Outplanting performace of eucalyptus clonal cuttings produced in different containers and substrates

The objective of this work was to evaluate the outplanting growth of Eucalyptus grandis e E. saligna clones, produced by cuttings in tubes (50cm³) and in pressed blocks (40x60x07cm) - 175 cm³/ seedlings, with different substrates (BT - sugarcane bagasse+sugarcane filter cake; AR - carbonized rice hull + eucalyptus bark; TF - peat). The experiment was arranged in a randomized block design, in a 2x7 factorial (2 clones and 7 treatments), with four replicates with 25 plants. Survival was evaluated two months later. Plant growth was monitored through height and ground level diameter at 20, 40, 60, 120 and 180 days after outplanting. To evaluate the effect of the containers on stem and root biomass in both clones, 180 days after outplanting, the cuttings grown in BT substrate with fertilizer were selected. One plant per plot of each clone, grown in tubes and in pressed blocks was selected. The E. grandis and E. saligna cuttings grown in pressed blocks with sugarcane bagasse+sugarcane filter cake presented greater height and diameter after out planting. Both clones presented larger root, bark, log and branch biomass production in plants produced in the block system. Cuttings of E. saligna grown in pressed blocks showed 80% most wood biomass 180 days after outplanting, compared to that grown in tubes. In E. grandis, the differences in diameter and height, in function of the cutting production system, decreased along time, while in E. saligna these differences increased along the evaluation period.

Efeito do vigor de sementes de soja sobre o seu desempenho em campo

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Manejo hídrico em viveiro e uso de hidrogel na sobrevivência pós-plantio de Eucalyptus urograndis em dois solos diferentes

O trabalho teve como objetivo avaliar a sobrevivência do clone H13 de Eucalyptus urograndis sob dois manejos hídricos de viveiro, plantados em dois solos, com e sem a adição de polímero hidroabsorvente (hidrogel). O plantio foi realizado em vasos mantidos em estufa, com dois tipos de solo: um arenoso e outro argiloso. Cada vaso recebeu 2,5 L de solo, um litro de água e o hidrogel na proporção de 0,4 g vaso-1 (120 mL de gel). O delineamento experimental adotado foi o inteiramente casualizado, com três repetições. Os sintomas de estresse, nos vários níveis avaliados, sempre se manifestaram primeiro nas plantas no solo argiloso, de modo mais acentuado naquelas que foram mantidas sem estresse de água na fase de viveiro. Isso garantiu que as plantas sobrevivessem por um período menor sem água, variando de 14 a 20 dias (com e sem hidrogel, respectivamente), enquanto, no solo arenoso, a sobrevivência foi maior, de 29 a 34 dias (com e sem hidrogel, respectivamente). Apesar da não significância estatística, os resultados com o hidrogel possibilitam, em ambos os solos, maior flexibilidade operacional na intervenção com novas irrigações.

Crescimento e produtividade da mamona de porte baixo em diferentes espaçamentos e populações de plantas

It is necessary to establish adequate row spacings and plant populations for recently developed short height castor (Ricinus communis L) cultivars. This work aimed to evaluate the growth, yield components, and yield of short castor cultivar IAC 2028 as affected by row spacing and plant population, in summer cropping season. The experiments were carried out in 2007/08 and 2008/09 cropping seasons, in Botucatu County, São Paulo State, Brazil. A randomized complete block design in a split-plot scheme with four replications was used. Treatments assigned to plots were four row spacing (0.45, 0.60, 0.75, and 0.90m) and subplots were assigned to four levels of plant populations (25000, 40000, 55000, and 70000 plants/ha). The increase of plant population decreased plants survival rate, shoot dry weight, stem diameter, number of racemes per plant, number of fruits per raceme, and 100-grains weight. In higher plant populations, the best arrangement of plants, provided by the narrower row spacing (0.45m), promoted higher grain and oil yields. Increasing plant population increased grain and oil yields only when was used the narrower row spacing.

