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1.
Sci. agric ; 77(3): e20180233, 2020. tab, ilus
Artigo em Inglês | VETINDEX | ID: biblio-1497854

Resumo

The aim of this study was to investigate the effect of heat stress on 12 bean genotypes through the analysis of their reproductive biology in terms of flowering, pollen viability, meiotic behavior, and production. Plants were grown in a climate chamber at 25-20 °C (day and night) and at a high temperature treatment 37-26 °C (day and night) from the vegetative (V4) development stage to physiological maturity. The experimental design was 2 × 12 factorial arrangement with six replications and the factors consisted of heat treatments and genotypes. In three replications, the number of newly opened flowers was checked daily. At physiological maturity, the following traits were evaluated: percentage of pod set, number of pods, number of viable seeds, number of aborted seeds, 100 seed weight, and seed yield (g per plant). The other three replications were used to collect flowers to create slides to study viability of the pollen grain and analyze the meiotic behavior. The heat treatment factor significantly affected the following traits: total number of pollen grains, number of flowers, number of pods, pod set, number of viable seeds, 100 seed weight, and seed yield. The raised temperature reduced these variables, except for percentage of pod set, and increased meiotic irregularities. The mean values regarding seed yield were 16.39 g per plant for the control treatment and 7.46 g per plant under high temperature. IAC Imperador, FT Nobre, Pérola, BRS Estilo, and IAC Diplomata stood out for higher bean seed yield under increased temperature.


Assuntos
Phaseolus , Pólen , Polinização
2.
Sci. agric. ; 77(3): e20180233, 2020. tab, ilus
Artigo em Inglês | VETINDEX | ID: vti-25046

Resumo

The aim of this study was to investigate the effect of heat stress on 12 bean genotypes through the analysis of their reproductive biology in terms of flowering, pollen viability, meiotic behavior, and production. Plants were grown in a climate chamber at 25-20 °C (day and night) and at a high temperature treatment 37-26 °C (day and night) from the vegetative (V4) development stage to physiological maturity. The experimental design was 2 × 12 factorial arrangement with six replications and the factors consisted of heat treatments and genotypes. In three replications, the number of newly opened flowers was checked daily. At physiological maturity, the following traits were evaluated: percentage of pod set, number of pods, number of viable seeds, number of aborted seeds, 100 seed weight, and seed yield (g per plant). The other three replications were used to collect flowers to create slides to study viability of the pollen grain and analyze the meiotic behavior. The heat treatment factor significantly affected the following traits: total number of pollen grains, number of flowers, number of pods, pod set, number of viable seeds, 100 seed weight, and seed yield. The raised temperature reduced these variables, except for percentage of pod set, and increased meiotic irregularities. The mean values regarding seed yield were 16.39 g per plant for the control treatment and 7.46 g per plant under high temperature. IAC Imperador, FT Nobre, Pérola, BRS Estilo, and IAC Diplomata stood out for higher bean seed yield under increased temperature.(AU)


Assuntos
Phaseolus , Pólen , Polinização
3.
Sci. agric ; 74(5): 371-377, Sept.-Oct. 2017. ilus, tab
Artigo em Inglês | VETINDEX | ID: biblio-1497664

Resumo

ABSTRACT: Seedlessness in fruit is a trait that is much sought after by juice making industries. Close to the city of São Sebastião do Caí, in the state of Rio Grande do Sul (RS), Brazil, a new mutant orange originating from natural mutation was identified and selected as a seedless material. To determine the mechanisms involved in the absence of seeds, the reproductive structures of this new mutant by comparison with a Valencia sweet orange as control, a cultivar with a profusion of seeds, was analyzed in terms of meiotic behavior, meiotic index, pollen viability, in vitro germination, and ovule features to determine the grounds for seed absence. Other morphological analyzes allowed for visualizing the structures of normal appearance and size in both cultivars. Meiotic analysis identified chromosome normal pairing with a predominance of bivalents at diakinesis and metaphase 1. URS Campestre flowers at different developmental stages had anthers and ovaries whose dimensions are typical while pollen grain analysis pointed to a standard developmental pattern, normal meiosis, high viability (84 %) and elevated in vitro pollen tube germination rates (63 %). The cv. Valencia and URS Campestre ovules had a similar shape and morphology, sharing an anatropous orientation, and two integuments. In the internal ovule analyses of Valencia sweet oranges, normal embryo sac cells were identified: presence of one egg cell and two synergids, three antipodes and a bigger and central cell containing two polar nuclei. However, the analysis of ovules from URS Campestre reveals an apparent senescence or non-formation of an embryo sac, where only a few highly stained and collapsed cells could be identified. These results led to the conclusion that female sterility in URS Campestre, with a total absence of a female gametophyte, is the limiting factor for fertilization and seed production.


