Walter José Siqueira

Instituto Agronômico de Campinas, Conceição de Campinas, São Paulo, Brazil

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Publications (61)182.34 Total impact

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    ABSTRACT: The study aimed to assess the reaction to Tomato yellow vein streak virus (ToYVSV) of determinate-growth tomato breeding lines of the Instituto Agronomico de Campinas (Campinas Agronomic Institute) germplasm collection and to select resistant plants. The experiment was carried out from August 2008 to February 2009 in greenhouse conditions. The geminivirus isolate used was collected in a tomato commercial field, in Sumaré, São Paulo State, Brazil. The experimental design was completely ramdomized blocks, with 25 treatments, four replications, and 30-plant plots. Virus transmission was carried out in cages containing viruliferous whiteflies (Bemisia tabaci B biotype). Plant reaction to the pathogen was evaluated by means of the percentage of symptomless plants 40, 50, 57 and 64 days after transplanting. Virus detection in each genotype was carried out using PCR. Although all genotypes showed plants with and without ToYVSV symptoms, lines IAC-TG 17 and LA 462 (Solanum peruvianum) stood out due to the highest percentage of symptomless plants in the four evaluation dates. Therefore, considering the genotypes evaluated and the edaphoclimatic conditions in which this work was carried out, lines IAC-TG 17 and LA 462 can be used as sources of resistance to ToYVSV.
    Full-text · Article · Jul 2015 · Horticultura Brasileira
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    Full-text · Dataset · Feb 2015
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    ABSTRACT: The major inconsisten regeneratio this study, regeneratio program we and G3 gen explants w micrograftin genetic sta cytometry reported fo tetraploid a other geno preserves t TA Citros Sylv limitation i nt and unsta on system is , the intera on shoots fro ere evaluate notypes, res were collecte ng technique bility of micr and DNA p or the first t and 5% of p otypes. Thus the clonal fid
    Full-text · Article · Sep 2014 · AFRICAN JOURNAL OF BIOTECHNOLOGY
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    ABSTRACT: Aluminum (Al) is a limiting factor of crop yields on acidic soils. Ion aluminum (Al3+) acts primarily in plant root system retarding its growth and development, leading to the reduction of lateral roots number, and consequently the decrease of vegetal production. Most of coffee producing areas are located in acidic soils, which have Al3+ contents enough to damage plant development. Despite the advances in the understanding of physiological and genetic mechanisms of Al tolerance/susceptibility, few are known about Al ion action in coffee plants. This report describes the expression analysis of genes related to aluminum stress in germinating seeds of two cultivars of C. arabica (Catuaí Amarelo IAC 62 and Icatu Vermelho IAC 4045) when challenged with Al3+. In silico analyses of Brazilian Coffee Genome Project (BCGP) database were used to select genes previously found to be related with Al-stress. The expression profile of these genes in Catuaí and Icatu was evaluated through Quantitative PCR (qPCR). Based on our data, we suggest that both analyzed cultivars displays mechanisms of resistance or exclusion, which occurs outside the cell excluding Al3+ assimilation, and mechanisms of tolerance that occurs inside the cell after Al3+ absorption. The major difference is the timing of activation of each mechanism. While Catuaí tends to use resistance mechanisms in early stages of stress, Icatu uses tolerance strategies. In late stages, both cultivars seem to display tolerance mechanisms, but Icatu also displays Al-exclusion strategy.
    Full-text · Article · Dec 2013 · Tropical Plant Biology
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    ABSTRACT: The percentage and speed of germination and the vigor of Acrocomia aculeata seedlings during early development can be important for obtaining seedlings for the commercial cultivation of this palm. Thus, the variation in germination and vegetative traits was studied in 63 A. aculeata half-sib progenies considered promising for biodiesel production, which originated from natural populations in the states of Sao Paulo and Minas Gerais. The seeds were weighed on an analytical balance and subsequently received pre-germination treatments. A randomized block design was employed at sowing, with two replicates and plots of 128 seeds. The traits evaluated were germination percentage and germination speed index. After germination and seedling transplantation to plastic bags in agricultural greenhouse conditions, the following biometric traits were measured: plant height, number of leaves, stem diameter and number of spines. Analysis of variance was performed, means were tested, and the heritability and correlation between traits were calculated for all evaluated traits. The mean germination percentage obtained was 59.07%, ranging from 19.14% to 98.64%. The mean germination speed index was 1.51, ranging from 0.34 to 3.39. Positive genetic correlations were observed for all traits, as well as high heritability. The evaluated A. aculeata progenies showed great genetic variability, demonstrating that successful selection of superior progenies is possible.
