MARCADORES ANATÔMICOS DO PECÍOLO E A TOLERÂNCIA À SECA DE PONTEIROS E AO DÉFICIT HÍDRICO EM EUCALIPTO

A seca de ponteiros em Eucalipto é um distúrbio fisiológico, onde o estresse hídrico vem sendo associado como um dos fatores intensificadores de sua ocorrência. A seleção precoce de genótipos de eucalipto tolerantes a essas condições, podem fornecer informações relevantes quanto a esse distúrbio. Objetivou-se avaliar possíveis marcadores anatômicos, associados a tolerância ao déficit hídrico e à seca de ponteiros. Genótipos comerciais com diferentes graus de suscetibilidade a seca de ponteiros foram submetidos a diferentes níveis de estresse hídrico em condições de casa de vegetação. A duração do experimento foi de 75 dias. Amostras de pecíolos foram coletadas e avaliadas as características das áreas anatômicas de: seção transversal, tecido vascular, xilema, floema e do córtex. Os dados foram submetidos à análise da variância (ANOVA) e para comparação de médias foi adotado o teste Tukey (p<0,05). Os resultados mostraram que há a tendência de redução de todas as variáveis avaliadas com o aumento do déficit hídrico. Entretanto, o genótipo tolerante em condições de maior restrição hídrica apresenta maior área de seção transversal e de tecidos condutores em comparação ao suscetível. A maior proporção destes tecidos sugere que o clone tolerante apresenta condição mais favorável ao transporte de água, fotoassimilados e nutrientes. Palavras-chave: melhoramento florestal; silvicultura; seleção genômica.   ANATOMICAL MARKERS OF PETIOLE AND TOLERANCE TO DIE-BACK AND WATER STRESS IN EUCALYPTUS   ABSTRACT: Die-Back in Eucalyptus is a physiological disorder where the water stress has been associated as an intensifier of this occurrence. The early selection of tolerant Eucalyptus genotypes to water stress can provide relevant information to this disorder. The research aimed to evaluate possible anatomical markers associated with tolerance to water stress and Die-Back. Commercial genotypes with different levels of susceptibility to this disorder were submitted to different levels of water stress in a greenhouse condition. The experiment lasted 75 days. Petioles samples were collected and anatomical characteristics were evaluated: cross-sectional area, area of vascular tissue, xylem area, phloem area and cortical area. The data were submitted to analysis of variance (ANOVA) and for the comparison of means was adopted Tukey test (p <0.05). The results show us that there is a tendency to reduce all variables with increasing water deficit. However, the tolerant genotype in higher water stress conditions has greater cross-sectional area and conducting tissues compared to susceptible genotype. The major proportion of these tissues suggests that the tolerant clone presents more favorable condition for transport of water, nutrients and assimilates. Keywords: forest improvement; forestry; genomic selection

Accelerated in vitro propagation of elite oil palm genotypes (Elaeis guineensis Jacq.) by substituting cytokinin with putrescine

Clonal multiplication of oil palm enables the formation of commercial plantations with higher yield, which is possible through somatic embryogenesis. However, due to different modifications made in the existing protocols to avoid the appearance of the “mantled flower”, the success of this technique has been limited. Thus, this study aimed to apply a cloning protocol, using somatic embryogenesis, to 32 elite oil palm genotypes from a commercial plantation on which cytokinin was substituted with putrescine. All tested genotypes responded positively to callus induction. Moreover, the percentages of responses were differentiated: 65.62% of these genotypes produced embryogenic lines, and 40.62% out of that percentage presented lines with moderate or high multiplication capacity, which is the main factor that enabled the obtaining of clones to form a commercial clonal plantation. The somatic embryogenesis was efficient, making this protocol applicable at a commercial scale, since it allows the obtaining of clones up to 360 days. However, future evaluations on these clones are needed to investigate the appearance of the “mantled flower”.Keywords: Cloning, polyamines, tissue culture, commercial plantatio

In vitro morphogenesis and optimization of the number of RAPD markers for the estimation of the eucalypt genetic diversity