Assuntos
Análise Citogenética/veterinária , Sementes/embriologia , Sementes/genética , Infertilidade Feminina
4.
Sci. agric. ; 74(5): 371-377, Sept.-Oct. 2017. ilus, tab
Artigo em Inglês | VETINDEX | ID: vti-15637

Resumo

ABSTRACT: Seedlessness in fruit is a trait that is much sought after by juice making industries. Close to the city of São Sebastião do Caí, in the state of Rio Grande do Sul (RS), Brazil, a new mutant orange originating from natural mutation was identified and selected as a seedless material. To determine the mechanisms involved in the absence of seeds, the reproductive structures of this new mutant by comparison with a Valencia sweet orange as control, a cultivar with a profusion of seeds, was analyzed in terms of meiotic behavior, meiotic index, pollen viability, in vitro germination, and ovule features to determine the grounds for seed absence. Other morphological analyzes allowed for visualizing the structures of normal appearance and size in both cultivars. Meiotic analysis identified chromosome normal pairing with a predominance of bivalents at diakinesis and metaphase 1. URS Campestre flowers at different developmental stages had anthers and ovaries whose dimensions are typical while pollen grain analysis pointed to a standard developmental pattern, normal meiosis, high viability (84 %) and elevated in vitro pollen tube germination rates (63 %). The cv. Valencia and URS Campestre ovules had a similar shape and morphology, sharing an anatropous orientation, and two integuments. In the internal ovule analyses of Valencia sweet oranges, normal embryo sac cells were identified: presence of one egg cell and two synergids, three antipodes and a bigger and central cell containing two polar nuclei. However, the analysis of ovules from URS Campestre reveals an apparent senescence or non-formation of an embryo sac, where only a few highly stained and collapsed cells could be identified. These results led to the conclusion that female sterility in URS Campestre, with a total absence of a female gametophyte, is the limiting factor for fertilization and seed production.(AU)


Assuntos
Sementes/embriologia , Sementes/genética , Análise Citogenética/veterinária , Infertilidade Feminina
5.
Tese em Português | VETTESES | ID: vtt-212013

Resumo

Paspalum notatum, gramínea nativa do Rio Grande do Sul, se destaca pelo elevado valor forrageiro e é importante em programas de melhoramento, pois se reproduz tanto de forma apomítica quanto sexual. Seu uso nas pastagens pode ser incrementado e explorado economicamente, após avaliações reprodutivas conduzidas em laboratório, e cultivos a campo, com a finalidade de selecionar os genótipos mais produtivos e estáveis reprodutivamente. O presente trabalho teve como objetivo avaliar uma progênie híbrida intraespecífica de P. notatum quanto ao modo de reprodução, viabilidade polínica e comportamento meiótico e avaliar o seu potencial produtivo em ensaios conduzidos a campo. Após comprovada a estabilidade reprodutiva e selecionados os híbridos com comprovado valor agronômico, será possível viabilizar novos ciclos de cruzamentos artificiais controlados. A poliploidização de plantas sexuais diploides foi usada em cruzamentos intraespecíficos entre genótipos apomíticos e sexuais, que gerou a progênie híbrida estudada. As avaliações agronômicas foram conduzidas durante três anos, comparando a progênie com a cultivar Pensacola, o ecótipo Bagual e as plantas poliploides artificiais WKS3, WKS63 e WKS92. As análises estatísticas foram efetuadas com o programa estatístico R, com os testes de Scott-Knott a 5% de significância. Todas as 29 plantas obtidas foram classificadas como apomíticas ou sexuais e apresentaram alta viabilidade polínica, a maioria acima de 90%. As plantas que mais produziram MSF (massa seca de folhas) foram as nominadas KF4, KF17, KM2 e KD9, produzindo, em média, 34, 24, 21 e 17%, respectivamente, a mais de massa seca do que o ecótipo mais produtivo Bagual. Os híbridos com características superiores, como o maior rendimento de forragem, passarão por etapas adicionais no programa de melhoramento e poderão ser candidatas a novas cultivares.