    No preview · Article · Nov 2013 · Industrial Crops and Products
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    ABSTRACT: Resumen El aceite de Jatropha curcas como biocombustible es conocido especialmente por su excelente calidad. Sin embargo , problemas relacionados con la baja e inconstante productividad de la planta hacen que el uso comercial de éste aún no sea viable. La solución para esto es desarrollar cultivares estables y productivos. Sin embargo, el cruzamiento genético de J. curcas se ve afectado por la estrecha base genética. Una mayor variabilidad genética puede lograrse mediante cruzamientos interespecíficos entre J. curcas y especies congéneres. Aunque estos cruzamientos a menudo presentan incompatibilidad genética, ésta puede solucionarse con el uso de biotecno-logía. Por tanto, el objetivo del estudio fue verificar, mediante microscopía de fluorescencia, el tipo de incom-patibilidad (pre o poscigótica) que se presenta en el cruzamiento entre J. curcas y J. multifida, J. integerrima y J. podagrica. Los resultados indicaron que la barrera genética fue poscigótica en todos los cruzamientos. Así, se realizaron experimentos para establecer el rescate embrionario in vitro, con el fin de obtener híbridos inte-respecíficos. Cuando se colocaron en el medio de cultivo apropiado algunos embriones germinaron, pero este proceso no fue uniforme. Hubo embriogénesis directa e indirecta, aun cuando se trató del mismo cruzamiento y medio de cultivo. Los embriones fueron transferidos a medio de cultivo para su multiplicación y después se convirtieron en plántulas híbridas. Después de la aclimatización fue posible obtener plantas híbridas de todos los cruzamientos mencionados, de manera exitosa. Estos híbridos, que aportan mayor variabilidad genética, contribuirán al éxito reproductivo de J. curcas. Palabras clave: rescate embrionario, híbrido interespecífico, incompatibilidad genética, microscopía de fluores-cencia, Jatropha. Rescate embrionario in vitro en el cruzamiento de Jatropha curcas con J. integerrima, J. multifida y J. podagrica
    Full-text · Conference Paper · Oct 2013
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    ABSTRACT: The growing demand for renewable energy sources will increase the demand for oilseeds in Brazil and worldwide. This demand will only be supplied if plant varieties with exceptional agronomic and chemical traits are developed. This process can be accelerated by application of biotechnology and molecular biology techniques, as we have done in the case of Jatropha curcas, a perennial oilseed. We have used two strategies: (1) Exploitation of pre-existing variability in the germplasm of J. curcas evaluated through morphological, molecular and chemical markers (such as fatty acid and phorbol esters content). We also investigated self-fertilization with selected genotypes to analyze the effects of inbreeding, particularly with regard to the production of non-toxic, smaller, male-sterile and gynoic plants; and (2) Increase the genetic variability through interspecific hybridization and biotechnology. Despite the post-zygotic incompatibility encountered in most interspecific crosses, the use of artificial hybridization coupled with tissue culture techniques, such as in vitro embryo rescue and subsequent multiplication via somatic embryogenesis has yielded unprecedented results in the form of rare hybrids between J. curcas and other species of this genus. So far, we have obtained more than 80 F1 hybrids and 140 BC1 × F1 backcross progenies. Evaluation of these hybrids and the continuation of this line of research will greatly expand the germplasm bank of Instituto Agronômico de Capinas (IAC) and should contribute significantly to rapid production and release of new improved cultivars. In addition to their application in assessing genetic variability, molecular markers were useful to confirm F1 hybrids and BC1 generations by excluding the possibility of apomixis and to select suitable plants for genetic breeding.