Foram conduzidos experimentos de cultura de tecidos utilizando um genótipo híbrido de Eucalyptus grandis vs. E. smithii e sementes de um cruzamento controlado de E. grandis. Foram isoladas uma levedura e uma bactéria que têm dificultado a cultura in vitro e transformação genética do genótipo híbrido, sendo a bactéria identificada como Herbaspirillum huttiense (Leifson) Ding e Yokota. Dentre 34 antibióticos testados in vitro para o controle do crescimento de H. huttiense, 12 induziram halos de inibição. Sulfadiazina, estreptomicina, canamicina e penicilina foram selecionados para determinação da concentração inibitória mínima. Sulfadiazina, estreptomicina e canamicina induziram halos de inibição entre as concentrações de 256 e 512 mg L -1 , contudo, apresentaram apenas atividade bacteriostática. Penicilina não apresentou efeito bactericida ou bacteriostático em concentrações até 1024 mg L -1 . Cefotaxima, carbenicilina e timentin foram avaliados quanto ao seu efeito sobre a morfogênese in vitro de explantes de Eucalyptus grandis. Foi observado que carbenicilina e timentin, em concentrações até 600 mg L -1 , favoreceram a freqüência de explantes regenerando calos (50-70%) e a redução da necrose. Cefotaxima beneficiou a calogênese até 300 mg L -1 , concentração a partir da qual promoveu aumento dos calos necrosados (>60%). Explantes cotiledonares e de hipocótilos de E. grandis foram submetidos a altas concentrações de diferentes reguladores de crescimento (ABSA, AIA, AIB, ANA, 2,4-D, TDZ, ZEA, BAP e KIN) e a combinações de 10, 50 e 100 mg L -1 de 2,4-D e períodos de exposição de 6, 12, 24 e 48 horas. Plântulas intactas apresentaram resultados superiores (~7 raízes/explante) quanto à rizogênese adventícia comparadas a hipocótilos e cotilédones isolados (10 raízes/explante), enquanto TDZ, ZEA, BAP e KIN inibiram (60%). E. grandis hypocotyl and cotyledon explants were submitted to high concentrations of different growth regulators (BSAA, IAA, IBA, NAA, 2,4- xiiD, TDZ, ZEA, BAP and KIN), and to combinations of 10, 50 and 100 mg L -1 2,4-D and 6, 12, 24 and 48 hours pre-treatment periods. Intact plantlets displayed superior adventitious rhizogenesis (~7 roots/explant) compared to isolated hypocotyl and cotyledon explants (10 roots/explant) whereas TDZ, ZEA, BAP and KIN significantly inhibited (<1 roots/explant) adventitious rhizogenesis. Epicotyl elongation was also significantly inhibited by TDZ, KIN, 2,4-D, BAP and BSAA, while IAA, IBA, NAA and ZEA did not. BSAA displayed a significantly higher effect on adventitious root induction, even compared to IBA. Epicotyl elongation and average number of roots per explant declined, whereas explant necrosis augmented, with higher 2,4-D exposures and concentrations. In the molecular marker studies, the profiles of 84 Eucalyptus genotypes based on RAPD markers were determined. A total of 501 bands was generated, from which 450 (89.82%) were polymorphic and 51 (10.18%) monomorphic. Two hundred bootstrap analysis revealed that a number higher than 393 markers provided values below 5% for stress, lower than 5 for sum of squares and higher than 0.95 for correlation statistics. Comparing the genetic diversity indexes between and within the E. grandis and E. urophylla sub-populations, most of the variability was found in the sub-populations. Except for the Shannon index, other variability indexes increased as monomorphic markers were withdrawn from the analysis. Nevertheless, clustering analysis based on RAPD markers demonstrated association with taxonomic classification.Coordenação de Aperfeiçoamento de Pessoal de Nível Superio

Efeito "in vitro" de antibióticos e rizobactérias no controle de bactérias fitopatogênicas ao Eucalyptus spp

Doenças causadas por bactérias constituem um novo desafio à cultura do Eucalyptus spp., podendo, inclusive, limitar o uso de clones suscetíveis. O presente trabalho objetivou avaliar a eficiência de antibióticos e rizobactérias na inibição do crescimento "in vitro" de isolados de bactérias fitopatogênicas ao Eucalyptus spp. na fase de viveiro e de campo. O antibiótico sulfato de amicacina e a rizobactéria S1 (Bacillus subtillis) destacaram-se quanto à inibição do crescimento do isolado fitopatogênico IP1-05 (Pseudomonas chichorii), enquanto a cefoxitina causou maior inibição dos isolados BSV16 e RVV11 (Rhizobium sp.). Os antibióticos de uso comercial na área agronômica, Mycoshield (oxitetraciclina) e Agrimicina (estreptomicina e tetraciclina) foram pouco efetivos. Este trabalho proporciona embasamento a alternativas para controle biológico de doenças bacterianas em mudas de Eucalyptus spp. na fase de viveiro.Diseases caused by bacteria represent a new challenge for Eucalyptus spp. and may also limit the use of susceptible clones. Our study aimed at an evaluation of the efficiency of antibiotics and rhizobacteria in inhibiting "in vitro" growth of phytopathogenic bacteria isolates in Eucalyptus spp. during the nursery stage and in the field. The antibiotic amicacine sulfate and rhizobacterium S1 (Bacillus subtilis) stood out inhibiting the growth of the phytopathogenic isolate IP1-05 (Pseudomonas chichorii), whereas cefoxitin caused a greater inhibition of the isolates BSV16 and RVV11 (Rhizobium sp.). The commercial antibiotics for agricultural use Mycoshield (oxitetracycline) and Agrimycin (estreptomycin and tetracycline) were little effective. This study offers a base for alternatives of biological control of bacterial diseases in Eucalyptus spp. nursery seedlings

