Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1992. / Vita. Abstract. Includes bibliographical references (leaves 36-37). Also available via the Internet.

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No. of bitstreams: 1 Dissertação - Rody França Nogueira Lobato.pdf: 1239580 bytes, checksum: 550fdf62d9efe7570bc695ce5a048a11 (MD5) Previous issue date: 2016-04-01 / CNPq - Conselho Nacional de Desenvolvimento Científico e Tecnológico / Embrapa developedin 2010 the first commercial hybrid between caiaué specie (Elaeis oleifera) and oil palm (E. guineensis) (HIE OxG) in Brazil, called BRS Manicoré, as an alternative to palm oil production in incidence areas of the anomaly lethal yellowing. For Elaeisgenre, although there is an established protocol on a commercial scale, the seeds need procedures to overcome dormancy, obtaining sprouted seedsofgood quality, that is essential for establishing a stand. The study aimed to evaluate: I. Exposure time and effect of hydrogen cyanamide (CH) on seed germination of HIE OxG; II. Effective concentration of CH and germination percentage; III. Effect of germination speed in the development of seedlings in the nursery pre-stage. The experiments were carried out at Embrapa Western Amazon, using seeds of commercial lots, freshly harvested and processed.The water content of the seed was adjusted to 15-16% and 20-21%. For all experiments,the design was randomized blocks with 500 seeds. Experiment 1. Comprised of five treatments and four replications, with immersion in CH solution in the concentrations of 2.0 and 2.5% for 24 and 48 hours and thermal treatment (TT) (at 39 ° C ± 1 for 75 daysand humidity air around 70%); Experiment 2. It wereevaluated six treatments and four replications, with soaking seeds in CH solution for 24 hours at concentrations of 0.5, 1.0, 1.5 and 2.0% of the commercial product; soaking in water and TT. Experiment 3. Four treatments (screening / rating) at 7, 14, 21 and 28 days after germination room entry in five replicates of eight seedlings. After treatment, seeds were immersed in water for nine days and then keptin a growth room (25 ° C to 27 ° C). Smaller percentages of germinated seeds (PSG) were obtained with immersion on CH for 48hours. PSG seeds soaked in water was less than the values obtained in the treatments with CH and TT. The plantlets from the first and second screening showed greater stem diameter. Thegreatest heights of the seedlings were obtained from the seeds of the second and third screening. Loweraverage fresh matter of shoot first and fourth screening and fresh weight of root were found in the seeds of the first, third and fourth screening. It is concluded that hydrogen cyanamide has a positive effect on the germination of seeds of BRS Manicoré, however, its use is not recommended to replace the TT by the lowest percentage of germinated seeds. For the experiment where seedling vigor were evaluated in pre-nursery, the results showed a trend toward greater vigor to seedlings from seeds of the second (14 days) and third screening (21 days) / A Embrapa lançou em 2010 o primeiro híbrido comercial entre as espécies caiaué (Elaeis oleifera) e dendê (E. guineensis) (HIE OxG) desenvolvido no Brasil, denominado BRS Manicoré, como alternativa para produção de óleo de dendêem áreas de incidência da anomalia amarelecimento fatal, letal para o dendê. Para o gênero Elaeis, embora, exista um protocolo estabelecido, em escala comercial, as sementes necessitam de procedimentos para superação da dormência, obtendo-se sementes germinadas, de boa qualidade, fundamental para estabelecimento de um estande.O estudoobjetivou avaliar: I. Tempode exposiçãoe efeito da cianamida hidrogenada (CH) na germinação de sementes do HIE OxG; II. Concentração efetiva de CH e percentual germinativo; III. Efeitoda velocidade de germinação nodesenvolvimento de plântulas na fase de pré-viveiro.Os experimentos foram realizados naEmbrapa Amazônia Ocidental,utilizando sementes de matrizes comerciais, recém-colhidase beneficiadas. O teor de água das sementes foiajustadopara 15 a 16% e 20a 21%. Para todos os experimentos o delineamento foi em blocos casualizados com 500 sementes. Experimento 1.Constituído de cinco tratamentos e quatro repetições, com imersão em solução de CHnas concentrações de 2,0 e 2,5% por 24 e 48 horas e Tratamento térmico (TT)(à 39 ºC ± 1 por 60 dias eumidade do ar em torno de 70%); 2. Avaliaram-seseis tratamentos e quatrorepetições, com imersão das sementes em solução de CHpor 24h nas concentrações de 0,5, 1,0, 1,5 e 2,0% do produto comercial; embebição em agua e TT. Experimento 3. Quatrotratamentos (triagens/avaliações) aos 7, 14, 21 e 28 dias após entrada na sala de germinaçãoe cinco repetições de oito plântulas. Após serem submetidas aos tratamentos,as sementes foram imersas em água por nove dias, posteriormente mantidas em sala de germinação (25 °C a 27 °C). As menores porcentagens de sementes germinadas (PSG) foram obtidas com imersão em CH por48 horas. APSGdassementes embebidas em águafoi inferior aos valores obtidos nos tratamentos com CHe TT.As plântulas oriundas da primeira e segunda triagem apresentaram um diâmetro maior do coleto. As maiores alturas das plântulas foram obtidas com as sementes da segunda e terceira triagem. Conclui-se quea cianamida hidrogenada tem efeito positivo sobre a germinação de sementes do BRS Manicoré, porém,o seu uso não é recomendado em substituição ao TT pelo menor percentual de sementes germinadas.Para o experimento onde foram avaliados vigor de plântulas em pré-viveiro, os resultados mostraram uma tendência de maior vigor para mudas oriundas de sementes da segunda (14 dias) e terceira triagem (21 dias).

Temperate deciduous fruit trees have poor and delayed bud break when they are grown in warm areas. The delay is due to a lack of the chilling which is required to break bud endodormancy. Bud endodormancy can be overcome in some species by treatments such as H₂CN₂, heat, and bud scale removal. We tested the effects of chilling, H₂CN₂, heat, and removing scales on bud break of floral and vegetative buds of 'Tifblue' rabbiteye blueberry (Vaccinium ashei Reade). Hydrogen cyanamide was effective in promoting floral bud break of 'Tifblue' only on whole plants, at chilling exposures between 300 to 500 hours. However, vegetative bud break was increased by H₂CN₂ at a wider range of ~hilling exposures than floral buds in both whole plants and cut shoots. Optimum vegetative bud break was induced by H₂CN₂ at 125 and 250 mM for whole plants and cut shoots, respectively. Hydrogen cyanamide was highly phytotoxic to floral buds compared to vegetative buds. However, floral buds of whole plants became tolerant to H₂CN₂ as chilling increased. Injury to vegetative buds was significant only at 500 mM H₂CN₂. The chilling requirement for 'Tifblue' floral buds of whole plants was 500 hours. In contrast, vegetative buds did not have a significant relationship with chilling exposure in either cut shoots or whole plants. Heat treatment was effective in promoting floral bud break of cut shoots only at 190 chilling hours at 30 minutes heat exposure. Heat (47°C) for I hr was effective in promoting vegetative bud break, but the effectiveness varied with chilling level and depended on time of heat exposure. Bud scale removal did not promote floral bud break, but increased vegetative bud break, although not significant compared to control. Finally, we discovered that vegetative buds remained dormant even after they had received more than adequate chilling. However, both H₂CN₂ treatment and floral bud removal resulted in increased vegetative bud break, although the effect of H₂CN₂ was less than floral bud removal. This suggests that vegetative buds were inhibited by floral buds and that H₂CN₂ could partially overcome this paradormant effect. / Master of Science