Federal University of Roraima

About: Federal University of Roraima is a based out in . It is known for research contribution in the topics: Population & Thermogravimetry. The organization has 981 authors who have published 1218 publications receiving 7849 citations. The organization is also known as: Federal University of Roraima.

Initial Growth of Seedlings of Diferent Pineapple Cultivars in Boa Vista, RR

Abstract: Atualmente, no Brasil, o cultivo do abacaxizeiro, em escala comercial, e quase que exclusivamente com as cultivares Smooth Cayenne e Perola, no entanto, ambas sao suscetiveis a fusariose. A insercao de novas cultivares, com aceitacao no mercado de exportacao e resistente a fusariose e imprescindivel para o sucesso da cultura. O objetivo deste estudo foi avaliar o desenvolvimento vegetativo precoce de cinco cultivares de abacaxi derivadas de micropropagacao (BRS Ajuba, BRS Imperial, IAC Fantastico, Perola e BRS Vitoria). As mudas foram produzidas e aclimatizadas no Laboratorio de Biotecnologia Biomudas, localizado em Venda Nova do Imigrante – ES, sendo posteriormente transportadas para Boa Vista, RR para implantacao do experimento, onde foram conduzidas a casa de vegetacao, sob condicoes climaticas controladas. Utilizou-se o delineamento inteiramente casualizado, em esquema de parcelas subdivididas, sendo cinco cultivares de abacaxizeiro (BRS Ajuba, IAC Fantastico, BRS Imperial, Perola e BRS Vitoria), oriundas de micropropagacao, aleatorizadas nas parcelas e cinco epocas de avaliacao (30, 60, 90, 120 e 150 dias apos o transplantio - DAT) nas subparcelas, com quinze repeticoes. As variaveis de desenvolvimento vegetativo avaliadas foram: altura da planta, diâmetro da roseta, numero de folhas, comprimento e largura de folha ”D”, alem da percentagem de sobrevivencia, ao final do experimento. As cultivares IAC Fantastico e Perola apresentaram maior desenvolvimento vegetativo em relacao a BRS Ajuba, BRS Imperial e BRS Vitoria. As cultivares IAC Fantastico e Perola, em razao da maior precocidade, podem ser transplantadas para local definitivo a partir de 30 DAT das mudas em casa de vegetacao, as demais cultivares requerem 150 DAT. Palavras-chave: Aclimatacao de Plantas. Crescimento de Mudas. Cultivo in vitro. Fruticultura. Micropropagacao de Plantas. Abstract Currently, the commercial pineapple cultivation in Brazil relies almost exclusively on the cultivars Smooth Cayenne and Perola. However, both are susceptible to fusariosis. Develment of new cultivars, that are both acceptable to the export market and resistant to fusariosis, is essential for the continued crop success. The objective of this study was to evaluate early vegetative development of five micropropagation-derived pineapple cultivars (BRS Ajuba, BRS Imperial, IAC Fantastico, Perola and BRS Vitoria). Seedlings were produced and acclimatized at the Biomudas Biotechnology Laboratory, Venda Nova do Imigrante, Espirito Santo, Brazil, and were then transported to Boa Vista, Roraima, for the experiments. Here they were placed in a greenhouse under controlled climatic conditions and a completely randomized design implemented, using a subdivided plots scheme, with the micro-porpergation generated seedlings. Location randomized within plots, and evaluation running for five different periods (30, 60, 90, 120 and 150 days after transplant - DAT) in the subplots, with fifteen replicates. Evaluated vegetative development variables weere: plant height, rosette diameter, number of leaves, "D" leaf length and width, as well as percentage survival at experiment end. Cultivars IAC Fantastico and Perola showed greater vegetative development than BRS Ajuba, BRS Imperial and BRS Vitoria. The cultivars IAC Fantastico and Perola, due to their greater precocity, can be transplanted to a final growth location 30 days after seedling transplantion into a greenhouse, while other cultivars require 150 DAT occur. Keywords: Plants Acclimation . Seedlings Growth. In vitro Cultivation. Fruit Growing. Pineapple Micropropagation .

Callus induction and pro-embryogenic mass formation in Myrciaria dubia , an important medicinal and nutritional plant

Abstract: Cacari is a fruit tree that is native to the Amazon region of Brazil. The fruit is considered to have the highest vitamin C content of any edible fruit (13.757 mg 100 g-1 dry weight). The objective of this study was to evaluate the effects of 2,4-D and 6-BAP alone or in combination on in vitro callus induction and pro-embryogenic mass formation in cacari stem segments in different culture media as a precursor for cacari micropropagation. The experiment consisted of two culture media (MS and WPM) and combinations of four concentrations of 2,4-D (0, 1, 2 and 4 mg L-1) and BAP (0, 0.25, 0.5 and 1 mg L-1). The results showed that the highest percentage of callus formation (99%) was obtained in WPM supplemented with 4 mg L-1, 2,4-D and 1 mg L-1 BAP, and this combination resulted in 93% pro-embryogenic mass formation.

