Transferability and use of microsatellite markers for the genetic analysis of the germplasm of some Arachis section species of the genus Arachis

The Arachis section is the most important of the nine sections of the genus Arachis because it includes the cultivated peanut, Arachis hypogaea. The genetic improvement of A. hypogaea using wild relatives is at an early stage of development in spite of their potential as sources of genes, including those for disease and pests resistance, that are not found in the A. hypogaea primary gene pool. Section Arachis species germplasm has been collected and maintained in gene banks and its use and effective conservation depends on our knowledge of the genetic variability contained in this material. Microsatellites are routinely used for the analysis of genetic variability because they are highly polymorphic and codominant. The objective of this study was to evaluate the transferability of microsatellite primers and the assay of genetic variability between and within the germplasm of some species of the Arachis section. Fourteen microsatellite loci developed for three different species of Arachis were analyzed and 11 (78%) were found to be polymorphic. All loci had transferability to all the species analyzed. The polymorphic loci were very informative, with expected heterozygosity per locus ranging from 0.70 to 0.94. In general, the germplasm analyzed showed wide genetic variation. © 2006 Sociedade Brasileira de Genética.

Morfologia de plântulas e estádios juvenis de espécies invasoras

The morphology of 20 species of weeds that occur in the most common crops in Maringá, Paraná State, Brazil and adjacent regions were described at early developmental stages, in order to identify the species in the field and provide information for taxonomic and ecological works. Sixteen species featured epigeal-foliaceous seedlings. The seedling in Cardiospenuum halicacabum is epigeal-fleshy; in Cenchrus echinatus and Digitaria horizontalis it is hypogeal and in Commelina virginica is epigeal-cryptocotyledonar. The differentiation of the first eophyll occurred within ten (Digitaria horizontalis) to 35 days (Bidens pilosa) and the first metaphyll appeared within 22 (Commelina virginica) to 49 days (Acanthospenuum australe). The number of eophylls varied from one to four, and the phyllotaxis varied from alternate to opposite.

Crescimento de Mentha piperita L, cultivada em solução nutritiva com diferentes doses de potássio

The research aimed at the evaluation of the influence of different potassium doses on the growth and development of Mentha piperita L. The experiment was conducted with stalks rooted in a commercial substrate and transplanted to a complete nutritive solution varying the treatments as following: (a) 234 mg L-1 of K; (b) 117 mg L-1 of K; and (c) 58.5 mg L-1 of K. Plants were evaluated at 21, 42, 63, 84 and 105 days after transplanting (DAT). In this study there were determined the physiological indexes leaf area ratio (LAR), specific leaf area (SLA), net assimilatory rate (NAR) and relative growth rate (RGR) were determined. The results indicated that the decreasing of K concentration to 25% did not affect the LAR, SLA, NAR and RGR physiological indexes.

Análise de crescimento em clones de eucalipto submetidos a estresse hídrico

The aim of this study was to evaluate Eucaliptus grandis genotypes (Clones 105 and 433) in relation to drought tolerance, through growth plant analysis. Black PVC pots with 10 liter volume were used for cultivate plants in polyethilene greenhouse oriented east/west. Completely randonmized design with four treatments was used: two clones and two minimum soil water potentials (- 0.03 and -1,5 MPa) and sixteen replicates. Pots were weighed daily in order to evaluate water content and characteristic soli water curve was determined. Plant development was obtained each 15 days from planting until 60 days through total dry matter (DM), leaf area index (LAI), leaf area ratio (LAR), net assimilative ratio (NAR), specific leaf area (SLA), relative growth ratio (RGR) and absolute growth ratio (AGR). Results showed that clone 105 presented less sensibility to water deficit, which qualify it as genetic material for use under dry soil conditons. On the other hand, both clones had similar behavior with no water restrictions.

