by puccinia psidii. seedlings were inoculated with a single urediniosporic pustule isolate of p. psidii (ufv-2) obtained from e. grandis from itapetininga, sp. disease assessment was carried out 12 days after inoculation based on a rust rating scale with four class of severity (s0, s1, s2 and s3). percentages of resistant plants were 60% and 50% for e. globulus and e. nitens, respectively. the high intra-specific variability found in this study allows using the clonal propagation of resistant genotypes in commercial plantations or in breeding programs.
Método de sele??o e identifica??o de fontes de resistência à murcha do eucalipto causada por Ceratocystis fimbriata
Mafia, Reginaldo Gon?alves;Alfenas, Acelino Couto;Ferreira, Eraclides Maria;Binoti, Daniel Henrique Breda;
Revista árvore , 2011, DOI: 10.1590/S0100-67622011000500007
Abstract: the objective of this work was to develop a screening method and to identify resistance source to eucalyptus wilt caused by ceratocystis fimbriata. the inoculation of 5 ml of pathogen inoculum (2.5 × 104 spores/ml) on the wound root crown of seedlings at 60 days of age was the most efficient method to reproduce the disease symptoms. for this method, disease severity and plant mortality in function of time after inoculation were assessed. a 30-day period after inoculation was sufficient to reproduce disease symptoms. the developed inoculation protocol showed high performance (400 plants/h), and less space consume, when compared with other methods, mainly because it enables the inoculation of young eucalyptus seedlings (60-90 days of age). in the second phase of this work, it was evaluated the eucalyptus inter-specific resistance to c. fimbriata by using the species: eucalyptus camaldulensis, e. dunnii, e. grandis, e. pellita, e. saligna, e. tereticornis and e. urophylla. there was resistance segregation for all species and according to the origin place of the population. for e. urophylla, for example, occurred the greatest variations among the number of resistant individuals and susceptible to diseases. those variations can be linked to seed precedence and to genetic improvement program characteristics.
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