RESUMO
Diversification of rootstock varieties, with consequent reduction in phytosanitary risks, has great importance to the sustainability of citrus cultivation in the south of Brazil. This study evaluated the performance of 42 rootstocks in the nursery phase to generate 'Valencia Late' sweet orange seedlings. Therefore, nucellar seedlings from the rootstocks under study were analyzed in relation to plant height, stem diameter, mortality rate and percentage of bud set after grafting. The experimental design was completely randomized with four replications of 20 sample units. Not adapted genotypes had high mortality rates, and the ones of both hybrids LCR x CTSW - 009 and LVK x LCR - 038 were 100% and 90%, respectively. Other 13 genotypes had mortality rates above 30%, and 'Sunki' mandarin was the female genitor of ten of them. 'Swingle' citrumelo was the rootstock with the highest development (plant height and stem diameter), associated with low mortality rate. In relation to the other rootstocks, the best results were the fast grafting diameter, associated with low mortality rate obtained by hybrids HTR - 053, LRF x (LCR x TR) - 005, CLEO x TRBN - 245, CLEO x TRSW - 287, and citrandarins Indio, Riverside and San Diego, as well as Trifoliate orange and Rangpur lime. In addition to Trifoliate orange, which is widely used in Rio Grande do Sul, these rootstocks have great potential in citriculture in the south of Brazil.
A diversificação do uso de variedades porta-enxerto, com a consequente redução de riscos fitossanitários, é de fundamental importância para a sustentabilidade da citricultura do Sul do Brasil. O objetivo deste trabalho foi avaliar o comportamento de 42 porta-enxertos na formação de mudas de laranjeira 'Valência Late' em fase de viveiro. Nesse sentido, seedlings (plantas oriundas da germinação de sementes) nucelares dos porta-enxertos estudados foram avaliados relativamente aos caracteres altura da planta, diâmetro do caule, taxa de mortalidade e percentagem de pegamento de borbulhas após a enxertia. O delineamento experimental foi inteiramente casualizado, com quatro repetições de 20 unidades amostrais. Genótipos não adaptados tiveram altas taxas de mortalidade, os híbridos LCR x CTSW - 009 e LVK x LCR - 038 apresentaram 100% e 90% de mortalidade, respectivamente. Mais 13 genótipos apresentaram mortalidade superior a 30%, destes, dez têm como parental feminino a tangerineira 'Sunki'. O citrumelo 'Swingle' foi o porta-enxerto que apresentou maior desenvolvimento (altura da planta e diâmetro do caule), associado a uma baixa taxa de mortalidade. Quanto aos demais porta-enxertos, destacaram-se por atingir rapidamente o diâmetro de enxertia, associado a baixa taxa de mortalidade, os híbridos HTR - 053, LRF x (LCR x TR) - 005, CLEO x TRBN - 245, CLEO x TRSW - 287, citrandarins 'Indio', Riverside e San Diego, assim como o limoeiro 'Cravo' e o Trifoliata. Além do Trifoliata, amplamente utilizado no Rio Grande do Sul, estes porta-enxertos são promissores para a citricultura do Sul do Brasil.
Assuntos
Citrus sinensis/crescimento & desenvolvimento , Citrus sinensis/genética , Germinação/fisiologiaRESUMO
Diversification of rootstock varieties, with consequent reduction in phytosanitary risks, has great importance to the sustainability of citrus cultivation in the south of Brazil. This study evaluated the performance of 42 rootstocks in the nursery phase to generate 'Valencia Late' sweet orange seedlings. Therefore, nucellar seedlings from the rootstocks under study were analyzed in relation to plant height, stem diameter, mortality rate and percentage of bud set after grafting. The experimental design was completely randomized with four replications of 20 sample units. Not adapted genotypes had high mortality rates, and the ones of both hybrids LCR x CTSW - 009 and LVK x LCR - 038 were 100% and 90%, respectively. Other 13 genotypes had mortality rates above 30%, and 'Sunki' mandarin was the female genitor of ten of them. 'Swingle' citrumelo was the rootstock with the highest development (plant height and stem diameter), associated with low mortality rate. In relation to the other rootstocks, the best results were the fast grafting diameter, associated with low mortality rate obtained by hybrids HTR - 053, LRF x (LCR x TR) - 005, CLEO x TRBN - 245, CLEO x TRSW - 287, and citrandarins Indio, Riverside and San Diego, as well as Trifoliate orange and Rangpur lime. In addition to Trifoliate orange, which is widely used in Rio Grande do Sul, these rootstocks have great potential in citriculture in the south of Brazil.(AU)
A diversificação do uso de variedades porta-enxerto, com a consequente redução de riscos fitossanitários, é de fundamental importância para a sustentabilidade da citricultura do Sul do Brasil. O objetivo deste trabalho foi avaliar o comportamento de 42 porta-enxertos na formação de mudas de laranjeira 'Valência Late' em fase de viveiro. Nesse sentido, seedlings (plantas oriundas da germinação de sementes) nucelares dos porta-enxertos estudados foram avaliados relativamente aos caracteres altura da planta, diâmetro do caule, taxa de mortalidade e percentagem de pegamento de borbulhas após a enxertia. O delineamento experimental foi inteiramente casualizado, com quatro repetições de 20 unidades amostrais. Genótipos não adaptados tiveram altas taxas de mortalidade, os híbridos LCR x CTSW - 009 e LVK x LCR - 038 apresentaram 100% e 90% de mortalidade, respectivamente. Mais 13 genótipos apresentaram mortalidade superior a 30%, destes, dez têm como parental feminino a tangerineira 'Sunki'. O citrumelo 'Swingle' foi o porta-enxerto que apresentou maior desenvolvimento (altura da planta e diâmetro do caule), associado a uma baixa taxa de mortalidade. Quanto aos demais porta-enxertos, destacaram-se por atingir rapidamente o diâmetro de enxertia, associado a baixa taxa de mortalidade, os híbridos HTR - 053, LRF x (LCR x TR) - 005, CLEO x TRBN - 245, CLEO x TRSW - 287, citrandarins 'Indio', Riverside e San Diego, assim como o limoeiro 'Cravo' e o Trifoliata. Além do Trifoliata, amplamente utilizado no Rio Grande do Sul, estes porta-enxertos são promissores para a citricultura do Sul do Brasil.(AU)
Assuntos
Citrus sinensis/crescimento & desenvolvimento , Citrus sinensis/genética , Germinação/fisiologiaRESUMO