Doses e modos de aplicação de ureia revestida com polímero no cultivo de alface americana

Abstract: O objetivo deste estudo foi avaliar o efeito de doses e modos de aplicacao de N, fornecido por meio de ureia revestida, no estado nutricional e producao de alface americana. Utilizou-se o delineamento em blocos ao acaso em arranjo fatorial 6x4 + 1, sendo seis doses de N (28,75; 57,50; 115,00; 172,50; 230,00; 287,50 kg ha-1 de N), como fonte a ureia revestida, e quatro modos de aplicacao do nutriente (100% da dose no transplante; 50% no transplante + 50% aos 10 dias apos o transplante (DAT); 25% no transplante + 75% aos 10 dias DAT; 25% no transplante + 25% a cada cobertura, aos 10, 20 e 30 DAT). No tratamento adicional utilizou-se a ureia convencional. Foram determinados os teores foliares de N, P, K, Ca e Mg, a massa fresca total e comercial da cabeca, o diâmetro do caule, a altura da planta e o diâmetro da cabeca aos 30 e 60 dias apos o transplante. Verificou-se que a adubacao nitrogenada aumentou os teores foliares de N, Ca e Mg, e reduziu os teores foliares de K e P. Nao houve influencia das doses de N proveniente de ureia revestida com polimero e dos modos de aplicacao nos atributos morfologicos e produtivos da cultura. Palavras-chave: Lactuca sativa L.; nitrogenio; fertilizante de liberacao lenta; fertilizante de liberacao controlada. RATES AND APPLICATIONS WAYS OF POLYMER-COATED UREA IN CRISPHEAD LETTUCE CULTIVATION ABSTRACT: The aim of this study was to evaluate the effect of N rates (using a polymer-coated urea) and N application ways in nutritional status and yield of crisphead lettuce. The randomized block design in a 6 x 4 + 1 factorial arrangement was used, with six N rates (28.75, 57.50, 115.00, 172.50, 230.00, 287.50 kg ha-1 of N), with the use of polymer-coated urea, and four nutrient application ways (100% of the transplant rate, 50% at the transplant + 50% at the 10 days after the transplant (DAT), 25% at the transplant + 75% at 10 days DAT, 25% at transplant + 25% at each side dressing fertilization at 10, 20 and 30 DAT). The additional treatment was related to the recommended N fertilization using conventional urea. N, P, K, Ca and Mg, total and commercial yield, stem diameter, plant height and head diameter were determined at 30 and 60 days after transplant. Nitrogen fertilization increased the N, Ca and Mg foliar levels, independently of the application way. However, in general, it reduced the leaf levels of K and P. There was no influence of N rates from polymer-coated urea and application way on the morphological attributes and yield of the crop. Keywords: Lactuca sativa L.; nitrogen; slow-release fertilizer; controlled-release fertilizer.

Container volume and controlled-release fertilizer influence the seedling quality of Agonandra brasiliensis

Abstract: Agonandra brasiliensis e uma arvore de florestas tropicais, com ampla ocorrencia na regiao do Cerrrado brasileiro. Apesar do seu potencial como madeira e para reflorestamento, eficientes protocolos para a producao de mudas ainda estao em falta. Objetivouse avaliar caracteristicas morfologicas para a qualidade de mudas de A. brasiliensis, em condicoes de viveiro, em funcao do volume do recipiente e dose de fertilizante de liberacao controlada. O experimento foi realizado em esquema fatorial 2 x 5, testando-se dois volumes (1,8 L e 2,2 L) de recipiente e cinco doses (0 g L-1, 1 g L-1, 2 g L-1, 4 g L-1 e 8 g L-1) do fertilizante encapsulado Forth Cote® (formulacao NPK 15-09-12). As parcelas constituiram-se de cinco mudas homogeneas transplantadas em sacos de polietileno (15 cm x 35 cm) com substrato de areia media lavada. As seguintes caracteristicas foram mensuradas: comprimento da parte aerea; diâmetro do caule; incrementos em comprimento e diâmetro; materia seca total; materia seca da parte aerea e da raiz e a razao entre elas. Tambem foi determinado o Indice de Qualidade de Dickson. A qualidade das mudas para caracteres morfologicos como comprimento da parte aerea, diâmetro de caule e materia seca total foi especialmente favorecida por tratamentos que combinaram o fertilizante de liberacao controlada em dose aproximada de 5,0 g L-1 e recipiente com volume de 2,2 L.