Qualidade fisiológica e sanitária, dormência e atividade enzimática de sementes de cultivares de arroz armazenadas em diferentes ambientes

• Ano de defesa: 2012
• Autor(a) principal: Marques, Elizabeth Rosemeire
• Orientador(a): Araújo, Eduardo Fontes
• Banca de defesa: Guimarães, Valéria Monteze , Donzeles, Sergio Mauricio Lopes , Silva, Roberto Ferreira da
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Doutorado em Fitotecnia
• Departamento: Plantas daninhas, Alelopatia, Herbicidas e Resíduos; Fisiologia de culturas; Manejo pós-colheita de
• País: BR
• Palavras-chave em Português: Sementes; Oryza sativa L.; Conservação
• Palavras-chave em Inglês: Seeds; Oryza sativa L.; Conservation
• Área do conhecimento CNPq: CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::FITOTECNIA
• Link de acesso: http://locus.ufv.br/handle/123456789/1178

Rice (Oryza sativa L.) is one of the most cereals produced and consumed in the world and its seed, fundamental input to produce a crop, can have the quality affected by storage conditions. The objective of this study was to evaluate dormancy, physiological quality, health and enzymatic activity of seeds of rice cultivars during storage in different environments. The experiments were conducted in the Seed Analysis Laboratory of the Crop Science Departament and in the Laboratory of Enzymology, Protein and Peptides (BIOAGRO) in the Federal University of Viçosa - UFV. Seeds were produced by the Agricultural Research Company in Minas Gerais (EPAMIG), in Lambari-MG. After harvesting, the seeds of five rice cultivars (BRSMG Seleta, BRS Ourominas, BRSMG Curinga, BRSMG Relâmpago and BRSMG Caravera) were dried in the sun, to reach moisture content at around 13%. Then, they were packed in paper and stored in four environments: 5 ± 2 °C / 70 ± 5 % RH, 12 ± 2 °C / 70 ± 5 % RH, 18 ± 2 °C / 65 ± 5 % RH and in uncontrolled condition of temperature and relative humidity (laboratory). Physiological quality, health and enzymatic activity were evaluated at the beginning and at 3, 6, 9 and 12 months of storage. Physiological quality was evaluated by germination test, first germination counting, electrical conductivity, accelerated aging, sand emergence and emergence velocity index. The activities of catalase, ascorbate peroxidase and α-amilase, only in seeds Ourominas and Caravera cultivars were determined. The experiment was conducted in split split plots in a completely randomized design with three replications. Environmental factor was applied in the plots, cultivars in the subplots and storage time in subsubplots. The dormancy of seeds stored in the laboratory environment was exceeded in a shorter time than the dormancy of seeds stored in cold. Only seeds from Seleta and Ourominas cultivars, regardless the environment, maintained germination above the minimum required for commercialization until six months of storage. Seeds stored in the laboratory environment showed low physiological quality. The main fungi detected in seeds of rice in the different environments were: Fusarium spp., Bipolaris sp., Phoma sp. and Gerlachia sp., and storage fungi Aspergillus spp. and Penicillium sp. Storage fungi appeared in 3 months and increased during storage period. Catalase and ascorbate peroxidase activity increased during storage period and α-amilase activity were higher in the beginning and at 3 months of storage. Enzymes catalase and ascorbate peroxidase can be used as an indicator of physiological quality of rice seeds.