Paspalum notatum, native grass of Rio Grande do Sul, stands out for its high forage value and is important in breeding programs, as it reproduces both apomictically and sexually. Its use in the pastures can be increased and economically exploited, after reproductive evaluations conducted in the laboratory, and field crops, in order to select the most productive and reproductively stable genotypes. The aim of the present work was to evaluate an intraspecific hybrid progeny of P. notatum on reproduction mode, pollen viability and meiotic behavior and to evaluate its productive potential in field trials. After proven reproductive stability and selected hybrids with proven agronomic value, it will be possible to make possible new cycles of controlled artificial crosses. Polyploidization of diploid sex plants was used in intraspecific crosses between apomictic and sexual genotypes, which generated the hybrid progeny studied. The agronomic evaluations were conducted over three years, comparing the progeny with the "Pensacola" cultivar, the "Bagual" ecotype and the artificial polyploid plants 'WKS3', 'WKS63' and 'WKS92'. Statistical analyzes were performed with the statistical program R, with Scott-Knott's tests at 5% significance. All 29 plants obtained were classified as apomictic or sexual and presented high pollen viability, most of them above 90%. The plants that produced the most MSF were: 'KF4', 'KF17', 'KM2' and 'KD9', producing on average 34, 24, 21 and 17%, respectively, of more than than the most productive "Bagual" ecotype. Hybrids with superior characteristics, such as higher forage yield, will go through additional stages in the breeding program and may be candidates for new cultivars.

6.
Ci. Rural ; 39(5)2009.
Artigo em Português | VETINDEX | ID: vti-706272

Resumo

The purpose of this study was to evaluate the in vitro pollen germination of interespecifics hybrids between caiaué and oil palm (varieties dura, tenera and pisifera). The percentage of pollen germination (PPG) of hybrids ranged from 54.8% to 58.3%. The averages of hybrids and caiaué (73.1%) did not differ statistically, but were lower than the oil palm (84.8%). The germination of pollen of hybrids is sufficient for the successful of crosses in interespecific breeding programmes between caiaué and oil palm.


O objetivo deste estudo foi avaliar a germinação in vitro de pólen de híbridos interespecíficos entre o caiaué e o dendezeiro das variedades dura, pisífera e tenera. O percentual de germinação de pólen (PGP) dos híbridos variou de 54,8 a 58,3%. As médias dos híbridos e do caiaué (73,1%) não diferiram estatisticamente entre si, mas foram inferiores ao do dendezeiro (84,8%). A germinação de pólen dos híbridos é suficiente para o sucesso na realização de cruzamentos, nos programas de melhoramento interespecífico entre as espécies caiaué e dendezeiro.

7.
Ci. Rural ; 39(5)2009.
Artigo em Português | VETINDEX | ID: vti-705983

Resumo

The purpose of this study was to evaluate the in vitro pollen germination of interespecifics hybrids between caiaué and oil palm (varieties dura, tenera and pisifera). The percentage of pollen germination (PPG) of hybrids ranged from 54.8% to 58.3%. The averages of hybrids and caiaué (73.1%) did not differ statistically, but were lower than the oil palm (84.8%). The germination of pollen of hybrids is sufficient for the successful of crosses in interespecific breeding programmes between caiaué and oil palm.


O objetivo deste estudo foi avaliar a germinação in vitro de pólen de híbridos interespecíficos entre o caiaué e o dendezeiro das variedades dura, pisífera e tenera. O percentual de germinação de pólen (PGP) dos híbridos variou de 54,8 a 58,3%. As médias dos híbridos e do caiaué (73,1%) não diferiram estatisticamente entre si, mas foram inferiores ao do dendezeiro (84,8%). A germinação de pólen dos híbridos é suficiente para o sucesso na realização de cruzamentos, nos programas de melhoramento interespecífico entre as espécies caiaué e dendezeiro.

8.
Artigo em Português | LILACS-Express | VETINDEX | ID: biblio-1477654

Resumo

The purpose of this study was to evaluate the in vitro pollen germination of interespecifics hybrids between caiaué and oil palm (varieties dura, tenera and pisifera). The percentage of pollen germination (PPG) of hybrids ranged from 54.8% to 58.3%. The averages of hybrids and caiaué (73.1%) did not differ statistically, but were lower than the oil palm (84.8%). The germination of pollen of hybrids is sufficient for the successful of crosses in interespecific breeding programmes between caiaué and oil palm.


O objetivo deste estudo foi avaliar a germinação in vitro de pólen de híbridos interespecíficos entre o caiaué e o dendezeiro das variedades dura, pisífera e tenera. O percentual de germinação de pólen (PGP) dos híbridos variou de 54,8 a 58,3%. As médias dos híbridos e do caiaué (73,1%) não diferiram estatisticamente entre si, mas foram inferiores ao do dendezeiro (84,8%). A germinação de pólen dos híbridos é suficiente para o sucesso na realização de cruzamentos, nos programas de melhoramento interespecífico entre as espécies caiaué e dendezeiro.