    Full-text · Chapter · Jan 2013
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    ABSTRACT: Premise of the study: A set of eight microsatellite (simple sequence repeat [SSR]) markers for Lippia alba, an important medicinal and cosmetic plant, was developed to aid studies of genetic diversity and to define efficient strategies for breeding programs. Methods and results: Using a (CT)(8)- and (GT)(8)-enriched library, a total of 11 SSR loci were developed and optimized in L. alba. Of the 11 loci, eight were found to be polymorphic after screening 61 accessions from two populations. The parameters used to characterize loci were expected heterozygosity (H(e)) and number of alleles. A total of 44 alleles were identified, with an average of 5.5 alleles per loci, which were moderately to highly informative according to H(e). Conclusions: These new SSR markers have potential for informing genetic diversity, allele mining, and mapping studies and will be used to generate information for breeding programs of L. alba.
    Preview · Article · Jul 2012 · American Journal of Botany
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    ABSTRACT: The metabolomic profiling based on the application of multivariate analysis (principal component analysis, PCA) of positive mode electrospray ionization mass spectrometric (ESIMS)and 1H nuclear magnetic resonance (NMR) data of crude extracts highlighted some species characterized by lignans (P. solmsianum, P. truncatumand P. cernuum), neolignans (P. regnellii)and chromenes (P. gaudichaudianum). A specific analysis focusing on species having pendantand globular inflorescences (P. caldense, P. carniconnectivum, P. bowieiand P.permucronatum) or amides-producing species indicated higher potential of the methodology in determining similaritiesand establishing priorities for further phytochemical investigation. Such intraspecific analysis applied to analyzed seedling leaves of the P. solmsianum, P. regnelliiand P. gaudichaudianum species revealed the production of dillapioleand apiole instead of lignans, neolignans or prenylated benzoic acid, produced by the adult leaves, respectively. In case of amides-producing species, a similar profile was observed regardless the developmental stage.
    Full-text · Article · Dec 2011 · Journal of the Brazilian Chemical Society
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    ABSTRACT: The aromatic and medicinal species Lippia alba is vigorous and rugged native to the South America (Atlantic Rainforest). Because it is an allogamous and self-incompatible species, natural populations have high morphological and chemical variability. This work had as objective to conduct a preliminary screening to identify new promising clones from a novel (recombinant) base population of Lippia alba with regard to its agronomic and phytochemical traits, using the linalool oil or chemotype as model. The two superior linalool clones, obtained by collection, were used as controls. Traits evaluated included: dry mass of leaves (DML), oil yield percentage (EOY%), oil production per plant (OP), and linalool percentage (LN%). Forty linalool chemotype clones were evaluated in three experiments, in a random block design with four replicates and four cuttings (clones) per plot. Besides means comparisons, multivariate analysis was used in order to aid in the preliminary selection of clones. There were positive correlations from moderate to strong for DML vs. EOY%, OP vs. EOY% and DML vs. OP. Linalool clones superior or similar to both controls were identified for the DML, EOY%, OP, and LN% traits (univariate analyses), aimed at further validating experimentation. Five distinct groups were defined in the cluster analysis (UPGMA), each containing subgroups as well.
    Full-text · Article · Dec 2011 · Bragantia
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    ABSTRACT: The study aims to obtain and select F1 resistant hybrids of tomato for fresh market and evaluate their agronomic attributes in field conditions. The work was carried out at Nunhems Experimental Station, located in Paulínia, São Paulo State, Brazil, from February to June 2008. The experimental design was completely randomized blocks with 36 treatments, four replications and ten plants per plot. Based on the grouping of means by Scott-Knott test, the performance of hybrids for seven agronomic traits showed great variability among genotypes for fruit length and width with four groups of means. There was good variability for yield per plant, and plant height with three groups of means for each character. The traits fruit number per plant, cluster number per plant, and distance between the first cluster and the ground showed little divergence with two grouping means. HE-38 and HE-14 outperformed the standard Aplauso for fruit yield per plant showing positive heterotic effects.