Citrus trees produce flushes throughout the year, but there are no criteria established for a precise shoot monitoring in orchards under tropical climate. Methods for quantification of flush dynamics would be useful for horticultural and pest management studies because different insect vectors feed and reproduce on flushes. We estimated the minimum number and distribution of trees for sampling and determined the flushing pattern over time in 'Valencia Late' orange trees grafted onto 'Swingle' citrumelo rootstock. Shoots within a square frame (0.25 m2) on two sides of the canopy were counted and classified by their phenological stage. The minimum number of samples was estimated using the mean number of shoots and area under the flush shoot dynamics (AUFSD). The temporal and spatial distribution analysis was performed by Taylor's power law and by multiple correspondence analysis (MCA). Additionally, a shoot maturity index (SMI) based on visual qualitative assessment of flushes is proposed. Considering the mean number of shoots, it was necessary to sample two sides of 16 trees to reach a relative sampling error (Er) of 25%, whereas by the AUFSD, only five trees were necessary to reach an Er of 10%. Flushes were predominantly randomly distributed over time and space. Testing eight transects, sampled trees should be distributed throughout the block, avoiding sampling concentration in a certain area. MCA showed that the west side and the upper sampling positions of trees were more likely to be associated with younger shoots. AUFSD and the evaluation of both sides of the canopy yielded a smaller number of trees to be assessed. The SMI was a reliable metric to estimate the shoot phenology of orange trees, and correlated well (R2 > 70%) with the mean number of shoots within the square frame. Therefore, SMI has the potential to make shoot monitoring in the field more practical.
Assuntos
Citrus/crescimento & desenvolvimento , Animais , Brasil , Citrus/parasitologia , Citrus sinensis/crescimento & desenvolvimento , Citrus sinensis/parasitologia , Produtos Agrícolas/crescimento & desenvolvimento , Vetores de Doenças , Monitorização de Parâmetros Ecológicos , Interações Hospedeiro-Patógeno , Controle de Pragas/métodos , Doenças das Plantas/parasitologia , Doenças das Plantas/prevenção & controle , Brotos de Planta/crescimento & desenvolvimento , Tamanho da Amostra , Clima Tropical , Tempo (Meteorologia)RESUMO
BACKGROUND: Small RNAs regulate a wide variety of processes in plants, from organ development to both biotic and abiotic stress response. Being master regulators in genetic networks, their biogenesis and action is a fundamental aspect to characterize in order to understand plant growth and development. Three main gene families are critical components of RNA silencing: DICER-LIKE (DCL), ARGONAUTE (AGO) and RNA-DEPENDENT RNA POLYMERASE (RDR). Even though they have been characterized in other plant species, there is no information about these gene families in Citrus sinensis, one of the most important fruit species from both economical and nutritional reasons. While small RNAs have been implicated in the regulation of multiple aspects of plant growth and development, their role in the abscission process has not been characterized yet. RESULTS: Using genome-wide analysis and a phylogenetic approach, we identified a total of 13 AGO, 5 DCL and 7 RDR genes. We characterized their expression patterns in root, leaf, flesh, peel and embryo samples using RNA-seq data. Moreover, we studied their role in fruit abscission through gene expression analysis in fruit rind compared to abscission zone from samples obtained by laser capture microdissection. Interestingly, we determined that the expression of several RNA silencing factors are down-regulated in fruit abscission zone, being particularly represented gene components of the RNA-dependent DNA Methylation pathway, indicating that repression of this process is necessary for fruit abscission to take place in Citrus sinensis. CONCLUSIONS: The members of these 3 families present characteristic conserved domains and distinct expression patterns. We provide a detailed analysis of the members of these families and improved the annotation of some of these genes based on RNA-seq data. Our data suggests that the RNA-dependent DNA Methylation pathway is involved in the important fruit abscission process in C. sinensis.
Assuntos
Citrus sinensis/fisiologia , Metilação de DNA/fisiologia , Frutas/crescimento & desenvolvimento , Genes de Plantas/fisiologia , Genoma de Planta/fisiologia , Citrus sinensis/genética , Citrus sinensis/crescimento & desenvolvimento , Frutas/genética , Regulação da Expressão Gênica de Plantas , Família Multigênica , FilogeniaRESUMO
Citrus leprosis virus C (CiLV-C) is an economically important pathogen and the main causative agent of leprosis disease in citrus orchards. The main vector of this disease, the mite Brevipalpus yothersi, is widely distributed in Mexican orchards on a wide range of citrus species. Despite the importance of both the virus and the mite, field studies recording their occurrence and co-occurrence are practically non-existent. We systematically sampled orange orchards for both CiLV-C and B. yothersi throughout the year. The distribution of the CiLV-C and B. yothersi was evaluated on each sampling occasion and their spatiotemporal associations were determined. Specifically, 100-112 orange trees, distributed in 18 rows (five or six trees per row), were sampled monthly between March 2017 and February 2018 (11 sampling dates). Twenty leaves per tree were sampled on each occasion. The number of mites per tree and the percentage of leaves per tree with disease symptoms were recorded. On each sampling occasion, spatiotemporal associations between mites and disease were determined using the Spatial Analysis by Distance Indices (SADIE) method. CiLV-C and B. yothersi were identified using molecular methods. Throughout the study, the distribution of CiLV-C was aggregated and the distribution of B. yothersi was random. No association was found between the virus and the mite on any of the sampling dates. In total, 173 mites were collected, but only 43 mites were found to be carrying CiLV-C. The reason for this lack of association between the virus and the mite, as well as the impact of our findings on the epidemiology of the disease in orange orchards, are discussed.