Alterações morfoanatômicas em plantas de Lithraea molleoides (Vell.) Engl. submetidas ao alagamento

Flooding effects in Lithraea molleoides plants were studied. Young plants were kept under drained and flooded soil over a period of 35 days. For growth and development analyses, the length and diameter of stem and main root and the dry weight of roots, stem, and leaves were measured. For anatomical studies, sections of fresh and fixed roots, stem bases and leaves were made using standard procedures in vegetal anatomy. The stress reduced the dry weight increment of plants without causing the death of roots or the abscission of leaves. In the stem base, flooding induced the hypertrophy of lenticels and the increase of intercellular space and reduction lower starch contents, in the cortex. Plants flooded displayed greater percentage of cortical intercellular space in the secondary roots and lower investment in secretory structure formation in the stem base. It can be suggested that flooding reduced the recourses allocation to growth. These recourses could be used in morphological alterations, such as hypertrophied lenticels and increase of intercellular spaces, that could contribute to plants survival during stress period, probably, due maintenance of aerobic respiration.

Porta-enxertos, concentrações de potássio na resistência à didymella bryoniae e relações fisiológicas do meloeiro

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Acidovorax citruli: genetic analyses and protocol for its detection in seeds

Bacterial fruit blotch of cucurbits (BFB), caused by the seed borne Gramnegative bacterium Acidovorax citrulli is a serious threat to cucurbit industry worldwide. Since late 1980`s after devastating outbreaks in watermelon fields in southern United States, BFB has spread worldwide and has been reported in other cucurbit crops such as melon, pumpkin, cucumber and squash. To date, there is evidence for the existence of at least two genetically and pathogenically distinct populations of A. citrulli. In Brazil, the first report of BFB was in 1991, in a watermelon field in São Paulo. Although widespread in the country, BFB has been a major problem to melon production. More precisely, BFB has caused significant yield losses to melon production in northeastern Brazil, which concentrates > 90% of the country`s melon production. Despite the management efforts and the recent advances in A. citrulli research, BFB is still a continuous threat to the cucurbit industry, including seed producers, growers and transplant nurseries. To better understand the population structure of A. citrulli strains in Brazil, and to provide a basis for the integrated management of BFB, we used pulsed-field gel electrophoresis (PFGE), multilocus sequence analysis (MLSA) of housekeeping and virulence-associated genes and pathogenicity tests on different cucurbit seedlings to characterize a Brazilian population of A. citrulli strains from different hosts and regions. Additionally, we conducted for the first time a comparative analysis of the A. citrulli group I and II population at genomic level and showed that these two groups differ on their genome sizes due to the presence of eight DNA segments, which are present in group II and absent in group I genomes. We also provide the first evidence to suggest that temperature might be a driver in the ecological adaptation of A. citrulli populations under nutrient-rich or -depleted conditions. Finally, in order to improve the routine detection of A. citrulli on melon seedlots, we designed a new primer set that is able to detect the different Brazilian haplotypes, thus minimizing the risk of false-negatives on PCR-based seed health testing.

Variabilidade genética em progênies de polinização aberta de Eucalyptus urophylla

Pós-graduação em Ciência Florestal - FCA

Subdoses de glyphosate no desenvolvimento de espécies arbóreas nativas

Recovery of degraded areas aims to provide the degraded environment favorable conditions for restructuring in an environment that is unable to regenerate itself and planting of tree seedlings is one of the effective ways to extend this process. However, native tree species have slow growth rate which increases the seedlings production time as well as decreases their competitiveness with weeds in areas of forests deployment. The aim of this study was to evaluate the effects of glyphosate reduced rates application on Psidium cattleyanum (yellow guava), Citharexylum myrianthum (pau-viola) and Cedrela odorata (cedro) seedlings development by analyzing its morphophysiological parameters. The experiment was carried out in greenhouse conditions and the experimental units consisted of one plant were conducted in 2.5L plastic pots and arranged in a completely randomized design with six replications. Treatments consisted of glyphosate application at 0, 7.5, 15, 30 and 60 g ha(-1) using Scout (R) commercial formulation. Treatments application on these species seedlings was realized 120 days after seeds germination. Visual evaluations of plants phytotoxicity were realized at 7, 14 and 21 days after treatments application and plants survival, stomatal conductance, height, stem diameter and dry mass of shoots were evaluated 90 days after treatments application. Different doses of glyphosate did not cause plants phytotoxicity. Already, 30 and 60 g ha(-1) of glyphosate provided greater increases in height, stem diameter and dry mass of shoots for Citharexylum myrianthum and Psidium cattleyanum, respectively.

