Citocinina e potencial fisiológico de sementes de milho doce

O trabalho teve como objetivo avaliar diferentes concentrações de citocinina na manutenção do potencial fisiológico de sementes de milho doce antes e após o processo de envelhecimento acelerado. Sementes de milho doce, cultivar BR-400 (Super-Doce) foram submetidas à embebição em diferentes concentrações de citocinina (0, 50, 100, 150 e 200 mg L-1), Benzil Amino Purina (BAP), sob o delineamento experimental inteiramente casualizado. Após os tratamentos, avaliou-se a determinação do teor de água, teste de germinação, primeira contagem do teste de germinação, condutividade elétrica e lixiviação dos íons K, Ca e Mg e, em seguida foram submetidas ao envelhecimento acelerado seguido pelas mesmas determinações iniciais. Os dados obtidos foram submetidos à análise de variância e as médias comparadas pelo teste de Tukey

Identification of promising wheat genotypes for crossing

The objective of this study was to identify promising wheat genotypes from the IAPAR breeding program for crossesby multivariate techniques. Measures of dissimilarity between genotypes were obtained from multicategoric variables. To identifyclusters, Tocher optimization and UPGMA were used. The genotypes were divided into five diverging groups, indicating a widegenetic base of the wheat breeding program of the Agricultural Research Institute of Paraná (IAPAR). As indicated by the geneticdistance, crosses involving the cultivars IPR 85 and IPR 118 seem to be the most promising to increase genetic gains in both grainand flour quality as well as for agronomic parameters

Germination performance of grain sorghum hybrid seeds treated with bioregulator under water deficit

Water stress can reduce the speed and percentage of germination, damaging the development of seedlings. Thus it is necessary to find alternatives they can mitigate these effects. The plant growth regulators has been heavily used in agricultural production and can proporcionarum increase in the growth and development of plants. Thus, the objective of this study was to evaluate the germination performance of seeds of two hybrids of sorghum under simulated water stress, treated with plant growth regulator. The experimental design was completely randomized in a factorial 2 x 4, establishing itself as factors, two seed treatments (with and without plant growth regulator) and four water potential (0, -0.4, -0.8, -1.2 MPa) with four replications, separately for single hybrid grain sorghum: 1G100 and 1G233. Germination, the first count of germination, shoot and root length and dry matter of shoot and root were evaluated. Data were subjected to analysis of variance and means compared by Tukey test at 5% probability and regression analysis. The osmotic potential reduction to the level of -1.2 MPa reduced seed quality, however the application of plant growth regulator did not improve seed quality before the water stress. The plant growth regulator increased root length, dry weight of shoot and root of sorghum seedlings grow 1G233, in the absence of water deficit.Water stress can reduce seed germination speed and percentage, harming the development of seedlings. Thus, it is necessary to find alternatives that can mitigate these effects. Bioregulators have been intensively used in agricultural production and can provide increase in plant growth and development. Therefore, the aim of this work was to evaluate the germination performance of seeds of two grain sorghum hybrids under simulated water deficit treated with bioregulator. The experimental design was completely randomized in a 2 x 4 factorial scheme, with the following factors: two seed treatments (with and without bioregulator) and four osmotic potentials (0; -0.4; -0.8 and -1.2 MPa), with four replicates, separately for the following grain sorghum hybrids: 1G100 and 1G233. Germination, first germination count, shoot and root length and shoot and root dry matter were evaluated. Data obtained were submitted to analysis of variance and means were compared by the Tukey test at 5% probability and regression analysis. The reduction of the osmotic potential to the level of -1.2 MPa reduced the physiological quality of seeds; however, bioregulator application did not result in better seed quality under water stress. Bioregulator Stimulate® increased root length and shoot dry matter of seedlings of grain sorghum cultivar 1G233 in the absence of water deficit

Hydration methods and physiological potential of sweet corn seeds

The evaluation of the physiological potential of sweet corn seeds is fundamental in the production process, because the germination and vigor reflect the potential for storage, commercialization and use of these seeds. The choice of vigor tests with an adequate and efficient analysis methodology is fundamental to obtaining reliable results. In this sense, the objective of this study was to assess the physiological potential of sweet corn seeds after hydration using different moistening methods to increase water content to 20%. First, the lot of seeds was characterized as to its moisture content and initial physiological potential. Subsequently, two experiments were conducted, both under a completely randomized design. In the first experiment, different volumes of water on the filter paper sheets were assessed for seed hydration a method that uses a wet substrate. In the second, four hydration methods were evaluated: wet substrate (WS), humid atmosphere (HU), immersion in water (IW) and addition of the required amount of water (WR). A constant temperature of 25ºC was used in both experiments and then the moisture content and physiological potential of seeds were determined. The humid atmosphere method reduces the physiological quality of sweet corn seeds because it favors the deterioration and hence is unsuitable for the hydration of seeds of this species. The wet substrate method, in an amount equivalent to 2.5 times the paper mass, increased the water content of sweet corn seeds to 20%, achieving the desired degree of moisture without altering their physiological potential

Desempenho agronômico de genótipos de milho de segunda safra na região Norte do Paraná