MARCADORES ANATÔMICOS DO PECÍOLO E A TOLERÂNCIA À SECA DE PONTEIROS E AO DÉFICIT HÍDRICO EM EUCALIPTO

A seca de ponteiros em Eucalipto é um distúrbio fisiológico, onde o estresse hídrico vem sendo associado como um dos fatores intensificadores de sua ocorrência. A seleção precoce de genótipos de eucalipto tolerantes a essas condições, podem fornecer informações relevantes quanto a esse distúrbio. Objetivou-se avaliar possíveis marcadores anatômicos, associados a tolerância ao déficit hídrico e à seca de ponteiros. Genótipos comerciais com diferentes graus de suscetibilidade a seca de ponteiros foram submetidos a diferentes níveis de estresse hídrico em condições de casa de vegetação. A duração do experimento foi de 75 dias. Amostras de pecíolos foram coletadas e avaliadas as características das áreas anatômicas de: seção transversal, tecido vascular, xilema, floema e do córtex. Os dados foram submetidos à análise da variância (ANOVA) e para comparação de médias foi adotado o teste Tukey (p&lt;0,05). Os resultados mostraram que há a tendência de redução de todas as variáveis avaliadas com o aumento do déficit hídrico. Entretanto, o genótipo tolerante em condições de maior restrição hídrica apresenta maior área de seção transversal e de tecidos condutores em comparação ao suscetível. A maior proporção destes tecidos sugere que o clone tolerante apresenta condição mais favorável ao transporte de água, fotoassimilados e nutrientes. Palavras-chave: melhoramento florestal; silvicultura; seleção genômica.   ANATOMICAL MARKERS OF PETIOLE AND TOLERANCE TO DIE-BACK AND WATER STRESS IN EUCALYPTUS   ABSTRACT: Die-Back in Eucalyptus is a physiological disorder where the water stress has been associated as an intensifier of this occurrence. The early selection of tolerant Eucalyptus genotypes to water stress can provide relevant information to this disorder. The research aimed to evaluate possible anatomical markers associated with tolerance to water stress and Die-Back. Commercial genotypes with different levels of susceptibility to this disorder were submitted to different levels of water stress in a greenhouse condition. The experiment lasted 75 days. Petioles samples were collected and anatomical characteristics were evaluated: cross-sectional area, area of vascular tissue, xylem area, phloem area and cortical area. The data were submitted to analysis of variance (ANOVA) and for the comparison of means was adopted Tukey test (p &lt;0.05). The results show us that there is a tendency to reduce all variables with increasing water deficit. However, the tolerant genotype in higher water stress conditions has greater cross-sectional area and conducting tissues compared to susceptible genotype. The major proportion of these tissues suggests that the tolerant clone presents more favorable condition for transport of water, nutrients and assimilates. Keywords: forest improvement; forestry; genomic selection

A priori choice of hybrid parents in plants

Não encontrei o DOI do artigo.Plant breeding deals with high-yielding genotypes. However, how best to choose parents of these genotypes remains an unsolved question. Here, we focus on a priori choice based on parental distances by means of agronomic and molecular data. Despite numerous theoretical and empirical studies, a priori choice continues to be a controversial procedure. Both success and failure are commonly reported. We looked at these ambiguous results in order to investigate their possible causes. A total of 139 articles on genetic divergence were sampled to examine aspects such as type and number of markers utilized. We suggest that the mean number of 160, 281 and 25 for RAPD and RFLP markers, and SSR loci, respectively, which we found in these papers, should be increased for accurate analysis. A second sample composed of 54 articles was used to evaluate the divergence-heterosis association. Most of them (28) detected positive divergence-heterosis association, whereas 26 revealed negative or inconclusive results. We examined several causes that influence a priori choice positively and negatively

Diversidade genética de populações naturais de Pfaffia glomerata (Spreng.) Pedersen estimada por marcadores RAPD - DOI: 10.4025/actasciagron.v31i3.548

