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Villela R.P.,Federal University of Lavras | de Souza R.J.,Federal University of Lavras | Guimaraes R.M.,Federal University of Lavras | Nascimento W.M.,CP 218 | And 3 more authors.
Revista Brasileira de Sementes | Year: 2010

Studies on lettuce seed production in different seasons may provide a better understanding for growers to use suitable management practices which could increase their production and maximize their profits. Environmental conditions during the different stages of plant and seed development may affect lettuce physiological seed quality. The objective of this study was to evaluate the performance of eight lettuce cultivars regarding seed production and seed physiological quality under greenhouse conditions in spring/ summer and in autumn/ winter at Lavras - MG region, Brazil. Plant tasselling, anthesis and seed production were evaluated. After harvesting and processing, seeds were weighed and evaluated for germination, first count, germination rate at 20, 25, 30 and 35 °C, seedling emergence and accelerated aging (41 °C/48 and 72 hours). The highest lettuce seed yield under greenhouse conditions was observed during the autumn/ winter season and higher yield and seed quality were obtained using the 'Vera' cultivar. However, seed production of the 'Luisa' cultivar during the summer increased germination at high temperatures. The 'Lívia' and 'Simpson' cultivars grown in the spring/summer season and the 'Elisa' cultivar grown in the autumn/winter season showed lower seed vigor.

Ramiro D.,CIRAD - Agricultural Research for Development | Jalloul A.,Damascus University | Petitot A.-S.,CIRAD - Agricultural Research for Development | Grossi de Sa M.F.,Embrapa Cenargen | And 2 more authors.
Tree Genetics and Genomes | Year: 2010

In plants, WRKY proteins are a group of transcription factors existing as a gene superfamily that play important roles in regulation of defense response pathways. To assess the diversity of this protein family in coffee (Coffea spp.), data mining methods were used on a set of around 200,000 coffee expressed sequence tags. A total of 53 different putative WRKY genes were obtained, but only 22 unigenes encoding a protein with a WRKY domain were identified, eight of which are supported by full-length cDNA sequences. Alignment of WRKY domain sequences of the coffee unigenes and 72 Arabidopsis thaliana WRKY genes showed that the 22 coffee WRKY members were distributed among the main A. thaliana WRKY subgroups and shared conserved peptide domains. To assess the involvement of WRKY genes in coffee defense response pathways, their expression was analyzed under biotic (nematode and rust fungus infection), hormonal (salicylic acid, methyl-jasmonate), and wounding treatments, leaf senescence, and fruit development. Five members of WRKY groups IId and III were regulated only by pathogens and hormone treatments. Although a significant correlation of WRKY genes expression after MeJA and rust treatments was observed, expression of coffee genes involved in JA biosynthesis and lipoxygenase (EC activity assays did not support the involvement of JA in the early coffee resistance responses to the rust pathogen. The five WRKY transcription factor members identified might play important roles as regulators of pathogen resistance responses and could be useful for improving coffee tolerance to various biotic stresses. © 2010 Springer-Verlag.

Luz J.M.Q.,Federal University of Uberlandia | Silva S.M.,Federal University of Uberlandia | Habber L.L.,EMBRAPA - Empresa Brasileira de Pesquisa Agropecuaria | Marquez M.O.M.,Iac Instituto Agronomico Of Campinas
Revista Brasileira de Plantas Medicinais | Year: 2014

The objectives of this study were to evaluate the biomass, yield and composition of essential oil of Melissa officinalis L. under differents seasons, systems of planting and fertilizations. The experimental design was a randomized block design (RBD), in a factorial 2 x 2 x 2 with two seasons of harvest (summer and winter), two systems of planting (greenhouse and field) and two types of fertilizer (mineral and organic). The harvest consisted of cutting all plants of central line. After harvest, it were evaluated the leaf fresh weight, height of the plant, length and width of the leaves. The essential oil extraction was performed by hydrodistillation and the chemical composition was performed by gas chromatography coupled by mass spectrometry. The major constituents were geranial and neral in summer harvest and geranial, neral and citronellal in winter harvest. The conditions of the greenhouse and the summer presented the better biomass, higher yield of oil and higher rate of citral. © 2014, Instituto de Biociencias. All rights reserved.

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