Janaína Dartora

Inoculation with Azospirillum, associated with nitrogen fertilization in maize

The biological nitrogen fixation is an alternative to supply the nitrogen needed for maize. The objective of this study was to evaluate the development and yield of maize in response to inoculation with Azospirillum associated with nitrogen fertilization. We conducted two field experiments in the summer harvest, the first in the 2000/2001 crop year in the region of Marechal Cândido Rondon, under conventional tillage, and second in the 2002/2003 agricultural year in the region of Cascavel, under no tillage. The experimental design in both experiments was a randomized complete block, with four replications, 2x2x2 factorial, with two levels of nitrogen at sowing (zero and 20 kg ha-1), two levels of inoculum (zero and 200 g ha-1) and two levels of nitrogen in topdressing (zero and 100 kg ha-1). There was evaluated the height of ear insertion, total plant height, leaf N content, shoot dry biomass and grain yield. The height of ear insertion and total plant height were not influenced by the factors under study. Nitrogen fertilization at sowing increased the leaf N content, causing the opposite effect when combined with inoculation. Inoculation with Azospirillum in the absence of nitrogen, provide productivity increases of 15.4% and 7.4% for 2000/2001 and 2002/2003 crops, respectively. The inoculation provided productivity similar to that obtained with 100 kg ha-1 in topdressing in crop 2000/2001, while in association with the topdressing, reduced productivity and shoot dry biomass in crop 2002/2003.

Adubação nitrogenada associada à inoculação com Azospirillum brasilense e Herbaspirillum seropedicae na cultura do milho

Bacteria of the genera Azospirillum and Herbaspirillum have the ability to fix atmospheric nitrogen (N) and promote plant growth. The aim of this study was to evaluate the development and productivity of maize in response to inoculation with A. brasilense and H. seropedicae associated to N fertilizer. The experimental design was a randomized complete block with four replications and treatments arranged in a 4 x 5 factorial. The treatments consisted of inoculation of seeds (control, strain of A. brasilense - Ab-V5, strain of H. seropedicae - SmR1 and combination SmR1+Ab-V5) and N levels (0, 40, 80, 120 and 160 kg N ha-1). The basal diameter of stem, plant height, shoot dry weight and leaf area were evaluated at the vegetative and reproductive stages, and productivity. Nitrogen fertilization promoted the development of the crop until maximum nitrogen dose studied. The combined inoculation of strains of A. brasilense (Ab-V5) and H. seropedicae (SmR1) provided increments of 12% dry weight of shoot and 7% in grain yield compared to the control, indicating benefits of the combination of diazotrophic bacteria that interact differently with the plant.

Growth and yield of corn hybrids in response to association with Azospirillum brasilense and nitrogen fertilization

There is a growing interest in optimizing the positive effects of the association between Azospirillum bacteria and corn crop in order to reduce the use of nitrogen fertilizers. This study aimed to evaluate the inoculation efficiency of an A. brasilense-based commercial product in association with different rates of nitrogen fertilization in two corn genotypes. The experiment was arranged in a 2 x 2 x 5 factorial randomized block design, with four replications. The treatments consisted of two corn hybrids (30F53 and CD386); with and without inoculation with a commercial product based on A. brasilense and five nitrogen rates (0, 40, 80, 120 and 160 kg ha-1). The variables plant height, basal stem diameter, leaf area, shoot dry matter, leaf nitrogen content, length and diameter of the cob, weight of 100 grains and grain yield were evaluated. Inoculation with A. brasilense provided increases of 11 and 12% in leaf area and shoot dry matter, respectively. There were differences in the response of the corn hybrids for most variables and the increase in nitrogen supply provided increments in the growth and yield of corn.

Efeito antifúngico de extratos alcoólicos de própolis sobre patógenos da videira

The objective of this work was to verify the in vitro effect of alcoholic extracts of propolis (AEP) on the germination of spores of Phakopsora euvitis and Pseudocercospora vitis, and also on the mycelial growth and sporulation of Elsinoe ampelina. For the germination assay the AEP was used at concentrations of 0.025; 0.05; 0.1; 0.2; 0.25 and 0.5%. Distilled water, ethanol at 0.35% and the fungicide azoxystrobin were used as control treatments. For mycelial growth and sporulation the concentrations 0.05; 0.1; 0.2; 0.4; 0.5 and 1.0% of AEP were used. The control treatments were potato-dextrose-agar (PDA) medium, PDA + 0.7% ethanol and the fungicide azoxystrobin. The results showed that AEP has a low in vitro antifungal activity against P. euvitis, P. vitis and E. ampelina, for the tested concentrations.

Análise de crescimento e produtividade do pak choi cultivado sob diferentes doses de nitrogênio

O objetivo deste trabalho foi avaliar a influencia de diferentes doses de nitrogenio no crescimento e produtividade do pak choi. O experimento foi conduzido, em cultivo protegido, de outubro a novembro de 2007, em Marechal Cândido Rondon, PR. O delineamento experimental foi de blocos casualizados, com cinco tratamentos (0, 60, 105, 150 e 195 kg ha-1 de N) e quatro repeticoes. O nitrogenio foi aplicado em tres diferentes epocas (transplantio, 7 e 14 dias apos o transplantio). Foram realizadas cinco coletas das plantas, semanalmente, avaliando-se a producao de massa da materia seca e area foliar, para obtencao das taxas de crescimento absoluto e relativo, taxa assimilatoria liquida, razao de area foliar e area foliar especifica. Na colheita, foram avaliados altura da planta, diâmetro e materia fresca da parte aerea e produtividade. Incrementos na adubacao nitrogenada ate a dose de 195 kg ha-1 proporcionam incrementos no crescimento e produtividade do pak choi.

Growth and production of Malaysia cabbage under the nitrogen fertilization.

The aim of this work was to evaluate, through the growth analysis, the effects of nitrogen doses on the development of Brassica campestris var. chinensis (Pak Choi). The experiment was carried out in a greenhouse, from October to November, 2007, in Marechal Cândido Rondon, Parana. The experimental design was the randomized block, with five treatments (0, 60, 105, 150 and 195 kg ha -1 of N) and four replications. The hybrid used was Chouyou . The nitrogen was equally applied in three times, when in transplantation, and at seven and 14 days after the transplantation. The dry mass production, and the foliage area were weekly evaluated reaching the following indices of growth: relative and absolute growth rate, net assimilation rate, leaf area ratio, and specific leaf area. The fresh mass of the aerial part was also evaluated in the last collection. The increase of nitrogen fertilization positively affects the growth parameters, and provides an increased production with emphasis on the dose of 195 kg ha -1 of N.