Morfofisiologia da cunhã cultivada sob estresse salino

The experiment was developed based on the importance of the nutritional factor cunhã for large and small, animals and on the growth of this forage in typical soils of the semiarid region, generally with salinity from natural or anthropogenic action. The experiment was performed in vessels with a capacity of 5kg prepared in a protected environment with full sunshine in the Department of Technology and Social Sciences (DTCS) of UNEB Campus III in Juazeiro - BA. It evaluated the effect of seven different salt concentrations on increasing levels of irrigation water electrical conductivity - ECw (0, 2, 4, 6, 8, 10 and 12 dS/m), at room temperature. The analysis of culture were taken every seven days observing the number of leaves, stem diameter, plant, plant length and total chlorophyll content at 13; 20; 27; 34 and 40 days after the start of irrigation with saline. The contents of proline, the ratio aero part/Root (AP/Rt), the root length and water content were evaluated in the 40 th day after the onset of treatment. The results showed that the elevation of ECw affected all variables.

Plantas de cobertura e adubação nitrogenada na cultura do algodoeiro

The fiber quality, productivity and favorable climate are considered key points for the development of the cotton crop in the Brazilian Cerrado. This study aimed to evaluate the effect of cover crops and N application in presowing on the cotton crop growth and yield. The experimental design was randomized blocks, consisting of a - three cover crops (radish, white oat and black oat) implanted during the winter period, b - four nitrogen levels (0, 30, 60 and 90 kg ha-1 of N) applied to the millet residues and before cotton sowing. In April 2008, evaluations were realized of plant development and also harvesting was performed of experimental plots of cotton plants. The results showed that the radish provides increased length of branches and cotton bolls of cotton crop, without yield increase, and the use of increasing doses of N up to 90 kg ha-1 decreased the amount of carimã per plant, increasing the number of reproductive branches and cotton yield.

Análise de crescimento e produtividade de cultivares de arroz de terras altas dos tipos tradicional, intermediário e moderno

The growth analysis allows the characterization and understanding of the upland rice cultivars development. This study aimed at characterizing, by using the growth analysis, the physiological components and agronomic performance, as well as the differences among traditional, intermediate and modern upland rice cultivars. The experiment was conducted under upland rice conditions, favored by the use of supplementary irrigation. The experimental design was randomized blocks, with three treatments consisting of traditional (Caiapó), modern (Maravilha) and intermediate (BRS Primavera) cultivars and eight replications. The leaf area index (LAI), instantaneous growth rate (IGR), relative growth rate (RGR), net assimilation rate (NAR) and specific leaf area (SLA), as well as grain yield and yield components, were evaluated. The intermediate and traditional cultivars presented the highest total dry matter accumulation rate, while the traditional and modern ones showed the highest LAI. The intermediate cultivar presented the highest IGR, RGR, NAR and SLA levels, as well as the highest grain yield, as a consequence of the higher spikelet fertility and 1,000 grain mass.

Global analysis of the sugarcane microtranscriptome reveals a unique composition of small RNAs associated with axillary bud outgrowth

Axillary bud outgrowth determines shoot architecture and is under the control of endogenous hormones and a fine-tuned gene-expression network, which probably includes small RNAs (sRNAs). Although it is well known that sRNAs act broadly in plant development, our understanding about their roles in vegetative bud outgrowth remains limited. Moreover, the expression profiles of microRNAs (miRNAs) and their targets within axillary buds are largely unknown. Here, we employed sRNA next-generation sequencing as well as computational and gene-expression analysis to identify and quantify sRNAs and their targets in vegetative axillary buds of the biofuel crop sugarcane (Saccharum spp.). Computational analysis allowed the identification of 26 conserved miRNA families and two putative novel miRNAs, as well as a number of trans-acting small interfering RNAs. sRNAs associated with transposable elements and protein-encoding genes were similarly represented in both inactive and developing bud libraries. Conversely, sequencing and quantitative reverse transcription-PCR results revealed that specific miRNAs were differentially expressed in developing buds, and some correlated negatively with the expression of their targets at specific stages of axillary bud development. For instance, the expression patterns of miR159 and its target GAMYB suggested that they may play roles in regulating abscisic acid-signalling pathways during sugarcane bud outgrowth. Our work reveals, for the first time, differences in the composition and expression profiles of diverse sRNAs and targets between inactive and developing vegetative buds that, together with the endogenous balance of specific hormones, may be important in regulating axillary bud outgrowth. © 2013 © The Author(2) [2013].

