Duplicação cromossômica de gramíneas forrageiras: uma alternativa para programas de melhoramento genético

Pereira, Rafaela Corrêa; Davide, Lisete Chamma; Techio, Vânia Helena; Timbó, Ana Luiza Oliveira

doi:10.1590/s0103-84782012000700023

Cited by 26 publications

(25 citation statements)

References 25 publications

(52 reference statements)

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“…A espécie L. multiflorum se apresentou naturalmente na forma diploide, com 2n=2x=14 cromossomos (Pereira et al, 2012); no entanto, cultivares tetraploides, com 2n=4x=28 cromossomos, foram originados pelo melhoramento genético vegetal, através da técnica de duplicação cromossômica (Oliveira, 2013).…”

Section: Contagem Cromossômicaunclassified

Caracterização Morfoanatômica, Contagem Cromossômica E Viabilidade Polínica De Biótipos De Azevém Suscetível E Resistentes Ao Herbicida Glyphosate

et al. 2015

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RESUMO -O azevém é uma planta daninha de ciclo anual, encontrada em praticamente todas as lavouras de inverno, em pomares e vinhedos da região Sul do Brasil. A espécie é normalmente controlada pelo herbicida glyphosate, no entanto, o uso continuado desse produto selecionou biótipos resistentes. Diferenças na suscetibilidade do azevém a herbicidas têm sido atribuídas a características morfológicas, anatômicas e genéticas das plantas. Os objetivos deste trabalho foram realizar a caracterização morfoanatômica, adequar metodologia para a análise citológica de cromossomos e indicar corantes para testes de viabilidade polínica de biótipos de azevém suscetível e resistentes ao herbicida glyphosate. As sementes dos biótipos de azevém suspeitos de resistência provieram do município de São Valentin, RS (SVA 1 e SVA 4), e Passo Fundo, RS (PFU 5), e as do biótipo conhecidamente suscetível (SVA 2), de São Valentin. Os biótipos de azevém estudados que apresentam resistência ao herbicida glyphosate não podem ser diferenciados do biótipo suscetível através de aspectos morfológicos, não existindo diferenças anatômicas de folha e raiz que evidenciem possibilidade da absorção diferencial do herbicida glyphosate entre os biótipos de azevém. A metodologia para a análise citológica dos biótipos de azevém merece adequações para melhor nitidez dos cromossomos, podendo-se aumentar o tempo de hidrólise e de exposição ao agente antimitótico utilizado neste trabalho, bem como testar outros agentes. Todos os corantes apresentaram bom desempenho na determinação da viabilidade polínica frente aos biótipos avaliados, exceto o azul de tripan, que subestimou os resultados.Palavras-chave: anatomia, cromossomos, Lolium multiflorum, morfologia, Poaceae. ABSTRACT -Ryegrass is an annual weed found in all winter

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Section: Contagem Cromossômicaunclassified

Caracterização Morfoanatômica, Contagem Cromossômica E Viabilidade Polínica De Biótipos De Azevém Suscetível E Resistentes Ao Herbicida Glyphosate

et al. 2015

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“…(Poaceae) arouse great interest among farmers because of their high dry matter production, as well as adaptability, persistence, ease of establishment, and a good nutritional value; these forages also have reduced disposition to disease and present good growth during the entire year, not only during the rainy season (Costa et al, 2006 (Pereira et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

Death of pastures syndrome: tissue changes in Urochloa hybrida cv. Mulato II and Urochloa brizantha cv. Marandu