    Preview · Article · Sep 2011 · Horticultura Brasileira
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    ABSTRACT: Lippia alba (Mill.) N.E.Br. is an aromatic and medicinal shrub native to the American continent. Despite its potential as a source of essential oil for the pharmaceutical and cosmetics industries, few selection and genetic improvement studies have been carried out. The aim of this study was to provide genetic information on this species for breeding programs, showing its selection potential, by investigating clonal half-sib progenies. The following characteristics were evaluated per plant: leaf dry mass (LDM), total dry mass (TDM), leaf yield (LY), essential oil yield (EOY) and oil production (OP). Estimates were made for the several genetic parameters including absolute genetic gain at 30% selection intensity, correlations and relative contribution of additive and environmental effects to phenotypic correlation. Two experimental trials on 30 progenies were conducted: one in Campinas, state of São Paulo (SP), Brazil, with two harvests of the aerial part, and one in Monte Alegre do Sul, SP, Brazil, with only one harvest. The trials were conducted in a randomized block design consisting of subplots with three replications, each plot (progeny) consisting of 8 to 15 clonally-replicated plants with subplot harvesting. Variations were detected between progenies and harvests, as well as progeny/harvest interactions in the split plot experiment. High heritability and genetic gains were obtained at both sites for LDM, TDM and OP. The lowest variations among progenies were obtained for LY and EOY, highlighting selection problems. Negative additive genetic correlations were obtained for EOY × LDM, EOY × TDM, LY × TDM and LY × LDM. Selection for LDM resulted in increased oil production per plant (OP), even where there was a negative correlation between LDM × EOY.
    Full-text · Article · Aug 2011 · Scientia Agricola
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    ABSTRACT: The species Lippia alba, belonging to the Verbenaceae family, is a vigorous wild bush with aromatic and medicinal properties. Due to the presence of several essential oils, it is used among others, mostly in drugs and cosmetics, perfumes. The species is poorly studied and no genetic parameter is known to help breeding programs. The main purpose of this research was to evaluate survival (S%), branches length (BL) and fresh weight (FW), in three progenies. High heritabilities, (FM 90.2% - 94.5%; BL 95.2% - 97.1%), in the narrow sense, were observed in all progeny groups, except for S% (50.0% - 56.0%). Genetic gains were similar for all three traits, strongly suggesting the presence of large genetic variability. Additive genetic correlations were high (87.9% - 98.8%) and predominate in the phenotypic correlations (G% - 94.1% - 98.8%). Despite the high environmental correlations, their effects on the phenotypic correlations were quite small (E% 1.2 % - 5.9%).
    Full-text · Article · Dec 2010 · Bragantia
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    ABSTRACT: The species Lippia alba, belonging to the Verbenaceae family, is a vigorous wild bush with aromatic and medicinal properties. Due to the presence of several essential oils, it is used among others, mostly in drugs and cosmetics, perfumes. The species is poorly studied and no genetic parameter is known to help breeding programs. The main purpose of this research was to evaluate survival (S%), branches length (BL) and fresh weight (FW), in three progenies. High heritabilities, (FM 90.2% - 94.5%; BL 95.2% - 97.1%), in the narrow sense, were observed in all progeny groups, except for S% (50.0% - 56.0%). Genetic gains were similar for all three traits, strongly suggesting the presence of large genetic variability. Additive genetic correlations were high (87.9% - 98.8%) and predominate in the phenotypic correlations (G% - 94.1% - 98.8%). Despite the high environmental correlations, their effects on the phenotypic correlations were quite small (E% 1.2 % - 5.9%).
    Full-text · Article · Dec 2010 · Bragantia
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    Full-text · Article · Jan 2010
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    ABSTRACT: Lippia alba (Verbenaceae) is a shrub whose essential oil has important biological, pharmacological, and aromatizing properties. To reach the sustained cultivation of new species with economic potential, the present study aimed to evaluate L. alba performance for fresh leaf matter (FM), leaf dry matter (DM), virus symptoms (VS - Cucumber mosaic virus, CMV), oil yield (OY), and oil chemical composition (OC), and to evaluate DM stability and adaptability. Ten genotypes of four chemical groups (chemotypes) were evaluated in six experiments designed as randomized blocks with two plants per plot, over the whole State of São Paulo, Brazil. A 2.0 x 0.4 x 1.6 m spacing was used in Monte Alegre do Sul and Pindorama, while a 1.0 x 0.4 x 0.6 m spacing was used in Campinas, where four experiments were established under different irrigation and fertilization conditions. The genotype effect was significant (p < 0.05) for all traits evaluated, with high leaf productivity of IAC-16 (citral chemotype), best OY means in the linalool and limonene/carvone chemotypes, and susceptibility of the latter chemotype to CMV. The genotype performance oscillations in the six environments were significant for FM and DM, and despite their significance for phytochemical traits (OY and OC), they were of low magnitude. No qualitative variation was detected for OC. The IAC-2 (linalool) and IAC-13 (limonene/carvone) genotypes showed high stability and wide adaptability, and are recommended to establish initial cultivations of this species. This research also indicated genetic sources to start Lippia alba genetic breeding programs.