Qualidade da operação de semeadura de uma semeadora adubadora de plantio direto em função do tipo de martelete e velocidade de deslocamento

The current paper had as its objective to analyze the precision planter's operational performance according to five different displacement velocities and two types of jumpers for planting no-tillage corn. The utilized experimental delineation consisted of blocks at random with parcels subdivided in factorial scheme 2x5, two types of jumpers (4 and 5 staples) and five different displacement velocities (3.0; 4.5; 5.0; 7.0 e 9.0 km h-1) with four repetitions and by applying the average comparation test, as for the jumpers effects as for the displacement velocities effects, to the significance level of 5%. It was evaluated the data concerned to the longitudinal distribution of plants, average number of days for the emergence of seedlings, initial and final stand of plants, survival indices, mechanical harm on seeds, germination tests and grain production. It was also observed the planter displacement velocity effect of on variables as: longitudinal distribution of plants, average number of days for the emergence of seedlings, initial and final stand of plants, mechanical harm and yield. The survival indice of plants were high for all the studied velocities and jumpers. Among the studied velocities, the one of 5.0 km h-1 presented the highest yield to both types of jumpers.

Búsqueda de nuevos extractos y compuestos obtenidos a partir de plantas del centro de Argentina con acción inhibidora de enzimas asociadas a patologías y a la supervivencia de organismos perjudiciales. Search for new extracts and compounds obtained from plants of central Argentina with inhibitoryactivity on enzymes associated with diseases and survival of harmful organisms.

La inhibición en la actividad de ciertas enzimas esenciales puede generar disturbios en la fisiología de algunos organismos como insectos, plantas y microorganismos y en muchos casos puede conducir a su muerte. Por otro lado, la inhibición de estas proteínas logra modificar factores implicados en la manifestación de determinadas enfermedades. Entre las enzimas que muestran estas características podemos mencionar a tirosinasa, p-hidroxifenilpiruvato dioxigenasa (HPPD) y acetilcolinesterasa (AChE). Debido a la necesidad de nuevas drogas con acción inhibidora de las mencionadas enzimas,los investigadores están explorando el mundo vegetal con el fin de obtenerlas,ya que se ha comprobado que las plantas son capaces de sintetizar esta clase de moléculas. Plantas nativas de nuestra región presentan esta propiedad. Continuando con la búsqueda de compuestos bioactivos obtenidos de plantas, se propone en este proyecto obtener nuevos agentes naturales altamente efectivos en inhibir las nombradas enzimas a partir de 100 plantas nativas de la región central de Argentina. Los compuestos aislados pueden ser utilizados directamente o servir como modelo para la síntesis de análogos. En primer lugar se determinará la efectividad de los extractos obtenidos a partir de las plantas seleccionadas como inhibidores de HPPD (utilizando el método del enol-borato) con el fin de seleccionar el más potente. A partir de este extracto y de aquellos seleccionados como más potentes en inhibir tirosinasa y AChE se aislarán, mediante aislamiento bioguiado, e identificarán el/los compuesto/s responsables. Este proceso será llevado a cabo por técnicas cromatográficas y espectroscópicas y el seguimiento de actividad se realizará mediante el método de enol-borato, dopacromo y Ellman para HPPD, tirosinasa y AChE,respectivamente. Posterior a determinar el nivel de actividad (IC50) de cada compuesto aislado se estudiará el posible efecto sinergista que pudieran ejercer al combinarlos entre ellos (si más de un compuesto es aislado de una planta) y con compuestos comerciales. Si los resultados muestran que los extractos ensayados y los metabolitos activos presentes en ellos exhiben alta efectividad en inhibir las enzimas, ellos pueden surgir como agentes terapéuticos eficaces para el tratamiento de ciertas enfermedades que las involucran y de esta manera mejorar la calidad de vida de los pacientes afectados. Estos productos pueden dar lugar a las compañías farmaceúticas a producir drogas no convencionales como nuevas alternativas medicinales. Por otro lado estas sustancias pueden derivar en novedosos herbicidas, antimicrobianos o insecticidas.Dado que todas las plantas propuestas crecen fácilmente en Argentina, la producción de estos medicamentos significaría nuevas fuentes laborales para nuestro país. El hecho de poder obtener y posteriormente utilizar estos productos aumenta en forma sustancial el aprovechamiento que podemos darle a nuestra rica flora nativa.