Assuntos
Distribuição Animal , Ácaros/fisiologia , Vírus de Plantas/fisiologia , Animais , Citrus sinensis/crescimento & desenvolvimento , Citrus sinensis/fisiologia , Citrus sinensis/virologia , México , Doenças das Plantas/virologia , Folhas de Planta/fisiologia , Folhas de Planta/virologia , Dinâmica Populacional , Análise Espaço-TemporalRESUMO
The period of citrus black spot (CBS) control used in South Africa (SA) and Australia, from October to January or February, has not been as effective in São Paulo (SP), Brazil. This study aimed to evaluate different periods of protection and determine the critical period for CBS control in SP. A field trial was carried out for two seasons in a mature Valencia sweet orange orchard located in Mogi Guaçu, SP. Spray programs with a total of 60, 100, 140, 180, and 220 days of fruit protection (DFP) were evaluated. CBS symptoms and fruit drop decreased exponentially as the length of the period of protection increased. The reductions in CBS intensity and crop loss with these programs ranged from 34 to 96 and 50 to 77%, respectively. The programs with 180 and 220 DFP, which protected the fruit from September to March and May, showed the highest cost benefit. The critical period needed for CBS control in SP is longer than that in SA and Australia. The results obtained with the present study are helpful for scheduling a more efficient and rational program for CBS control not only in SP but also in other tropical and subtropical regions with similar weather conditions.
Assuntos
Ascomicetos/fisiologia , Citrus sinensis/microbiologia , Fungicidas Industriais/administração & dosagem , Doenças das Plantas/prevenção & controle , Brasil , Citrus sinensis/crescimento & desenvolvimento , Estações do AnoRESUMO
The cultivation of new types of oranges can be a good alternative for citrus growers because there is a growing domestic market and good export prospects. Due to these expectations, it is essential to search for new cultivars for use in the fresh fruit industry. Therefore, the aim of this work was to physicochemically characterize the fruits of new cultivars of Navel oranges, seeking alternatives with good characteristics, such as earliness, lack of seeds, good color and organoleptic characteristics desired by the consumer market. The fruits of five new cultivars of Navel orange were evaluated, namely, Bahia Valente (CN 28), Golden Nugget Navel (CN 41), Robertson Navel (CN 39), Washington Navel (CV 27) and Washington Navel I (CN 34), during two harvest seasons (2012/2013 and 2013/2014). The following physicochemical variables were quantified: mass, peel color, juice yield, acidity, soluble solids and ratio. The cultivars studied were compared to the commercial cultivar Bahia Cabula (CV 25). The new cultivars produced fruit with standards that met consumer expectations, with fruit mass suitable for sale of the fresh fruit, good yield juice and early maturation (March), which enables harvesting Bahia Cabula in the off-season period. Thus, it is concluded that there are navel orange cultivars with acceptable physicochemical qualities and early maturation.(AU)
O plantio de novos tipos de laranjas pode ser boa alternativa aos citricultores, pois há um mercado interno crescente e boas perspectivas de exportação. Em decorrência dessas expectativas torna-se primordial buscar novas variedades para o segmento de frutas frescas. Portanto, objetivou-se, com este trabalho, caracterizar físico-quimicamente frutos de novas variedades de laranjas tipo Bahia, buscando opções que apresentem boas características, como precocidade de produção, ausência de sementes, boa coloração e características organolépticas aceitas pelo mercado. Dessa forma, foram avaliados frutos de cinco novas variedades de laranja doce, tipo Bahia: Bahia Valente (CN 28), Golden Nugget Navel (CN 41), Robertson Navel (CN 39), Washington Navel (CV 27) e Washington Navel I (CN 34), durante duas safras (2012/2013 e 2013/2014), quantificando-se as seguintes variáveis físicoquímicas: massa, coloração da casca, rendimento de suco, acidez, sólidos solúveis e ratio. As variedades em estudo foram comparadas à variedade comercial Bahia Cabula (CV 25). As novas variedades produziram frutos com padrões requeridos pelo mercado consumidor, com massa do fruto adequada para venda in natura, bom rendimento de suco e maturação precoce (março), que proporciona a colheita na entressafra da Bahia Cabula no mercado. Dessa forma conclui-se que há variedades tipo Bahia, com qualidade físico-química aceitável e de ciclo precoce.(AU)
Assuntos
Citrus sinensis/química , Citrus sinensis/crescimento & desenvolvimento , Fenômenos QuímicosRESUMO
O Brasil é o maior produtor de laranja do mundo. Cultura rica em óleos essenciais de ampla aplicação, como no controle de pragas e patógenos, dentre eles os fitonematoides, causadores de prejuízos relevantes à agricultura. Assim, o objetivo do trabalho foi avaliar a porcentagem de eclosão de juvenis de M. javanica submetidos à diferentes concentrações de óleos essenciais de duas variedades de laranja, Pêra Rio e Folha Murcha, em condições in vitro. Os óleos essenciais foram extraídos das variedades de laranja (Citrus sinensis) Pêra Rio e Folha Murcha, pela técnica de hidrodestilação. O experimento foi instalado em arranjo fatorial 2X8, DIC, sendo oito concentrações (0, 25, 50, 100, 200, 300, 400 e 500 µg mL-1) e dois tipos de OE, avaliados em três períodos (4 e 16 dias). Em cada unidade experimental, tubos de ensaio 10x75 mm, adicionou-se 1 mL de suspensão de nematoides contendo 50 ovos e 1 mL de emulsão para cada concentração, avaliando-se a porcentagem de juvenis eclodidos. As concentrações dos óleos essenciais das variedades influenciaram (p≤0,05) na porcentagem de eclosão de juvenis de M. javanica, em todos os períodos avaliados. Para a maioria das concentrações, aos quatro e 16 dias, o óleo essencial da var. Pêra Rio foi mais eficiente na redução da eclosão, quando comparado a var. Folha Murcha.(AU)
