Henrique Soares Koehler

Rendimento de milho em área de integração lavoura-pecuária sob o sistema plantio direto, em presença e ausência de trevo branco, pastejo e nitrogênio

This field experiment was carried out at the Fundacao Agraria de Pesquisa Agropecuaria [Agrarian Foundation for Agricultural and Cattle Research] (FAPA), in Guarapuava, State of Parana, Brazil, during the growing seasons of 1999 and 2000. The objective was to verify residual effects of nitrogen fertilization on maize crop under a no tillage system, in presence and absence of white clover and grazing animals. The experimental layout was a completely randomized block design with three replications. The treatments were arranged in split-plots. Four N rates (N-TI = 0, 100, 200, and 300 kg ha-1 of N) were previously applied on the main plots during the winter season, while the treatments of the sub-plots consisted in combinations of presence and absence of white clover and grazing (CT = with clover; ST = without clover; CP = with grazing, and SP = without grazing). During the summer each sub-plot that had been prepared during the winter was cultivated with corn which received five N rates (N-TV = 0, 60, 120, 180, and 240 kg ha-1 of N) top dressed. The maximum re-growth efficiency of winter culture plants occurred eighteen days after the animals had been removed from the plots, obtained with 231 kg ha-1 of N (N-TI). The areas CP/N-TI presented higher corn yields than the SP plots, although these differences were not statistically significant. The areas without N-TI produced most in the SP subplots. On plots that had received 300 kg ha-1 of N N-TI there was no response of corn to the N-TV, confirming the residual effect of N-TI. The conclusion was drawn that the interaction between grazing and N-TI contributes to nitrogen nutrition in maize.

Período crítico de interferência das plantas daninhas na cultura do feijoeiro-comum em sistema de semeadura direta

A field experiment was carried out at the Training Farm of Ponta Grossa State University, in Ponta Grossa-PR, Brazil, during the 1996/1997 growing season to determine the critical period of weed interference in the common bean under direct seeding system, associated with the phenological stage of the common bean growth. The experimental design was a randomized complete block arranged in a 2 x 8 factorial, with four replications. The 16 treatments tested resulted from a combination of two groups of weed interference treatments : (a) relative weedy period, and (b) relative weed-free period, in seven physiological stages of bean growth: V2, V3, V4, R5, R6, R7 and R8, and a check plot with the crop in coexistence with the weeds. The experiment was carried out on an area 8 years under direct seeding system. Sowing, fertilization, and insect and disease control were performed according to the technology recommended for the crop. The weed interference critical period occurred between the V4 and R6 phenological stages of growth, and bean yield was reduced in 71% when the crop was maintained in coexistence with the weeds during all the crop cycle. Regarding weed composition, the dicotyledons class of weed represented 61.3%, being Bidens pilosa and Richardia brasiliensis the most prevalent, with 30.6% and 16.6%, respectively. Monocotyledons represented 38.7%, and Digitaria horizontalis and Brachiaria plantaginea, were the most prevalent, with 23.6% and 14.3%, respectively.

Plant regeneration from cotyledonary explants of Eucalyptus camaldulensis

Breeding methods based on genetic transformation techniques need to be implemented for Eucalyptus camaldulensis to shorten the long breeding cycles and avoid manipulation of adult trees; that requires the development of plant regeneration protocols enabling development of plants from transformed tissues. The present work aimed to optimise the regeneration process already established for the species. Cotyledonary leaves of E. camaldulensis were cultured in MS medium supplemented with naphthaleneacetic acid (NAA) and 6-benzylaminopurine (BAP) combinations. The most efficient treatment for bud indirect regeneration (2.7 µmol L-1 NAA and 4.44 µmol L-1 BAP) was used for further experiments. When explants were kept in the dark during the first 30 days, the percentage of explants forming calluses increased and explant necrosis was reduced in comparison with light-cultured explants. Mineral medium modifications were compared and half-strength MS mineral medium turned out to be as efficient as full-strength medium, producing 54% and 47% of explants with buds, respectively. For shoot elongation, MS medium with half-strength nitrate and ammonium salts, and 0.2% activated charcoal yielded rooted shoots 1 to 8 cm high after one month. The procedure is an efficient protocol for E. camadulensis plant regeneration, reducing the stages necessary for the obtention of complete plants.