The study aimed to evaluate the agronomic performance of maize genotypes sown in the second crop for the region of Londrina - PR. The experiment was conducted in the field at the Farm School, Universidade Estadual de Londrina-PR. We evaluated 13 genotypes of maize (2B710, 2B587, 2B688, 2C520, DAS8089, DAS9375, DAS8010, DAS8055, DAS9379, DAS9380, DAS9384, DKB390 and AG9010), seeded 09th of March 2007. The experimental design was a randomized complete block with four replications. We evaluated cycle, degree days, features fitometrics, broken and lodged plants, yield components and productivity. Data were subjected to analysis of variance and means were compared by Scott-Knott 5%. The genotypes showed higher than average productivity in the region. Therefore, the genotypes 2B710, 2C520, DAS8055, DAS8010 DKB390 and had the best performance in relation to agronomic characteristics fitometrics, yield components and productivity in the cultivation of second crop for the region of Londrina-PR.O trabalho teve como objetivo avaliar o desempenho agronômico de genótipos de milho semeados na safrinha para a região de Londrina – PR. O experimento foi conduzido a campo na Fazenda Escola da Universidade Estadual de Londrina-PR, avaliando 13 genótipos de milho (2B710, 2B587, 2B688, 2C520, DAS8089, DAS9375, DAS8010, DAS8055, DAS9379, DAS9380, DAS9384, DKB390 e AG9010), sob o delineamento experimental de blocos casualizados, com 4 repetições. Foram avaliados ciclo, graus dias acumulados até o florescimento, características fitométricas, plantas acamadas e quebradas, componentes de produção e a produtividade. Os dados foram submetidos à análise de variância e as médias comparadas pelo teste de Scott-Knott a 5%. Os genótipos avaliados apresentaram produtividade superior à média da região. Os genótipos 2B710, 2C520, DAS8055, DAS8010 e DKB390 apresentaram o melhor desempenho agronômico em relação às características fitométricas, os componentes de produção, e a produtividade no cultivo da safrinha para a região de Londrina-PR

SOURCES AND RATES OF NITROGEN ON THE NUTRITION AND PRODUCTIVE PERFORMANCE OF DETERMINATE GROWTH HABIT SNAP BEAN

Snap bean is a vegetable crop presenting high requirements of mineral nutrients, such as nitrogen (N). However, studies on the response of this crop to N fertilization are scarce, mainly with determinate growth habit genotypes, making it difficult to manage the nutrient supply. The aim of this study was to evaluate the nitrogen nutrition and the productive performance of determinate growth habit snap bean as a function of N sources and rates. The experiment was carried out in pots, under greenhouse conditions, in a Red Latosol with 36.60 g dm-3 of soil organic matter content. The cultivar ‘Macarrão rasteiro’ TopSeedâ was grown in a completely randomized design at factorial scheme 3x4, with four replications. It was studied three sources of N (urea, ammonium sulfate and sulfammoâ) and four rates (0, 40, 80 and 120 kg N ha-1), applied 20% at sowing time, 40% at 12 days after emergence (DAE) and 40% at 20 DAE of the seedlings. It was evaluated the N content of the index leaf and the N accumulation in shoots, the plant height at the end of the cycle and the number, total fresh mass, mean fresh mass and mean length of pods. The N content of the index leaf and N accumulation in shoots were linearly increased by the N rates, regardless of the N source, while the plant height and the pod’s characteristics were influenced by none of the factors studied.O feijão-vagem é uma hortaliça que apresenta elevada demanda por nutrientes minerais, dentre eles o nitrogênio (N). No entanto, são escassos os estudos de resposta da cultura à adubação nitrogenada, principalmente para cultivares de crescimento determinado, dificultando o manejo de fornecimento do nutriente. O objetivo deste trabalho foi avaliar a nutrição nitrogenada e o desempenho produtivo de feijão-vagem de crescimento determinado em função de fontes e doses de N. O experimento foi conduzido em vasos, sob condições de casa de vegetação, em Latossolo Vermelho com teor de matéria orgânica de 36,60 g dm-3. A variedade ‘Macarrão rasteiro’ TopSeedâ foi cultivada em delineamento experimental inteiramente casualizado com esquema fatorial 3x4, com quatro repetições. Estudaram-se três fontes de N (ureia, sulfato de amônio e sulfammoâ) e quatro doses (0, 40, 80 e 120 kg N ha-1), parceladas 20% na semeadura, 40% aos 12 dias após a emergência (DAE) e 40% aos 20 DAE das plântulas. Foram avaliados o teor de N na folha-índice, o acúmulo de N na parte aérea, a altura das plantas ao final do ciclo, o número, a massa fresca total, a massa fresca média e o comprimento médio das vagens. O teor foliar e o acúmulo de N na parte aérea das plantas foi aumentado linearmente com as doses, independente da fonte utilizada, enquanto a altura das plantas e as características relacionadas às vagens não foram influenciadas por nenhum dos fatores estudados

Produtividade, índice de vegetação e clorofila de trigo em resposta à inoculação com Azospirillum brasilense e adubação nitrogenada em cobertura

