Seleção de clones de figueira cv. roxo de Valinhos formados por gemas irradiadas

Abstract

RESUMO -A figueira (Ficus carica L.), pertencente à família das Moráceas, constitui-se numa das mais importantes frutíferas cultivadas, elevando o Brasil à condição de décimo maior produtor e exportador de figos do mundo. Porém, a ficicultura apresenta alguns problemas fitossanitários, além de, no Brasil, estar toda implantada com uma única cultivar, a Roxo de Valinhos, que produz frutos sem sementes, inviabilizando o melhoramento convencional. Nesse sentido, o melhoramento genético, com o uso de mutagênicos, passa a ser uma linha de pesquisa altamente importante, podendo contribuir enormemente para o desenvolvimento da cultura. Diante disto, o objetivo do presente trabalho foi selecionar mutantes em plantas de figueira formadas por estacas irradiadas com raios gama, a fim de aumentar sua variabilidade genética com relação ao desenvolvimento vegetativo e reprodutivo. Utilizaram-se plantas formadas por estacas originadas de gemas da cultivar Roxo de Valinhos irradiadas com raios gama, no irradiador tipo Gamma a 0,10 m do ápice, na dose de Gy com taxa de dose de 238 Gy/h. O experimento constou de 450 tratamentos, sendo cada planta formada considerada um tratamento, numerando-as sequencialmente de 1 a 450 e cultivadas em espaçamento de 2,5 x 1,5 m.. As avaliações foram realizadas a partir das características tanto das folhas quanto dos frutos, bem como da incidência das principais pragas e doenças da cultura nestas plantas. Da análise dos dados, conclui-se que há variabilidade genética entre os tratamentos e que algumas plantas são prováveis mutantes, mostrando-se assim com potencial para posteriores estudos, devendo ser testadas em plantios comerciais. Termos para indexação: Ficus carica, radiação gama, mutação. Gy with dose rate of 238 Gy/h. The experiment consisted of 450 treatments, where each formed plant was a treatment. The treatments were numbered sequentially from 1 to 450 and spaced 2.5 x 1.5 m. It was evaluated the vegetative and the fruits characteristics, and the incidence of major crop pests and diseases. The analysis data showed that there is genetic variability among treatments and that the plants under numbers 1, 5, 20, 79, 164, 189, 194, 201, 221, 214, 258, 301, 322, 392, 433 and 440 are probably genetic mutants that should be tested as commercial orchards. FIG CLONES SELECTION OF cv. ROXO DE VALINHOS OBTAINED BY IRRADIATED BUDS ABSTRACT -

Analysis of Global DNA Methylation in Irradiated Fig Selections

“…The experiment was conducted at the Epigenetics and Reproduction Laboratory of Medicine School of Ribeirão Preto (São Paulo, Brazil), using leaves of five selected irradiated plants based on their unique morphological characteristics [17]. The specimens consisted of cuttings irradiated with gamma rays, at the dose of 30 Gy, with 238 Gy•hour −1 dose rate, at the Energy Nuclear Center in Agriculture (Piracicaba, Brazil).…”

“…Low dose radiation can stimulate various biological processes and has been applied in different fields to produce mutant plants that can be used to improve crops [15]. From fig cuttings of the cultivar "Roxo-de-Valinhos" irradiated with gamma rays at a dose of 30 Gy [16], it was possible to select plants based on their unique and divergent morphological characteristics, and agronomic interest [17]. However, no polymorphisms were observed in irradiated figs subjected to molecular analysis, including random amplified polymorphic DNA (RAPD) and amplified fragment length polymorphism (AFLP) techniques, indicating that no genetic modifications had occurred.…”

Search for methylation-sensitive amplification polymorphisms in mutant figs

“…The specimens consisted of cuttings irradiated with gamma rays at the Energy Nuclear Center in Agriculture (Piracicaba, Brazil). Five irradiated plants considered to be mutants were used (Rodrigues et al, 2012a); these selections were compared to one another and to the cultivar 'Roxo-de-Valinhos', which served as a control.…”

“…Joyce and Cassells (2002) determined the cytosine methylation status of DNA in in vitro-developed microplants with various leaf morphologies by using AFLP marker analysis with methylation-sensitive restriction enzymes to test the hypothesis that DNA methylation could be used to characterize differences between treatments. While attempting to improve fig trees, Rodrigues et al (2012a) used cuttings of the cultivar 'Roxo-de-Valinhos' irradiated with gamma rays at a dose of 30 Gy to show that plants could be selected based on unique morphological characteristics that differed from those of controls. The selected characteristics included elongated fruit shape; elongated peduncle, which facilitates harvesting and increases the shelf life of fruits; large fruit size; and large fruit with a closed ostiole, which reduces the incidence of agricultural pest infestation and prevents fruit depreciation.…”

Cinética de secagem, contração volumétrica e análise da difusão líquida do figo (<italic>Ficus carica</italic> L.)

“…Dentre as 2000 espécies presentes no gênero Fícus, a Ficus carica é a única que tem valor econômico. Apresenta excelente adaptação a diferentes climas e é cultivada tanto em regiões subtropicais quentes como em climas temperados (Simão, 1971;Sousa, 2008;Rodrigues et al, 2012).…”