Cristina Rossetti

The importance to evaluate the final yield of the crop. The objective of this work was to estimate the linear relationships among growth variables, to evaluate groups of shoot and root variables by analyzing canonical correlations and the genetic distance among the three radish cultivars. The experimental design was a randomized block design, organized in a factorial scheme: three (radish cultivars) x seven (collection times of plants 13, 16, 19, 22, 25, 28 and 31 days after sowing), arranged in four replicates. The plants were collected at regular intervals of three days, starting on the thirteenth day after sowing until the end of the growing cycle. The variables analyzed in each collection were: number of leaves, leaf area, transverse and longitudinal diameter, root length, shoot, root and total dry matter. The obtained data were submitted to a joint analysis, and the measured variables were submitted to linear correlation with the significance based on the t test at 1 and 5% of probability, this analysis had the intention of evidencing the trend of linear association for the variables and analysis of canonical correlations. Radish plants with larger leaf area demonstrate lower root development, based on the coefficient of canonical correlation. There were positive correlations among all the analyzed variables, especially the leaf area with dry matter, plant height and leaf number.

The objective of this work was to identify the responsible mechanisms for the superior performance of soybean seeds produced under high phosphorus availability. Seed production of cultivars DM 66i68 RSF IPRO (more tolerant or more stable) and SYN 15630 IPRO (more sensitive or responsive) was carried out under doses proportional to 0, 50, 100, 150 and 200% of the recommended P for an expectation yield of 5 t ha-1 of grains. Phosphate fertilization promoted greater seedling growth, increased the yield components, the proportion between total shoot dry matter and grain production, in addition to increasing the concentration of minerals P, Ca, Mg, Fe and Zn. Seeds produced under greater availability of phosphorus present less loss of solutes during imbibition in the tests of electrical conductivity and potassium leaching and produce seedlings with higher rates of emergence speed, dry matter, and leaf area of seedlings.

O arroz é um dos alimentos mais produzido e consumindo pelo mundo e para isso se faz necessário que se tenha sementes de arroz de qualidade. Mediante a isto, esse trabalho tem como objetivo utilizar diferentes metodologias para superação de dormência em sementes de arroz da cultivar IRGA 424 RI, oriundos de diferentes agricultores do estado do Rio Grande do Sul. A metodologia emprega neste trabalho foi utilizar sementes nuas, sementes imersas em água, hipoclorito de sódio, pré-secagem para verificar o vigor desta semente através do teste de germinação e realizado o teste de tetrazólio para verificar a viabilidade das sementes, durante diferentes períodos de avaliação. Diante disso, pode verificar através dos resultados uma certa discrepância entre os diferentes períodos de avaliação e os diferentes processos empregados na superação de dormência, chegando à conclusão de que o hipoclorito de sódio e a imersão em água a 40°C não são bons para superar a dormência de arroz, mas em contrapartida as sementes nuas e o pré-resfriamento são métodos eficazes na superando de dormências de arroz como mostrou os resultados durante os diferentes tempos de avaliação.

Salinity and water deficit are among the main stress situations that affect germination and seedling development in the field. Thus, the objective was to evaluate the germination and growth of white oat seedlings subjected to water and saline stress at different temperatures. The experiment was carried out in a completely randomized design, in a triple factorial arrangement, with two osmotic solutions (PEG 6000 and NaCl), five osmotic potentials (-0.2, -0.4, -0.6 and -0.8 MPa) and two temperatures (20 and 25 °C), with four replications of 50 seeds each. Initially, the water content of the seeds was determined. In the treatment effects, germination, first germination count, shoot length, primary root and seedling fresh mass were evaluated. Osmotic potentials lower than -0.2 MPa reduce the germination and growth of white oat seedlings, regardless of the stressor agent and temperature. The simulations of the stress conditions harmed the germination and the initial growth of the seedlings by the decrease of the observed variables. The salt and water stress induced by sodium chloride solution was more drastic than that induced by polyethylene glycol 6000.

Os danos mecânicos na produção de sementes de soja acaba por se tornar um dos principais fatores limitantes no sistema de produção, sem contar o uso do hipoclorito é um produto químico muito nocivo à saúde humana. Diante disso, este trabalho tem como objetivo avaliar a inserção do uso da água em diferentes temperaturas e tempos de embebição nas sementes de soja das cultivares Zeus, Valente, Delta, TMG 7063 IPRO, com a finalidade de substituir o teste de hipoclorito por um teste mais rápido e sem a utilização do hipoclorito. O teste foi realizado no laboratório de Sementes na Universidade Federal de Pelotas, na qual foi utilizado 100 sementes, subdivididas em 4 repetições de 25 sementes das cultivares de soja e concentração de hipoclorito de sódio a 1% para a embebição da semente e contado o tempo com auxílio de um cronometro digital (2,4,6,8,10 minutos), diferentes temperaturas de água (20, 30, 40 e 50 °C).Pode observar e concluir que o teste com água quente foi mais efieciente os resultados quando submetidos hipoclorito de sódio a 1%, para ambas as cultivares de soja estudas.

Treatment of pumpkin seeds with silicon: effects on mineral nutrition of seedlings / Tratamento de sementes de abóbora com sílicio: efeitos na nutrição mineral das plântulas