Brazil is the largest producer of oranges in the world. This crop is rich in essential oils which are used in a wide range of applications, such as controlling pests and pathogens. Phytonematodes are among such pests, and are responsible for causing harmful damages to agriculture. Thus, the purpose of this study was to evaluate the percentage of hatching of M. javanica juveniles submitted to different concentrations of orange essential oil under in-vitro conditions. Oils were extracted from two varieties of orange (Citrus sinensis) popularly known in Brazil as Pera Rio and Folha Murcha, using the hydro-distillation technique. The experiment was carried out in a 2X8 factorial arrangement, at eight concentrations (0, 25, 50, 100, 200, 300, 400 and 500 µg mL-1) and two types of essential oils, evaluated in two periods (4 and 16 days). In each experimental unit, 10x75-mm test tubes received 1-mL nematode suspension containing 50 eggs and 1-mL of emulsion added for each concentration. Then, the percentage of hatched juveniles was evaluated. The concentration of essential oils from the varieties influenced (p≤0.05) the percentage of hatching of M. javanica juveniles in all evaluated periods. For most concentrations, at 4 and 16 days, the Pera Rio variety was more efficient at reducing hatching when compared to the Folha Murcha variety.(AU)
Brasil es el mayor productor de naranja del mundo. Cultura rica en aceites esenciales de amplia aplicación, como en el control de plagas y patógenos, entre ellos los fitonematodos, causantes de perjuicios relevantes a la agricultura. Así, el objetivo del trabajo fue evaluar el porcentaje de eclosión de juveniles de M. javanica sometidos a diferentes concentraciones de aceites esenciales de dos variedades de naranja, Pera Río y Hoja Mustia, en condiciones in vitro. Los aceites esenciales fueron extraídos de las variedades de naranja (Citrus sinensis) Pera Río y Hoja Mustia, por la técnica de hidrodestilación. El experimento fue instalado en un arreglo factorial 2x8, DIC, siendo ocho concentraciones (0, 25, 50, 100, 200, 300, 400 y 500 µg mL-1) y dos tipos de OE, evaluados en tres períodos (4 y 16 días). En cada unidad experimental, tubos de ensayo 10x75 mm, se añadieron 1 mL de suspensión de nematodos conteniendo 50 huevos y 1 mL de emulsión para cada concentración, evaluando el porcentaje de juveniles eclosionados. Las concentraciones de los aceites esenciales de las variedades influenciaron (p≤0,05) en el porcentaje de eclosión de juveniles de M. javanica, en todos los períodos evaluados. Para la mayoría de las concentraciones, a los cuatro y 16 días, el aceite esencial de la var. Pera Río fue más eficiente en la reducción de la eclosión, cuando comparado a var. Hoja Mustia.(AU)
Assuntos
Citrus sinensis/crescimento & desenvolvimento , Citrus sinensis/química , Óleos Voláteis/análise , Citrus sinensis/parasitologia , TylenchoideaRESUMO
O Brasil é o maior produtor de laranja do mundo. Cultura rica em óleos essenciais de ampla aplicação, como no controle de pragas e patógenos, dentre eles os fitonematoides, causadores de prejuízos relevantes à agricultura. Assim, o objetivo do trabalho foi avaliar a porcentagem de eclosão de juvenis de M. javanica submetidos à diferentes concentrações de óleos essenciais de duas variedades de laranja, Pêra Rio e Folha Murcha, em condições in vitro. Os óleos essenciais foram extraídos das variedades de laranja (Citrus sinensis) Pêra Rio e Folha Murcha, pela técnica de hidrodestilação. O experimento foi instalado em arranjo fatorial 2X8, DIC, sendo oito concentrações (0, 25, 50, 100, 200, 300, 400 e 500 µg mL-1) e dois tipos de OE, avaliados em três períodos (4 e 16 dias). Em cada unidade experimental, tubos de ensaio 10x75 mm, adicionou-se 1 mL de suspensão de nematoides contendo 50 ovos e 1 mL de emulsão para cada concentração, avaliando-se a porcentagem de juvenis eclodidos. As concentrações dos óleos essenciais das variedades influenciaram (p≤0,05) na porcentagem de eclosão de juvenis de M. javanica, em todos os períodos avaliados. Para a maioria das concentrações, aos quatro e 16 dias, o óleo essencial da var. Pêra Rio foi mais eficiente na redução da eclosão, quando comparado a var. Folha Murcha.(AU)
Brazil is the largest producer of oranges in the world. This crop is rich in essential oils which are used in a wide range of applications, such as controlling pests and pathogens. Phytonematodes are among such pests, and are responsible for causing harmful damages to agriculture. Thus, the purpose of this study was to evaluate the percentage of hatching of M. javanica juveniles submitted to different concentrations of orange essential oil under in-vitro conditions. Oils were extracted from two varieties of orange (Citrus sinensis) popularly known in Brazil as Pera Rio and Folha Murcha, using the hydro-distillation technique. The experiment was carried out in a 2X8 factorial arrangement, at eight concentrations (0, 25, 50, 100, 200, 300, 400 and 500 µg mL-1) and two types of essential oils, evaluated in two periods (4 and 16 days). In each experimental unit, 10x75-mm test tubes received 1-mL nematode suspension containing 50 eggs and 1-mL of emulsion added for each concentration. Then, the percentage of hatched juveniles was evaluated. The concentration of essential oils from the varieties influenced (p≤0.05) the percentage of hatching of M. javanica juveniles in all evaluated periods. For most concentrations, at 4 and 16 days, the Pera Rio variety was more efficient at reducing hatching when compared to the Folha Murcha variety.(AU)