    Full-text · Article · Sep 2008 · Scientia Agricola
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    Preview · Article · Feb 2008
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    ABSTRACT: Caffeine inheritance was investigated in F2 and BC1F1 generations between Coffea arabica var. Bourbon Vermelho (BV) and Coffea canephora var. Robusta 4x (R4x). The caffeine content of seeds and leaves was determined during 2004 and 2005. Microsatellite loci-markers were used to deduce the meiotic pattern of chromosome pairing of tetraploid interspecific hybrids. Genetic analysis indicated that caffeine content in seeds was quantitatively inherited and controlled by genes with additive effects. The estimates of broad-sense heritability of caffeine content in seeds were high for both generations. In coffee leaves, the caffeine content (BSH) from the same populations showed transgressive segregants with enhanced levels and high BSH. Segregation of loci-markers in BC1F1 populations showed that the ratios of the gametes genotype did not differ significantly from those expected assuming random associations and tetrasomic inheritance. The results confirm the existence of distinct mechanisms controlling the caffeine content in seeds and leaves, the gene exchange between the C. arabica BV and C. canephora R4x genomes and favorable conditions for improving caffeine content in this coffee population.
    Full-text · Article · Jan 2008 · Genetics and Molecular Biology
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    ABSTRACT: O café é um dos principais produtos agrícolas, sendo considerado o segundo item em importância do comércio internacional de "commodities". O gênero Coffea pertence à família Rubiaceae que também inclui outras plantas importantes. Este gênero contém aproximadamente 100 espécies, mas a produção comercial é baseada somente em duas espécies, Coffea arabica e Coffea canephora, que representam aproximadamente 70 % e 30 % do mercado total de café, respectivamente. O Projeto Genoma Café Brasileiro foi desenvolvido com o objetivo de disponibilizar os modernos recursos da genômica à comunidade científica e aos diferentes segmentos da cadeia produtiva do café. Para isso, foram seqüenciados 214.964 clones escolhidos aleatoriamente de 37 bibliotecas de cDNA de C. arabica, C. canephora e C. racemosa representando estádios específicos do desenvolvimento de células e de tecidos do cafeeiro, resultando em 130.792, 12.381 e 10.566 seqüências de cada espécie, respectivamente, após processo de trimagem. Os ESTs foram agrupados em 17.982 contigs e em 32.155 singletons. A comparação destas seqüências pelo programa BLAST revelou que 22 % não tiveram nenhuma similaridade significativa às seqüências no banco de dados do National Center for Biotechnology Information (de função conhecida ou desconhecida). A base de dados de ESTs do cafeeiro resultou na identificação de cerca de 33.000 unigenes diferentes. Os resultados de anotação das seqüências foram armazenados em base de dados "online" em http://www.lge.ibi.unicamp.br/cafe. Os recursos desenvolvidos por este projeto disponibilizam ferramentas genéticas e genômicas que podem ser decisivas para a sustentabilidade, a competitividade e a futura viabilidade da agroindústria cafeeira nos mercados interno e externo.
    Full-text · Article · Mar 2006 · Revista Brasileira de Fisiologia Vegetal
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    Full-text · Article · Jan 2006 · Brazilian Journal of Plant Physiology

Publication Stats

2k Citations
182.34 Total Impact Points

Institutions

  • 1984-2013
    • Instituto Agronômico de Campinas
      • Centro de Café "Alcides Carvalho"
      Conceição de Campinas, São Paulo, Brazil
  • 2011
    • Instituto de Astrofísica de Canarias
      San Cristóbal de La Laguna, Canary Islands, Spain
  • 2000-2011
    • IAC
      New York, New York, United States
  • 2004
    • Universidade Federal da Bahia
      Bahia, Bahia, Brazil