9.
Ci. Rural ; 38(6)2008.
Artigo em Inglês | VETINDEX | ID: vti-705544

Resumo

Cytogenetic characterization was carried out on 12 accessions from Aster squamatus (Spreng.) Hieron., Pterocaulon polystachyum DC, and Solidago microglossa DC by studying their meiotic behavior and pollen viability. These species are from the Asteraceae family, native to Rio Grande do Sul State, Brazil, and are important for medicinal use. Young inflorescences with four accessions of each species were collected, fixed in ethanol-acetic acid (3:1), and conserved in ethanol 70% until use. The method used was that of squashing the anthers and coloring with acetic orcein 2%. Meiosis was regular in all accessions, presenting chromosomal associations preferentially bivalent, where n=10 was found for Aster squamatus and n=9 for Pterocaulon polystachyum, and Solidago microglossa. The studied accessions presented a Meiotic Index (MI) that varied from 65% to 87% in Aster squamatus, 85% to 92% in Pterocaulon polystachyum, and 64% to 92% in Solidago microglossa, indicating meiotic stability, although irregularities appeared during the cellular division. The pollen viability estimative was high in all studied accessions. These results indicate that the studied species can be included in future studies of genetic breeding.


Foi realizada a caracterização citogenética de doze acessos de Aster squamatus, Pterocaulon polystachyum e Solidago microglossa, espécies da família Asteraceae, nativas do Rio Grande do Sul, Brasil, por meio do estudo do comportamento meiótico e da viabilidade polínica, que possuem grande importância para uso medicinal. Inflorescências jovens de quatro acessos de cada espécie foram fixadas em álcool-ácido acético (3:1) e conservadas em álcool 70% até o uso. O método utilizado foi o de esmagamento de anteras e a coloração com orceína acética 2%. A meiose foi regular em todos os acessos, apresentando associações cromossômicas preferencialmente em bivalentes, encontrando-se n=10 para Aster squamatus e n=9 para Pterocaulon polystachyum e Solidago microglossa. Os acessos apresentaram índice meiótico que variou de 65% a 87% em Aster squamatus, de 85% a 92% em Pterocaulon polystachyum e de 64% a 92% para Solidago microglossa, indicando estabilidade meiótica, apesar de o aparecimento de irregularidades durante a divisão celular. A estimativa da viabilidade polínica foi alta para todos os acessos estudados. Esses resultados indicam que as espécies estudadas podem ser incluídas em futuros trabalhos de melhoramento genético.

10.
Artigo em Inglês | LILACS-Express | VETINDEX | ID: biblio-1477293

Resumo

Cytogenetic characterization was carried out on 12 accessions from Aster squamatus (Spreng.) Hieron., Pterocaulon polystachyum DC, and Solidago microglossa DC by studying their meiotic behavior and pollen viability. These species are from the Asteraceae family, native to Rio Grande do Sul State, Brazil, and are important for medicinal use. Young inflorescences with four accessions of each species were collected, fixed in ethanol-acetic acid (3:1), and conserved in ethanol 70% until use. The method used was that of squashing the anthers and coloring with acetic orcein 2%. Meiosis was regular in all accessions, presenting chromosomal associations preferentially bivalent, where n=10 was found for Aster squamatus and n=9 for Pterocaulon polystachyum, and Solidago microglossa. The studied accessions presented a Meiotic Index (MI) that varied from 65% to 87% in Aster squamatus, 85% to 92% in Pterocaulon polystachyum, and 64% to 92% in Solidago microglossa, indicating meiotic stability, although irregularities appeared during the cellular division. The pollen viability estimative was high in all studied accessions. These results indicate that the studied species can be included in future studies of genetic breeding.


Foi realizada a caracterização citogenética de doze acessos de Aster squamatus, Pterocaulon polystachyum e Solidago microglossa, espécies da família Asteraceae, nativas do Rio Grande do Sul, Brasil, por meio do estudo do comportamento meiótico e da viabilidade polínica, que possuem grande importância para uso medicinal. Inflorescências jovens de quatro acessos de cada espécie foram fixadas em álcool-ácido acético (3:1) e conservadas em álcool 70% até o uso. O método utilizado foi o de esmagamento de anteras e a coloração com orceína acética 2%. A meiose foi regular em todos os acessos, apresentando associações cromossômicas preferencialmente em bivalentes, encontrando-se n=10 para Aster squamatus e n=9 para Pterocaulon polystachyum e Solidago microglossa. Os acessos apresentaram índice meiótico que variou de 65% a 87% em Aster squamatus, de 85% a 92% em Pterocaulon polystachyum e de 64% a 92% para Solidago microglossa, indicando estabilidade meiótica, apesar de o aparecimento de irregularidades durante a divisão celular. A estimativa da viabilidade polínica foi alta para todos os acessos estudados. Esses resultados indicam que as espécies estudadas podem ser incluídas em futuros trabalhos de melhoramento genético.