Evaluation of ornamental grasses submitted to water stress

The work was carried out at the College of Agricultural and Veterinary Sciences of the State University of São Paulo (UNESP/FCAV), Campus of Jaboticabal, Brazil, aiming to study the tolerance response to water stress and capacity of regeneration after mowing three different ornamental grasses used in Brazilian landscaping: Imperial zoysia grass (Zoysia japonica 'Imperial'), zoysia grass (Zoysia japonica) and St. Augustine grass (Stenotaphrum secundatum). The experimental design was entirely randomized in a factorial scheme 33 (three grass species: Zoysia japonica 'Imperial', Zoysia japonica and Stenotaphrum secundatum; in three water stress conditions: under full sun, with and without irrigation, and under greenhouse conditions without irrigation) with four replications per plot. The irrigation was performed using microsprinklers with a flow of 0.28 L s-1, and the grasses of all plots were mowed monthly. The evaluations were executed monthly, before mowing the grass, in the beginning of each season, that means, in October (for Spring evaluation), January (for Summer), April (for Autumn) and July (for Winter), considering the Brazilian climate conditions. The evaluated parameters were shoot height and total dry mass. The data were submitted to the variance analysis and the means were compared by the Tukey test at 5% confidence level. The grasses grown under greenhouse conditions, without irrigation, showed higher height and lower dry mass weight averages, what possibly indicates that the plants etiolated. The grasses grown under full sun, either with or without irrigation, showed a similar plant development. The S. secundatum species showed greater tolerance to water stress in October, month that followed the longest dry period. The total dry mass was gradually reduced during the experiment for all grasses grown under greenhouse conditions without irrigation; however, a great general tolerance to water stress was observed for all grasses because all of them survived along nine months without irrigation.

Growth of euterpe oleracea seedlings under different color nets and light conditions

Euterpe oleracea, a native palm to the Amazon, has recognized trading importance because of its fruits and heart of palm. However, it still requires general information on its propagation and cultivation. As light is essential for plant growth, this work aimed to study the effect of different color nets and light conditions on the initial growth of E. oleracea, with the objective to obtain high quality seedlings. The experiment was conducted in Jaboticabal County, São Paulo State, Brazil. The experimental design was entirely randomized, with six treatments (six light conditions: red net with 50% of shading - red Chromatinet®; blue net with 50% of shading - blue Chromatinet®; black nets with 70, 50 or 30% of shading; and full sun) and six replications (six evaluation periods: 30, 60, 90, 120, 150 and 180 days after the beginning of the experiment). Each plot consisted of four pots with one plant per pot, resulting in 144 plants. Seedling growth was monthly evaluated by collecting four plants per replication until the end of the experiment. Shoot length, root length, stem diameter, leaf number, leaf area and root and shoot dry matter were evaluated. The best quality seedlings of E. oleracea were obtained when they were cultivated under the black net with 50% of shading.

Crescimento, produtividade, acúmulo e exportação de nutrientes em cultivares de batata (Solanum tuberosum L.)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Características anatômicas foliares e controle químico em pós-emergência de Brachiaria decumbens e Brachiaria plantaginea

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Épocas de adubação nitrogenada na cultura do milho e sua influência na cultura subsequente, girassol, em sistema de semeadura direta

Pós-graduação em Agronomia (Agricultura) - FCA

Utilização agropecuária do sorgo de guiné e efeitos na cultura da soja e atributos químicos do solo

Pós-graduação em Agronomia (Agricultura) - FCA

Crescimento, alocação de recursos e requerimento de nutrientes em Heteranthera reniformis Ruiz e Pav

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)