Brasil es el mayor productor de naranja del mundo. Cultura rica en aceites esenciales de amplia aplicación, como en el control de plagas y patógenos, entre ellos los fitonematodos, causantes de perjuicios relevantes a la agricultura. Así, el objetivo del trabajo fue evaluar el porcentaje de eclosión de juveniles de M. javanica sometidos a diferentes concentraciones de aceites esenciales de dos variedades de naranja, Pera Río y Hoja Mustia, en condiciones in vitro. Los aceites esenciales fueron extraídos de las variedades de naranja (Citrus sinensis) Pera Río y Hoja Mustia, por la técnica de hidrodestilación. El experimento fue instalado en un arreglo factorial 2x8, DIC, siendo ocho concentraciones (0, 25, 50, 100, 200, 300, 400 y 500 µg mL-1) y dos tipos de OE, evaluados en tres períodos (4 y 16 días). En cada unidad experimental, tubos de ensayo 10x75 mm, se añadieron 1 mL de suspensión de nematodos conteniendo 50 huevos y 1 mL de emulsión para cada concentración, evaluando el porcentaje de juveniles eclosionados. Las concentraciones de los aceites esenciales de las variedades influenciaron (p≤0,05) en el porcentaje de eclosión de juveniles de M. javanica, en todos los períodos evaluados. Para la mayoría de las concentraciones, a los cuatro y 16 días, el aceite esencial de la var. Pera Río fue más eficiente en la reducción de la eclosión, cuando comparado a var. Hoja Mustia.(AU)
Assuntos
Citrus sinensis/química , Citrus sinensis/crescimento & desenvolvimento , Citrus sinensis/parasitologia , Óleos Voláteis/análise , TylenchoideaRESUMO
The cultivation of new types of oranges can be a good alternative for citrus growers because there is a growing domestic market and good export prospects. Due to these expectations, it is essential to search for new cultivars for use in the fresh fruit industry. Therefore, the aim of this work was to physicochemically characterize the fruits of new cultivars of Navel oranges, seeking alternatives with good characteristics, such as earliness, lack of seeds, good color and organoleptic characteristics desired by the consumer market. The fruits of five new cultivars of Navel orange were evaluated, namely, Bahia Valente (CN 28), Golden Nugget Navel (CN 41), Robertson Navel (CN 39), Washington Navel (CV 27) and Washington Navel I (CN 34), during two harvest seasons (2012/2013 and 2013/2014). The following physicochemical variables were quantified: mass, peel color, juice yield, acidity, soluble solids and ratio. The cultivars studied were compared to the commercial cultivar Bahia Cabula (CV 25). The new cultivars produced fruit with standards that met consumer expectations, with fruit mass suitable for sale of the fresh fruit, good yield juice and early maturation (March), which enables harvesting Bahia Cabula in the off-season period. Thus, it is concluded that there are navel orange cultivars with acceptable physicochemical qualities and early maturation.
O plantio de novos tipos de laranjas pode ser boa alternativa aos citricultores, pois há um mercado interno crescente e boas perspectivas de exportação. Em decorrência dessas expectativas torna-se primordial buscar novas variedades para o segmento de frutas frescas. Portanto, objetivou-se, com este trabalho, caracterizar físico-quimicamente frutos de novas variedades de laranjas tipo Bahia, buscando opções que apresentem boas características, como precocidade de produção, ausência de sementes, boa coloração e características organolépticas aceitas pelo mercado. Dessa forma, foram avaliados frutos de cinco novas variedades de laranja doce, tipo Bahia: Bahia Valente (CN 28), Golden Nugget Navel (CN 41), Robertson Navel (CN 39), Washington Navel (CV 27) e Washington Navel I (CN 34), durante duas safras (2012/2013 e 2013/2014), quantificando-se as seguintes variáveis físicoquímicas: massa, coloração da casca, rendimento de suco, acidez, sólidos solúveis e ratio. As variedades em estudo foram comparadas à variedade comercial Bahia Cabula (CV 25). As novas variedades produziram frutos com padrões requeridos pelo mercado consumidor, com massa do fruto adequada para venda in natura, bom rendimento de suco e maturação precoce (março), que proporciona a colheita na entressafra da Bahia Cabula no mercado. Dessa forma conclui-se que há variedades tipo Bahia, com qualidade físico-química aceitável e de ciclo precoce.
Assuntos
Citrus sinensis/crescimento & desenvolvimento , Citrus sinensis/química , Fenômenos QuímicosRESUMO
The carambola fruit fly, Bactrocera carambolae, is a tephritid native to Asia that has invaded South America through small-scale trade of fruits from Indonesia. The economic losses associated with biological invasions of other fruit flies around the world and the polyphagous behaviour of B. carambolae have prompted much concern among government agencies and farmers with the potential spread of this pest. Here, ecological niche models were employed to identify suitable environments available to B. carambolae in a global scale and assess the extent of the fruit acreage that may be at risk of attack in Brazil. Overall, 30 MaxEnt models built with different combinations of environmental predictors and settings were evaluated for predicting the potential distribution of the carambola fruit fly. The best model was selected based on threshold-independent and threshold-dependent metrics. Climatically suitable areas were identified in tropical and subtropical regions of Central and South America, Sub-Saharan Africa, west and east coast of India and northern Australia. The suitability map of B. carambola was intersected against maps of fruit acreage in Brazil. The acreage under potential risk of attack varied widely among fruit species, which is expected because the production areas are concentrated in different regions of the country. The production of cashew is the one that is at higher risk, with almost 90% of its acreage within the suitable range of B. carambolae, followed by papaya (78%), tangerine (51%), guava (38%), lemon (30%), orange (29%), mango (24%) and avocado (20%). This study provides an important contribution to the knowledge of the ecology of B. carambolae, and the information generated here can be used by government agencies as a decision-making tool to prevent the carambola fruit fly spread across the world.