2017

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The quality of forage production is a prerequisite to raising livestock. Therefore, income losses in this activity, primarily cattle raising, can result in the impossibility of economic activity. Through the qualitative and quantitative anatomical study of Urochloa hybrida cv. Mulato II and U. brizantha cv. Marandu, we searched for descriptions and compared changes in the individual vegetative body from populations with death syndrome pastures (DPS). Specimens were collected at different physiological stages from farms in northern Mato Grosso. After collection, the individuals were fixed in FAA 50 and stored in 70% alcohol. Histological slides were prepared from the middle third of the sections of roots, rhizomes, and leaves, and the proportions and characteristics of tissues were evaluated in healthy, intermediate, and advanced stages of DPS. Changes were compared between cultivars. With the advancement of the syndrome, the following changes were observed: a more marked decrease in the length of roots in U. hybrida; disorganization of the cortical region of the roots and rhizome cultivars; fungal hyphae in roots and aerenchyma formation in U. hybrida; a decrease in sclerenchyma fiber proportions in roots and leaves; sclerification of the epidermis of U. brizantha rhizomes; and an increase in pericyclic fibers in U. hybrida. Furthermore, there was a decrease in the volume of epidermal cells of the abaxial face of the leaves of both cultivars, with a greater reduction in U. hybrida; a gradual decrease in thickness in the midrib of leaves similar to leaf mesophyll; conduction system obstructions; partial or total cell lysis in roots and rhizomes affected by the syndrome. Obstructions in sieve tube element and companion cells, and sometimes obstruction in xylem vessel elements. The evolution of DPS in cultivars was similar, but there were variations, arising probably from the physiological response to stress, such as aerenchyma formation in the root and increased pericycle in the rhizome of U. hybrida.Keywords: forage, plant anatomy, fungal hyphae. Síndrome da morte das pastagens: Alterações teciduais em Urochloa hybrida cv. Mulato II e Urochloa brizantha cv. Marandu ResumoA produção de forragem de qualidade é um pressuposto indispensável à atividade pecuária moderna. Dessa forma, perdas de rendimento nesta atividade preliminar à criação bovina, podem inviabilizar esta atividade econômica. Através de estudos anatômicos qualitativos e quantitativos em Urochloa hybrida cv. Mulato II e U. brizantha cv. Marandu buscou-se descrever e comparar as alterações do corpo vegetativo de indivíduos de populações que apresentam síndrome da morte das pastagens (SMP). Foram coletados indivíduos em estádios morfológicos distintos em propriedades rurais no norte de Mato Grosso, Amazônia Meridional. Após a coleta, os indivíduos foram fixados em FAA 50 e armazenados em álcool 70%. Lâminas histológicas foram confeccionadas a partir de secções do terço médio de raízes, rizomas e folhas, onde foram avaliadas as características e p...

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“…Antimitotic substances, such as colchicine, which is an alkaloid that is widely used in forage species, are used in the induction of polyploidy (Pereira et al, 2012). Several duplication studies have been conducted on Brachiaria, including on seeds germinated in vivo (Swenne et al, 1981;Timbó et al, 2014) and the in vitro culture of germinated seeds, multiple shoots (Ishigaki et al, 2009), and basal segments (Pinheiro et al, 2000;Simioni and Valle, 2009).…”

Section: Introductionmentioning

confidence: 99%

“…Several duplication studies have been conducted on Brachiaria, including on seeds germinated in vivo (Swenne et al, 1981;Timbó et al, 2014) and the in vitro culture of germinated seeds, multiple shoots (Ishigaki et al, 2009), and basal segments (Pinheiro et al, 2000;Simioni and Valle, 2009). In general, successfully obtaining polyploids depends on several exogenous factors (Pereira et al, 2012), and the use of colchicine causes side effects such as sterility, abnormal growth, chromosomal loss or rearrangement, mutations (Luckett, 1989), and mixoploidy (Pereira et al, 2012). These aspects should be evaluated when analyzing the degree of plant stability.…”

Section: Introductionmentioning

confidence: 99%

Microsporogenesis analysis validates the use of artificially tetraploidized Brachiaria ruziziensis in breeding programs

et al. 2016

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ABSTRACT. The genus Brachiaria contains species that have great economic importance in the Brazilian agricultural sector, as they enable cattle ranching on acid and poor soils with species that are resistant to spittlebugs and form crop-livestock-forest integration systems. The genus mainly consists of tetraploid (2n = 4x = 36) and apomictic species such as B. decumbens and B. brizantha. Sexuality is found in diploid species (2n = 2x = 18) such as B. ruziziensis. Interspecific hybridization between species of interest is possible by the artificial tetraploidization of B. ruziziensis and the subsequent hybridization with genotypes of B. brizantha and B. decumbens. Therefore, tetraploidized plants have to have normal meiosis or low rates of irregularities, as well as produce viable pollen grains. The objective of this study was to compare meiosis and pollen grain viability and morphology in artificially tetraploidized B. ruziziensis with that of descendants generated from crossing and selfing. The frequency of meiotic abnormalities ranged from 4.43 to 11%, and pollen viability ranged from 61 to 85%. Abnormalities were detected from prophase I to the tetrad stage with a variable frequency between the genotypes. The meiotic behavior of the artificially tetraploidized plants was little affected, and the pollen viability of the genotypes was high. Regarding pollen grain ultrastructure, there were no variations or morphological changes in the different genotypes. The genotypes have meiotic stability and high pollen viability, and can be incorporated into Brachiaria breeding programs.

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Duplicação cromossômica de gramíneas forrageiras: uma alternativa para programas de melhoramento genético

Cited by 26 publications

References 25 publications

Caracterização Morfoanatômica, Contagem Cromossômica E Viabilidade Polínica De Biótipos De Azevém Suscetível E Resistentes Ao Herbicida Glyphosate

Caracterização Morfoanatômica, Contagem Cromossômica E Viabilidade Polínica De Biótipos De Azevém Suscetível E Resistentes Ao Herbicida Glyphosate

Death of pastures syndrome: tissue changes in Urochloa hybrida cv. Mulato II and Urochloa brizantha cv. Marandu

Microsporogenesis analysis validates the use of artificially tetraploidized Brachiaria ruziziensis in breeding programs

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