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URI permanente desta comunidadehttps://thoth.dti.ufv.br/handle/123456789/3352
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Item Water stress in germination, growth and development of coffee cultivars(Associação Brasileira de Tecnologia de Sementes - ABRATES, 2018) Almeida, Julieta Andréa Silva de; Azevedo, Mary Túlia Vargas Lobato Guedes de; Salomon, Marcus Vinicius; Medina, Priscila FratinThe aim of this study was to evaluate the effect of water stress on the germination of Coffea arabica seeds and the growth and development of plants from these seeds. Seeds of the cultivars Bourbon Vermelho, Mundo Novo, and BA-10 were placed to germinate in the dark at 30 ºC in the presence and absence of 100 g/L of polyethylene glycol 6000. The water stress applied delayed the beginning of seed germination by seven days in relation to seeds of the control, which had achieved responses of up to 50%, but there were no differences between the treatments at the end of the experiment. Furthermore, the length of the primary root in seeds germinated under water stress was less than in the control treatment, especially for the cultivar Mundo Novo. Plants of the cultivars Bourbon Vermelho and Mundo Novo developed from seeds previously germinated under water stress exhibited reduced height and fewer leaf pairs than those from the control, whereas ‘BA-10’ responded in a similar way in both treatments. Thus, the cultivars Bourbon Vermelho and Mundo Novo were more sensitive to the water stress applied in the germination phase than ‘BA-10’.Item Effect of temperature and cytokinin on the capacity of direct somatic embryogenesis in Coffea arabica L. genotypes(Editora UFLA, 2014-07) Almeida, Julieta Andréa Silva de; Leal, Rebeca Rocha; Carmazini, Valéria Cristina Barbosa; Salomon, Marcus Vinicius; Guerreiro-Filho, OliveiroThe vegetative multiplication of Coffea arabica hybrids can be carried out by direct somatic embryogenesis. The objective of this study was to verify if temperature and cytokinins could influence the capacity for direct somatic embryogeneis in arabica genotypes. For this purpose foliar explants taken from adult plants of three C. arabica genotypes, hybrids 812 and 956 and cultivar Catuaí, were inoculated into a culture medium with 1⁄2 MS salts, 20.0 g l -1 sucrose and 30 μM 6-benzyladenine (6-BA) or 10 μM 2-isopenteniladenina (2-iP) and submitted to temperatures of 25 and 30 oC in the absence of light. The treatments were evaluated with respect to the number of somatic embryos formed per foliar explant, at 270 days after the beginning of the experiment. A completely random experimental design was adopted with a 3 x 2 x 2 (genotype x temperature x plant growth regulator) factorial scheme, with ten replications per treatment and two explants in each. Temperature of 30 o C favored significantly the formation of somatic embryos when compared to 25 o C and this response pattern predominated amongst the three genotypes. On the other hand, 6-BA and 2-iso-pentenladenine caused similar answers for the majority of genotypes. The results of this study showed that temperature has a significant influence on the direct somatic embryogenesis capacity of C. arabica genotypes.