Assuntos
Distribuição Animal/fisiologia , Frutas/crescimento & desenvolvimento , Frutas/parasitologia , Tephritidae/fisiologia , Agricultura/economia , Agricultura/métodos , Anacardium/crescimento & desenvolvimento , Anacardium/parasitologia , Animais , Brasil , Carica/crescimento & desenvolvimento , Carica/parasitologia , Citrus sinensis/crescimento & desenvolvimento , Citrus sinensis/parasitologia , Clima , Ecossistema , Geografia , Interações Hospedeiro-Parasita , Mangifera/crescimento & desenvolvimento , Mangifera/parasitologia , Modelos Teóricos , Persea/crescimento & desenvolvimento , Persea/parasitologia , Dinâmica Populacional , Psidium/crescimento & desenvolvimento , Psidium/parasitologia , Fatores de RiscoRESUMO
BACKGROUND: Chemical control is the method most used for management of Diaphorina citri, the vector of the phloem-limited bacteria associated with citrus huanglongbing (HLB) disease. The objectives of this study were to determine the influence of soil-drench applications of neonicotinoids (thiamethoxam and imidacloprid) on the probing behaviour of D. citri on citrus nursery trees, using the electrical penetration graph (EPG) technique, and to measure the D. citri settling behaviour after probing on citrus nursery trees that had received these neonicotinoid treatments. RESULTS: The drench applications of neonicotinoids on citrus nursery trees disrupt D. citri probing, mainly for EPG variables related to phloem sap ingestion, with a significant reduction (≈90%) in the duration of this activity compared with untreated plants in all assessment periods (15, 35 and 90 days after application). Moreover, both insecticides have a repellent effect on D. citri, resulting in significant dispersal of psyllids from treated plants. CONCLUSIONS: This study clearly demonstrates the interference of soil-applied neonicotinoids on the feeding and settling behaviour of D. citri on citrus nursery trees, mainly during the phloem ingestion phase. These findings reinforce the recommendation of drench application of neonicotinoids before planting nursery trees as a useful strategy for HLB management. © 2015 Society of Chemical Industry.
Assuntos
Hemípteros , Imidazóis , Controle de Insetos , Inseticidas , Nitrocompostos , Oxazinas , Tiazóis , Animais , Citrus sinensis/crescimento & desenvolvimento , Comportamento Alimentar/efeitos dos fármacos , Feminino , Neonicotinoides , Tiametoxam , Árvores/crescimento & desenvolvimentoRESUMO
Late Embryogenesis Abundant (LEA) proteins are an ubiquitous group of polypeptides that were first described to accumulate during plant seed dehydration, at the later stages of embryogenesis. Since then they have also been recorded in vegetative plant tissues experiencing water limitation and in anhydrobiotic bacteria and invertebrates and, thereby, correlated with the acquisition of desiccation tolerance. This study provides the first comprehensive study about the LEA gene family in sweet orange (Citrus sinensis L. Osb.), the most important and widely grown fruit crop around the world. A surprisingly high number (72) of genes encoding C. sinensis LEAs (CsLEAs) were identified and classified into seven groups (LEA_1, LEA_2, LEA_3 and LEA_4, LEA_5, DEHYDRIN and SMP) based on their predicted amino acid sequences and also on their phylogenetic relationships with the complete set of Arabidopsis thaliana LEA proteins (AtLEAs). Approximately 60% of the CsLEAs identified in this study belongs to the unusual LEA_2 group of more hydrophobic LEA proteins, while the other LEA groups contained a relatively small number of members typically hydrophilic. A correlation between gene structure and motif composition was observed within each LEA group. Investigation of their chromosomal localizations revealed that the CsLEAs were non-randomly distributed across all nine chromosomes and that 33% of all CsLEAs are segmentally or tandemly duplicated genes. Analysis of the upstream sequences required for transcription revealed the presence of various stress-responsive cis-acting regulatory elements in the promoter regions of CsLEAs, including ABRE, DRE/CRT, MYBS and LTRE. Expression analysis using both RNA-seq data and quantitative real-time RT-PCR (qPCR) revealed that the CsLEA genes are widely expressed in various tissues, and that many genes containing the ABRE promoter sequence are induced by drought, salt and PEG. These results provide a useful reference for further exploration of the CsLEAs functions and applications on crop improvement.