Antecipação da colheita na qualidade fisiológica de sementes de soja

HARVEST ANTICIPATION ON THE PHYSIOLOGICAL QUALITY OF SOYBEAN SEEDS The harvest delay starting from the physiological maturity has negative influence in soybean seed quality, due to the exposure to unfavorable environmental conditions. Usually, farmers wait for the decrease in seed moisture levels to begin the harvest process as soon as possible. This research had the objective to analyze the influence of harvest anticipation of soybean seeds at different moisture contents on the physiological quality of seeds produced, in search of better seed moisture contents for earliest harvest considering seed vigor and germination. Then trials were carried out with two soybean cultivars, during 2006/2007 crop year and seeds of each cultivar were harvested at R8 stage, at different seed moisture levels, beginning the operation at 28.5% of water and ending at 14.0%. Quality evaluation was made twice: in April, in order to analyze the initial quality of the samples and, in October, to analyze the influence of storage. In each evaluation period, seed moisture content, germination and tetrazolium viability and vigor were assayed. According to the results obtained, the following conclusion can be drawn: soybean seed harvest time can start at seed moisture content below 22.9%.

Micropropagação de Cabralea canjerana

n Cabralea canjerana (Vell.) Mart. (Meliaceae) (icanjaranai) is a native tree of economic importance in Brazil. The storage of seeds is of short duration and it is therefore necessary to establish a protocol for micropropagation of this species. In this work, multiplication experiments were carried out using nodal segments, excised from in vitro germinated plants. The segments were inoculated in MS or WPM culture medium, supplemented with 6-benzylaminopurine (BAP) and/or 2-isopentenyladenine (2-iP) at 2.5 or 5 µM. Micro-cuttings were taken from new shoots developed from the seeds and used in a rooting experiment using a culture medium with half-strength MS medium (MS/2) supplemented with indolbutyric acid (IBA) (0, 2.5 and 5 µM). After 7 days in this medium, they were transferred to MS/2 medium without auxin under light. During the multiplication phase, the MS culture medium was more suitable for the multiplication of C. canjerana than WPM medium. The nodal segments cultured in the presence of 2.5 µM BAP showed the best result, with a multiplication rate of 1.77 per month on MS medium. The rooting of the microcuttings was 87.5% when they were kept in the presence of 5 µM IBA for 7 days. An acclimatization rate of 90% was achieved after 30 days in the greenhouse. In conclusion, the micropropagation of C. canjerana from nodal segments of plantlets is possible for this species.

IN VITRO MULTIPLICATION OF Swietenia macrophylla KING (MELIACEAE) FROM JUVENILE SHOOTS

Big-leaf mahogany (Swietenia macrophylla King) is an important species for timber production that is considered the most valuable in the world. For this reason its exploitation is indiscriminate and leads this species to the risk of extinction. Moreover, mahogany is difficult to regenerate naturally and, when used in reforestation programs, plants are severely damaged by the shoot-borer (Hypsipyla grandella Zellar). This work aimed at developing the multiplication stage of micropropagation of Swietenia macrophylla King using juvenile material. After desinfestation, seeds were germinated in MS solid culture medium. Shoot formation from seeds occurred during five months, giving 5.54 nodal segments per seed. These explants were excised, each containing one axillary bud, and transferred on multiplication media. Four experiments with cytokinins were conducted, using media supplemented with 6-benzylaminopurine (BAP) (2.5 to 50.0 µM), 2isopentenyladenine (2-iP) (0; 1.1 to 8.8 µM), combinations of BAP (0; 2.5 to 50.0 µM) and 2-iP (2.2 µM). For the first treatments the basal culture medium was MS medium and in the last one MS and QL media were used in separate experiments. When BAP was tested alone, the maximum point of multiplication rate average was obtained on medium containing 23.61 µM, while 2-iP did not induce bud multiplication. On QL culture medium supplemented with the combinations of BAP (0; 2.5; 5.0; 10.0 e 20.0 µM ) and 2-iP (2.2 µM), there was no multiplication. The maximum point of multiplication rate average was 5.7 µM, obtained when the MS culture medium was supplemented with 18.51 µM BAP and 2.2 µM 2-iP.