11.
Braz. j. biol ; 66(1)2006.
Artigo em Inglês | LILACS-Express | LILACS, VETINDEX | ID: biblio-1467785

Resumo

Reproductive studies were carried out on Brazilian accessions of ipecac, Cephaelis ipecacuanha. Meiotic behavior was studied using the squashing technique. Irregular chromosome segregation in meiosis I and II, many sets of chromosomes in telophase II, micronuclei, incorrect cytoplasm division, incomplete cytokinesis and anomalous post-meiotic products, mainly polyads, were observed. The mean meiotic index was lower than 72%. Pollen viability was analyzed using Alexander solution, and the percentages ranged between brevistylous and longistylous floral morphs (85.3 to 93.1%), and among different localities (82.5 to 92.6%) analyzed. The size of pollen ranged between viable and sterile, and empty and shrunken sterile. In its natural habitat, this species is known to propagate by vegetative multiplication, but sexual reproduction seems to be as important as the vegetative propagation to this species.


Estudos reprodutivos foram realizados em acessos brasileiros de poaia, Cephaelis ipecacuanha. O comportamento meiótico foi estudado usando a técnica de esmagamento. Foi observada segregação irregular de cromossomos durante meiose I e II, muitos grupos de cromossomos em telófase II, micronúcleos, divisão incorreta do citoplasma, citocinese incompleta e produtos pós-meióticos anômalos, principalmente políades. A média do índice meiótico foi inferior a 72%. A viabilidade polínica foi analisada utilizando-se solução de Alexander e a percentagem de pólen viável variou entre as formas florais, brevistila e longistila (85,3% a 93,1%), e entre as diferentes localidades (82,5% a 92,6%) analisadas. O tamanho do pólen variou entre viáveis e inviáveis, e entre os inviáveis vazios e contraídos. Em seu habitat natural, a poaia apresenta propagação por multiplicação vegetativa, mas a reprodução sexuada parece ser tão importante para essa espécie quanto a propagação vegetativa.

12.
Braz. J. Biol. ; 66(1)2006.
Artigo em Inglês | VETINDEX | ID: vti-446081

Resumo

Reproductive studies were carried out on Brazilian accessions of ipecac, Cephaelis ipecacuanha. Meiotic behavior was studied using the squashing technique. Irregular chromosome segregation in meiosis I and II, many sets of chromosomes in telophase II, micronuclei, incorrect cytoplasm division, incomplete cytokinesis and anomalous post-meiotic products, mainly polyads, were observed. The mean meiotic index was lower than 72%. Pollen viability was analyzed using Alexander solution, and the percentages ranged between brevistylous and longistylous floral morphs (85.3 to 93.1%), and among different localities (82.5 to 92.6%) analyzed. The size of pollen ranged between viable and sterile, and empty and shrunken sterile. In its natural habitat, this species is known to propagate by vegetative multiplication, but sexual reproduction seems to be as important as the vegetative propagation to this species.


Estudos reprodutivos foram realizados em acessos brasileiros de poaia, Cephaelis ipecacuanha. O comportamento meiótico foi estudado usando a técnica de esmagamento. Foi observada segregação irregular de cromossomos durante meiose I e II, muitos grupos de cromossomos em telófase II, micronúcleos, divisão incorreta do citoplasma, citocinese incompleta e produtos pós-meióticos anômalos, principalmente políades. A média do índice meiótico foi inferior a 72%. A viabilidade polínica foi analisada utilizando-se solução de Alexander e a percentagem de pólen viável variou entre as formas florais, brevistila e longistila (85,3% a 93,1%), e entre as diferentes localidades (82,5% a 92,6%) analisadas. O tamanho do pólen variou entre viáveis e inviáveis, e entre os inviáveis vazios e contraídos. Em seu habitat natural, a poaia apresenta propagação por multiplicação vegetativa, mas a reprodução sexuada parece ser tão importante para essa espécie quanto a propagação vegetativa.

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