Assuntos
Citrus sinensis/crescimento & desenvolvimento , Citrus sinensis/genética , Regulação da Expressão Gênica de Plantas , Proteínas de Plantas/genética , Estresse Fisiológico , Cromossomos de Plantas , Citrus sinensis/embriologia , Genoma de Planta , FilogeniaRESUMO
O objetivo foi verificar a influência do sistema de cultivo, orgânico e convencional, sobre as características físicas e químicas e sobre a aceitação pelo consumidor de laranjas 'Valência' (Citrus sinensis (L.) Osb.). Os pomares foram instalados no município de Montenegro, em julho de 2001, em espaçamento de 2,5mx5,0m, cada um possuindo uma área de 0,25ha. As avaliações foram realizadas a partir de amostras de frutos colhidas em setembro e outubro de 2011 e em outubro de 2012. Os parâmetros físicos e químicos analisados nos frutos foram: teor de suco (TS), teor de sólidos solúveis (SS), acidez titulável (AT), relação SS/AT e índice de cor da casca.A avaliação da aceitação das laranjas foi realizada com avaliadores não treinados, e utilizando escala hedônica de nove pontos, que expressam o grau de gostar ou desgostar do produto. O delineamento experimental foi completamente casualizado. Os frutos apresentaram parâmetros de qualidade adequados aos padrões internacionais e não diferiram entre si quanto as suas características físicas e químicas na maioria dos atributos avaliados. A aceitação foi satisfatória em todos os atributos avaliados (todos superiores a 70%). As diferenças observadas nos atributos físicos e químicos não foram percebidas pelos avaliadores, não havendo, portanto, distinção na aceitação dos frutos pelo consumidor entre os sistemas de cultivo.(AU)
The objective of the research was to investigate the influence of cultivating systems (organic and conventional) on physical and chemical attributes, and consumer acceptance of 'Valencia' oranges (Citrus sinensis (L.) Osb.). The orchards were field planted in Montenegro, Brazil, in July 2001. Plants are spaced 2.5m in the row by 5.0m between rows, totaling 0.25ha each orchard. Evaluations were made using fruit samples collected in September and October of 2011, and October of 2012. The physical and chemical attributes evaluated were: juice contents (TS), soluble solids (SS), titratable acidity (AT), ratio SS/AT and color index in the peel (ICC). The oranges' consumer acceptance was determined by untrained evaluators using a nine-point hedonic scale, where the degree in which they'like' or 'dislike' the product is expressed. The experimental design was completely randomized. As results, oranges showed parameters of quality accordingly to international standards. The physical and chemical attributes were not different between conventional and organic systems for most attributes evaluated. Consumer acceptance was satisfactory in all attributes evaluated (all above 70%). The differences observed on the physical and chemical attributes were not perceived by the evaluators; therefore, there is no distinction on the acceptability of the fruits by consumers despite of the cultivation system.(AU)
Assuntos
Citrus sinensis/crescimento & desenvolvimento , Frutas/crescimento & desenvolvimento , Agricultura Orgânica , Alimentos Orgânicos , 24444RESUMO
Intercropping could efficiently prevent soil nutrient losses caused by extensive agriculture. The present study aimed to assess the effect of green manure on the nutritional status of orange trees cultivar 'Pera' (Citrus sinensis (L.) Osbeck). The plants were grafted on 'Cravo' lime trees and were then planted in a 7x4m space. Four different treatments corresponding to the evaluated green manures were employed: jack bean (JB) (Canavalia ensiformis DC), lablab (LL) (Dolichos lablab L.), pigeon pea (PP) (Cajanus cajan L. Millsp), and Brachiaria (BQ) (Brachiaria brizantha Hochst ex A. Rich. Stapf) as control. The experimental design was in randomized blocks, in split-plot time, with six replicates, with four treatments (green manures) and two plants per evaluation. The nutritional status was assessed by using the DRIS method (Diagnosis and Recommendation Integrated System); the yield and the macro and micronutrient levels contained in green manures and in the control was also determined. The nutritional diagnosis indicated that, in the two years of experiment, plants treated with green manure showed better nutritional balance index compared to Brachiaria. This suggests that, over time, green manure can lead to better nutritional balance. Pigeon pea treatment showed the highest yields, compared to control, in the two evaluated crop cycles (2004/05 and 2005/06).(AU)
O manejo de culturas intercalares poderia prevenir eficientemente as perdas de nutrientes do solo, causadas pelo cultivo extensivo. O trabalho teve como objetivo avaliar o efeito da utilização de adubos verdes no estado nutricional de plantas de laranjeira 'Pêra' (Citrus sinensis (L.) Osbeck). O solo da área de cultivo é denominado Neossolo Quartzarênico. As plantas estavam enxertadas em limoeiro 'Cravo' e foram plantadas num espaçamento de sete por quatro metros. Foram empregados quatro tratamentos correspondentes aos adubos verdes avaliados, sendo eles: feijão de porco (FP) (Canavalia ensiformis DC), labe-labe (LL) (Dolichus lablab L.), feijão guandu anão (GA) (Cajanus cajan L. Millsp) e braquiária (BQ) (Brachiaria brizantha Hochst ex A. Rich. Stapf). Conduziu-se o experimento em delineamento de blocos casualizados em esquema de parcelas subdivididas no tempo, com seis repetições, quatro tratamentos (adubos verdes) e duas plantas úteis para as avaliações. Avaliou-se o estado nutricional pelo método DRIS (Sistema Integrado de Diagnose e Recomendação), bem como a produção e o teor de macro e micronutrientes contidos nos adubos verdes e na testemunha. O diagnóstico nutricional demonstrou que, nos dois anos de experimentação, houve um melhor índice de balanço nutricional para os adubos verdes, quando comparados com a braquiária (testemunha). Esta constatação permite inferir sobre a disponibilidade de, ao longo do tempo, os adubos verdes permitirem um melhor equilíbrio nutricional para as plantas. O tratamento com feijão de porco apresentou as maiores produções, quando comparado com a testemunha, nos dois ciclos agrícolas de avaliação (2004/05 e 2005/06).(AU)
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Citrus sinensis/crescimento & desenvolvimento , Nutrientes/análiseRESUMO
BACKGROUND: The uptake of sulphur-containing compounds plays a pivotal role in the physiology of bacteria that live in aerobic soils where organosulfur compounds such as sulphonates and sulphate esters represent more than 95% of the available sulphur. Until now, no information has been available on the uptake of sulphonates by bacterial plant pathogens, particularly those of the Xanthomonas genus, which encompasses several pathogenic species. In the present study, we characterised the alkanesulphonate uptake system (Ssu) of Xanthomonas axonopodis pv. citri 306 strain (X. citri), the etiological agent of citrus canker. METHODOLOGY/PRINCIPAL FINDINGS: A single operon-like gene cluster (ssuEDACB) that encodes both the sulphur uptake system and enzymes involved in desulphurisation was detected in the genomes of X. citri and of the closely related species. We characterised X. citri SsuA protein, a periplasmic alkanesulphonate-binding protein that, together with SsuC and SsuB, defines the alkanesulphonate uptake system. The crystal structure of SsuA bound to MOPS, MES and HEPES, which is herein described for the first time, provides evidence for the importance of a conserved dipole in sulphate group coordination, identifies specific amino acids interacting with the sulphate group and shows the presence of a rather large binding pocket that explains the rather wide range of molecules recognised by the protein. Isolation of an isogenic ssuA-knockout derivative of the X. citri 306 strain showed that disruption of alkanesulphonate uptake affects both xanthan gum production and generation of canker lesions in sweet orange leaves. CONCLUSIONS/SIGNIFICANCE: The present study unravels unique structural and functional features of the X. citri SsuA protein and provides the first experimental evidence that an ABC uptake system affects the virulence of this phytopathogen.