Plant latex and first-instar monarch larval growth and survival on three North American milkweed species

First-instar larvae of the monarch butterfly, Danaus plexippus, a milkweed specialist, generally grew faster and survived better on leaves when latex flow was reduced by partial severance of the leaf petiole. The outcome depended on milkweed species and was related to the amount of latex produced. The outcome also may be related to the amount of cardenolide produced by the plants as a potential chemical defense against herbivory. Growth was more rapid, but survival was similar on partially severed compared with intact leaves of the high-latex/low-cardenolide milkweed, Asclepias syriaca, whereas both growth and survival were unaffected on the low-latex/low-cardenolide milkweed A. incarnata. On the low-latex/low-cardenolide milkweed A. tuberosa, both growth and survival of larvae were only marginally affected. These results contrast sharply to previous results with the milkweed, A. humistrata, in Florida, which has both high latex and high cardenolide. Larval growth and survival on A. humistrata were both increased by partially severing leaf petioles. Larval growth rates among all four milkweed species on leaves with partially severed petioles were identical, suggesting that latex and possibly the included cardenolides are important in first-instar monarch larval growth, development, and survivorship.

Analysis of long-term light-trap data for Helicoverpa spp. (Lepidoptera : Noctuidae) in Australia: the effect of climate and crop host plants

Regression analyses of a long series of light-trap catches at Narrabri, Australia, were used to describe the seasonal dynamics of Helicoverpa armigera (Hubner). The size of the second generation was significantly related to the size of the first generation, to winter rainfall, which had a positive effect, and to spring rainfall which had a negative effect. These variables accounted for up to 96% of the variation in size of the second generation from year to year. Rainfall and crop hosts were also important for the size of the third generation. The area and tonnage of many potential host crops were significantly correlated with winter rain. When winter rain was omitted from the analysis, the sizes of both the second and third generations could be expressed as a function of the size of the previous generation and of the areas planted to lucerne, sorghum and maize. Lucerne and maize always had positive coefficients and sorghum a negative one. We extended our analysis to catches of H. punctigera (Wallengren), which declines in abundance after the second generation. Winter rain had a positive effect on the sizes of the second and third generations, and rain in spring or early summer had a negative effect. Only the area grown to lucerne had a positive effect on abundance. Forecasts of pest levels from a few months to a few weeks in advance are discussed, along with the improved understanding of the seasonal dynamics of both species and the significance of crops in the management of insecticide resistance for H. armigera.

Survival and development of Helicoverpa armigera (Hubner) (Lepidoptera : Noctuidae) on neem (Azadirachta indica A. Juss) leaves

The survival, development and feeding responses of Helicoverpa armigera (Hubner) on neem (Azadirachta indica A. Juss) leaflets were evaluated under choice and no-choice conditions. Neem leaflets provided to starving fourth-instar larvae were chewed, but larvae expectorated most of the material. The weight of surviving larvae decreased and no fourth instars completed development on neem leaflets alone. Larvae resumed feeding when transferred to cotton leaves after 5 days of feeding on neem leaflets. Fourth instars strongly discriminated between neem leaflets and cotton leaves when offered a choice. Early sixth instars decreased in weight and had delayed development when feet only on neem leaflets. Mure than one-half lived for more than 2 weeks and some completed development to adults. Neem is an unacceptable non-host plant species for H. armigera.

It's the first bites that count: Survival of first-instar monarchs on milkweeds

Mortality of first instars is generally very high, but variable, and is caused by many factors, including physical and chemical plant characters, weather and natural enemies. Here, a summary of detailed field-based studies of the early-stage survival of a specialist lepidopteran herbivore is presented. First-instar larvae of the monarch butterfly, Danaus plexippus, a milkweed specialist, generally grew faster and survived better on leaves when latex flow was reduced by partial severance of the leaf petiole. The outcome depended on milkweed species, and was related to the amount of latex produced, as well as other plant characters, such as leaf hairs, microclimate and concentration of secondary metabolites. Even for a so-called 'milkweed specialist', larval performance and survival appears to be related to the concentration of cardenolides produced by the plants (a potential chemical defence against herbivory). This case study of monarchs and milkweeds highlights the need for field-based experiments to assess the effect of plant characters on the usually poor survival of early instar phytophagous insects. Few similar studies concerning the performance and survival of first-instar, eucalypt-specific herbivores have been conducted, but this type of study is considered essential based on the findings obtained using D. plexippus.