Produ??o e qualidade fisiol?gica de sementes de crambe (Crambe abyssinica Hochst) em resposta a aduba??o pot?ssica e diferentes ?pocas de colheita

• Autor(a) principal: Silva, Ludmila Fonseca da
• Data de Publicação: 2016
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UFRRJ
• Texto Completo: https://tede.ufrrj.br/jspui/handle/jspui/1848
• topic: production; quality; Crambe abyssinica; produ??o; qualidade; Agronomia

Crambe (Crambe abyssinica Hochst) is a fall/winter crop in Brazil, short-cycle, drought-tolerant and low temperatures tolerant, recycling of nutrients, crop rotation participant and their seeds have high oil content. Thus, crambe is presented as an alternative to biodiesel production and allows the inclusion of small and medium producers in its production. Studies have shown the positive effect of potassium fertilization on crambe seed productivity, and the importance of determining the proper harvest time, to ensure maximum seed quality, avoid productivity losses and possible infections. The objective was to evaluate the yield and physiological quality of crambe seeds in response to potassium fertilization and different harvest times. An experiment under field conditions was installed in 2013 and this was repeated in 2014, using a split plot design, potassium fertilization as main plots (0, 15, 30, 60 and 90 kg K2O ha-1) and three harvest times as subplots. At each harvest, there were evaluated the seed production, production components for crambe plant, seed yield and plant morphological characteristics. In the laboratory, the seeds produced were submitted to evaluations of germination and vigor (first count, electrical conductivity and accelerated aging), a month after harvest and after six months of storage in a dry chamber (18?C and 45% RH). By the results it was concluded that in 2013, potassium fertilization and harvest time did not favored the dry matter of aerial part, the number of branches per plant, the number of seeds per plant, the mass of 100 seeds and the seed yield. In 2014, the plants fertilized with 90 kg K2O ha-1 in the first and second harvest time, 88 and 95 days after sowing (DAS) showed a higher seed number and yield per plant, as well as higher weight of 100 seeds. The contribution of seed production in the main stem was higher when the crop was harvested after 85 DAS in 2013 and, at 88 and 95 DAS in 2014 obtained with the dose of 90 kg K2O ha-1 . Seeds harvested in the third time, when evaluated after harvest (initial evaluation), had lower germination without treatment to overcome dormancy, regardless of potassium fertilization, in both years of cultivation, indicating that the seeds had reached physiological maturity and the mechanisms to overcome dormancy were already present. After six months of storage, crambe seed harvested in the third time had higher germination, without treatment to overcome dormancy, regardless of potassium fertilization in both crops.