O objetivo foi avaliar os efeitos da inoculação de sementes de trigo (Triticum aestivum L.) com Azospirillum brasilense e doses de nitrogênio em cobertura no desempenho produtivo, índices de vegetação e clorofila e teores de nitrogênio na folha e no grão. Experimentos a campo foram conduzidos em delineamento experimental de blocos casualizados, esquema fatorial 2 x 5 com seis repetições. Avaliou-se a inoculação de sementes com Azospirillum brasilense (com e sem) e cinco doses de nitrogênio em cobertura (0, 30, 60, 90 e 120 kg ha-1), aplicadas por ocasião do perfilhamento. Foram avaliados: produtividade e massa de mil grãos, teor de nitrogênio na folha e grão, massa seca da parte aérea, índice de clorofila e de vegetação avaliados por ocasião do perfilhamento, elongamento do colmo e espigamento. Os dados foram submetidos à análise de variância, correlação e análise de regressão para doses, e comparação de médias pelo teste de Tukey a 5% para inoculação. O nitrogênio aplicado em cobertura no trigo cultivado após a soja não altera a produtividade, a massa de 1000 grãos e a massa seca da parte aérea, porém, o incremento das doses aumenta linearmente o teor de nitrogênio no grão e o índice de clorofila e de vegetação avaliado na fase de espigamento. A inoculação com Azospirillum brasilense aumenta o teor do nitrogênio no grão, mas não influencia as demais características avaliadas. O índice de vegetação por diferença normatizada (NDVI), avaliado no perfilhamento, elongamento do colmo e espigamento possui correlação positiva com a produtividade, quando avaliado no espigamento com o teor de nitrogênio da folha bandeira

Phosphorus priming influence on different quality of wheat cv. “Pardela” and “Gralha Azul” seeds

The seed priming allows the beginning of the metabolic processes necessary for the germination. Phosphorus is a macronutrient necessary for the growth and development of seedlings, since it participates in the structural components cell like the nucleic acid molecules. The objective was to evaluate the effect of priming and priming with phosphorus (P) on the physiological quality of wheat seeds with different levels of vigor. For the experiment, three lots of wheat seeds of Pardela cultivar, with different levels of vigor i.e. high, medium and low were used. The effect of priming with water and priming with different potential levels of phosphorus was evaluated: 0 (control), 0.10 %, 0.20 %, 0.30 %, 0.40 % and 0.50 % P. The first germination count, percentage of germination, abnormal seedlings, root and shoot length, and dry mass of the seedlings were determined. For the priming with water, the data were submitted to analysis of variance and the means compared by the Tukey test. In the study of the effect of the different concentrations of phosphorus, a variance and regression analysis was carried out, following the completely randomized design, in a factorial scheme 3x6. The Priming in water had significantly influenced all treatments, independently of the seeds vigor levels, increases in the percentage of normal seedlings obtained in the first count and also in the percentage of germination of the low and medium vigor lots, and the seedlings primed in water had significantly larger shoot length in the three different lots. Regarding the different concentrations of phosphorus, significant differences were observed only in the first count of the germination, which decreased with the increase of the phosphorus concentration and the length of the aerial part, which presented an inverse behavior, increasing with the highest levels of phosphorus. Significant interaction between the different vigor levels and phosphorus concentrations was observed only for the root length variable, where concave, linear and convex trends were observed for the high, low and medium vigor lots, respectively. Phosphorus solutions had the optimum role as priming source in promoting seed emergence and root development irrespective of quality seed

Nitrogen fertilization in the contents of secondary compounds in cassava cultivars

The production of chemical substances is a strategy of plants to defend against the attack of pest insects. The synthesis of secondary compounds in plants is influenced by genotype and cultural management, such as the use of nitrogen fertilizers. Thus, the objective of this work is to evaluate the effect of doses of nitrogen fertilizer over time on the production of secondary compounds in two industrial cassava cultivars. The experiment was carried out in a greenhouse (25 ± 5 °C) of Embrapa Soybean in Londrina, Paraná, with the cultivation of potted plants (4l) in a 2 × 4 × 3 factorial scheme, with five replications. Two genotypes of industrial cassava (‘Baianinha’ and ‘Caiuá’) and four different nitrogen doses (0, 30, 60, and 90 kg ha-1) were used, with sampling at 15, 30, and 45 d after fertilization. Nitrogen fertilization was performed 50 d after sprouting. In the apical leaves, the levels of rutin, caffeic, p-coumaric and ferulic acids were evaluated in a high performance liquid chromatograph (HPLC). Exploratory analyses were performed on the data variables to verify the assumptions for analysis of variance (ANOVA), such as the independence and normality of errors, homogeneity of treatment variances and non-additivity of the model (they were submitted to analysis of homogeneity and normality, respectively. After these tests, ANOVA and Tukey’s test (p ? 0.05) were performed. For the quantitative data concerning the N rates, regression study analyzes were performed. The Caiuá cultivar was found to have a higher ferulic acid content. The caffeic acid content decreased over time after the application of N in both cultivars. The rutin content in both cultivars did not increase with an increase in nitrogen dose. At a dose of 90 kg ha-1, both cultivars presented a lower p-coumaric acid content after 30 d