Pfaffia glomerata is a native species from South America, occurring naturally in some states of Brazil. The ever growing interest by the species, mainly due to its important therapeutic properties, has threatened the natural populations, as exploitation has occurred in a rather predatory way. The present study aimed to compare the genetic diversity of four natural populations originated from of the area of the Paraná River basin (Paraná and Mato Grosso States). The individuals were propagated in vitro and characterized by means of RAPD markers. A total of 267 polymorphic marks were obtained from 67 primers. The genetic distance estimates were obtained based on the complement arithmetic of Nei and Li’s similarity coefficient, and the genotypes were grouped according to the UPGMA method. Three populations from the margin of the Paraná River and at Mineiro Island presented low diversity levels among them, though possessing the same propagule dispersal flow. The population located in the proximities of the margin of the Ivaí river (tributary of the river Paraná) presented greater diversity values within and among the populations, suggesting that its preservation should be a priority and that the origin of the genetic variability may be related to the dispersion flow of the vegetative propagules.Pfaffia glomerata é uma espécie nativa da América do Sul e de ocorrência natural em alguns Estados do Brasil. Porém, as populações naturais de fáfia têm sido ameaçadas em decorrência do intenso extrativismo, em virtude de suas propriedades terapêuticas de interesse. No presente estudo, objetivou-se estimar a diversidade genética de quatro populações naturais oriundas da bacia do Rio Paraná. Os indivíduos foram multiplicados in vitro e caracterizados de acordo com o padrão eletroforético de marcadores RAPD, utilizando-se 268 marcas polimórficas obtidas a partir de 67 primers. As estimativas de distância genética foram obtidas pelo complemento aritmético do coeficiente de Nei e Li, e os genótipos agrupados de acordo com o método UPGMA. Três populações situadas próximas às margens do rio Paraná e na ilha do Mineiro apresentaram baixos índices de diversidade entre elas, e estas possuem o mesmo fluxo de dispersão dos propágulos. A população situada nas proximidades da margem do rio Ivaí (afluente do rio Paraná) apresentou maiores valores de diversidade dentro da população e entre as populações, indicando que sua preservação é prioritária e a origem da variabilidade pode estar relacionada ao fluxo de dispersão de propágulos

Tree Species and Morphology of Holes Caused by Black-Tufted Marmosets to Obtain Exudates: Some Implications for the Exudativory

Knowledge of the pattern of exploitation of trees can help us understand the relationship between marmosets and plants, especially in declining forests, such as those in the Brazilian Cerrado. Black-tufted marmosets (Callithrix penicillata) regularly exploit exudates by gouging the bark of trees with their specialized teeth. Determining preferred tree species to exploit exudates is important for forest management aimed at maintaining an essential food source for urban marmosets. We characterized the tree species, dendrometry, and the characteristics of the holes made by marmosets to obtain exudates. Based on these data, we proposed a gouging effort index (Chiseling Suitability Index for Marmosets, ChiSI). We identified 16 species belonging to 10 families of trees with gouging marks made by marmosets. Eleven new tree species used by black-tufted marmosets for exudates were identified in urban forests in the Cerrado. Exudate exploration was predominantly of medium intensity, with round holes concentrated in the canopy. The species Tapirira guianensis and Croton urucarana were preferred. The ChiSI was characterized by a narrow range for both T. guianensis and C. urucarana. Despite the flexibility of obtaining exudates, the black-tufted marmosets concentrate their exploitation to only a few tree species. The T. guianensis and C. urucarana tree species should be considered the most important species for management plans and the preservation of black-tufted marmosets that live in urban forests in the Cerrado

Physiological quality, anatomy and histochemistry during the development of carrot seeds ( Daucus carota L.)

ABSTRACT The adequate time for carrot seed harvest influences its physiological quality. The objective of this study was to evaluate physiological, anatomical and histochemical changes in carrot seeds harvested at different stages of development and to establish the most appropriate harvest time. Secondary umbels were harvested at 14, 21, 28, 35, 42, 49, 56 and 63 days after anthesis (DAA). For seed anatomical and histochemical characterization, sections were stained with Toluidine blue stain, Xylidine Ponceau, Lugol’s iodine, Sudan Black B and submitted to polarized light. Seed moisture content, seed dry matter, germination, first count, emergence percentage and emergence speed index of seedlings were evaluated. Cultivar Brasília carrot seeds at 14 DAA are in cell division and expansion. In addition, as lipids were identified in the endosperm, despite the seed low dry matter. At 21 DAA, reserve substances such as protein and starch were also identified. Along the seed development process, deposition of lignin occurs in the endocarp cells, and this collapsed lignified layer represents the resistance layer of the seeds. Physiological maturity, represented by the maximum dry matter accumulation, occurs at 35 DAA, with the endosperm occupying almost all volume of seeds, the embryo occupying a small cylindrical region and the integument showing a single layer of cells. At this time, the seeds presented 56% moisture content and the color of the pericarp is green-yellow. Maximum seed germination and vigor occurred at 30 DAA, just before physiological maturity was reached (35 DAA). Thus, the ideal time to harvest the seeds of cultivar Brasília is from 30 DAA, where the seeds have maximum physiological quality