Análise da viabilidade econômica da produção de leite a pasto e com suplementos na região dos Campos Gerais - Paraná

Aiming to evaluate the profitability of milk production under an integrated dairy-crop system, on experiment was carried out at a commercial farm, of Parana State, from July 2004 up to April 2005. A completely randomized block design, with four treatments, corresponding to different supplementation levels, with three replicates was applied. Treatments were pastures supplemented with 20%, 45%, 65% and 100% of supplementation (total diet calculated to give maintenance and milk production of 28kg/cow per day). The experimental area contained 32.4 hectares, being 22.4 hectares used during winter, composed of a mixture of annual ryegrass (Lolium multiflorum L.) and black oat (Avena strigosa Schreb), divided into twelve paddocks. During summer an area of 10 hectares was used, with Kikuyo (Pennisetum clandestinum) also divided in 12 paddocks. Three Holstein and one Jersey cows were used in each experimental unit as testers animals. The grazing system was continuous, with variable stocking. Put-and-take animals were used to control ward height, maintained around 20cm. Individual milk production was evaluated twice a week and percentage of fat, protein and somatic cell count were evaluated weekly. The economic analysis was proceeded using the methodology proposed by the Milk Cost Follow Up System of Parana State. During the evaluation period, treatment 1 with 20% of supplementation showed the best results, with a total operational cost of R

Propagación vegetativa de quiri por intermedio de brotes epicórmicos

0.4635 liter-1 and net income of R

EFEITO DO ESTRESSE HÍDRICO SIMULADO COM NACL, MANITOL E PEG (6000) NA GERMINAÇÃO DE SEMENTES DE Erythrina falcata Benth

0.13 liter-1.

MINIESTAQUIA DE Sapium glandulatum (Vell.) PAX COM O USO DE ÁCIDO INDOL BUTÍRICO E ÁCIDO NAFTALENO ACÉTICO

cEmbrapa, Centro Nacional de Pesquisa de Florestas, Colombo-PR, Brazil. SUMMARY Epicormic shoots were induced in stumps and detached branches of adult Paulownia fortunei var. mikado plants to evaluate rooting potential. Stem cuttings obtained from shoots of stump were prepared with 12 cm in length and two leaves reduced to 78.5 cm² (10 cm diameter). Cuttings from shoots of branches were prepared with 8-10 cm in length, and two leaves reduced to 50 % of the original size. Anatomical analysis was performed to evaluate possible barriers to rhizogenesis. After disinfestation, indolebutyric acid (IBA) was applied (0, 500, 1,000, 1,500 and 2,000 mg L -1 ). Installation was made in plastic pots with a volume of 170 cm³ and 53 cm³, respectively for each type of cuttings, with fine vermiculite and carbonized rice hulls (1:1 v/v) as substrate. After 60 days in a greenhouse, cuttings from epicormic shoots of branches presented rooting (58.12 %) and the average length of the three longest roots/ cutting (4.76 cm) was higher than in cuttings from stumps. The highest number of roots/cutting (7.66) and percentage of cuttings with callus (27.50) was observed in cuttings from stumps. There were no anatomical barriers observed harming the roots formation in the two types of cuttings. The use of indolebutyric acid is not required to induce rooting.