Assuntos
Alcanossulfonatos/química , Proteínas de Bactérias/genética , Proteínas de Transporte/genética , Citrus sinensis/microbiologia , Xanthomonas/patogenicidade , Alcanossulfonatos/metabolismo , Sequência de Aminoácidos , Proteínas de Bactérias/química , Proteínas de Bactérias/fisiologia , Sítios de Ligação , Proteínas de Transporte/química , Proteínas de Transporte/fisiologia , Citrus sinensis/crescimento & desenvolvimento , Citrus sinensis/metabolismo , Modelos Moleculares , Dados de Sequência Molecular , Doenças das Plantas/microbiologia , Polissacarídeos Bacterianos/metabolismo , Alinhamento de Sequência , Virulência , Difração de Raios X , Xanthomonas/genética , Xanthomonas/metabolismoRESUMO
BACKGROUND: Leprosis is one of the most serious citrus plant diseases. Leprosis-affected plants, especially sweet orange [Citrus sinensis (L.) Osbeck], which is the most widely cultivated citrus fruit worldwide, show reduced photosynthetic capacity and severe defoliation. The aim was to evaluate the relationship between the Brevipalpus phoenicis (Geijskes) vector mite and citrus leprosis disease in Pera sweet orange plants grafted on different rootstocks. Data were analysed using numerical classification and conventional statistical analysis (ANOVA). RESULTS: Both viruliferous and non-viruliferous B. phoenicis populations increased in number on plants maintained at low soil water content. Among the evaluated rootstocks, Sunki mandarin proved least favourable for mite population increase. Furthermore, the viruliferous mite population increased more rapidly than the non-viruliferous mite population. CONCLUSION: The Cleopatra rootstock showed low variability in leaf nitrogen content, low mite number and low leprosis severity, thereby producing the most favourable results. Under appropriate moisture conditions, the Sunki rootstock produced the best results, showing the least severe leprosis. Rangpur lime rootstock grown in soil with varying water content showed the greatest variation in foliar nitrogen content, mite number and severity of leprosis and is considered to be the most difficult rootstock to manage.
Assuntos
Citrus sinensis/crescimento & desenvolvimento , Citrus sinensis/genética , Ácaros/fisiologia , Doenças das Plantas/etiologia , Agricultura , Animais , Brasil , Cadeia Alimentar , Análise Multivariada , Folhas de Planta/genética , Folhas de Planta/crescimento & desenvolvimento , Raízes de Plantas/genética , Raízes de Plantas/crescimento & desenvolvimento , Distribuição AleatóriaRESUMO
En este trabajo se evaluó el efecto de diferentes cepas de levadura (Montrachet, K1-V1116, EC-1118, 71B-1122 y IVC-GRE ®) sobre los atributos sensoriales del vino de naranja. Estos atributos fueron medidos utilizando la escala modificada de UC Davis. En una prueba de ordenamiento para determinar el mejor tratamiento de clarificación se determinó que la gelatina por sí sola no causa efecto sobre el atributo apariencia general, la combinación de la gelatina y la microfiltración tienen un efecto positivo sobre la apariencia del vino de naranja. Los cinco vinos tratados con diferentes levaduras presentaron diferencias significativas sobre la puntuación total, acidez total, sabor y calidad en general. En términos del efecto de las levaduras, la evaluación sensorial realizada a los vinos mostró que el de naranja con la levadura K1-V1116 fue el que sobresalió en términos de puntuación en los promedios de casi todos los atributos analizados por el panel sensorial.
In this Wort was evaluated the effect of different types of strains of yeast (Montrachet, K1-V1116, EC-1118, 71B-1122 y IVC-GRE) over the sensorial attributes of orange wines were also studied. These attributes were measured in a modified scale of UC Davis. By using an order test in order to know the best cleared treatment, it was determined that gelatin by itself does not cause any effect over the general quality attribute, but the combination of gelatin and microfiltration, cause a positive effect over the orange wine appearance. The five wines treated with different yeasts presented significant differences on individual scores, total acidy, flavor and general quality of the UC Davis scale. The sensorial evaluation of wines showed that the yeast K1-V1116 produced the best rated orange wine. This wine was significantly different over many attributes when compared with the other wines evaluated by the sensorial panel.
Assuntos
Citrus sinensis/classificação , Citrus sinensis/crescimento & desenvolvimento , Citrus sinensis/fisiologia , Citrus sinensis/genética , Citrus sinensis/imunologia , Citrus sinensis/metabolismo , Citrus sinensis/microbiologia , Citrus sinensis/química , Citrus sinensis/ultraestrutura , Fermento Seco/isolamento & purificação , Fermento Seco/análise , Fermento Seco/farmacologia , Fermento Seco/genética , Fermento Seco/imunologia , Fermento Seco/metabolismoRESUMO
BACKGROUND: Three categories of seed storage behavior are generally recognized among plant species: orthodox, intermediate and recalcitrant. Intermediate seeds cannot be stored in liquid nitrogen (LN) without a previous partial dehydration process. The water content (WC) of the seeds at the moment of immersion in LN must be regarded as the most critical factor in cryopreservation. The purpose of this study was to investigate the basis of the optimal hydration status for cryopreservation of Citrus seeds: C. sinensis (sweet orange), C. paradisi (grapefruit), C. reticulata (mandarin) in LN. RESULTS: To study the tolerance to dehydration and LN exposure, seeds were desiccated by equilibration at relative humidities between 11 and 95%. Sorption isotherms were determined and modeled; lipid content of the seeds was measured. Seed desiccation sensitivity was quantified by the quantal response model. Differential scanning calorimetry (DSC) thermograms were determined on cotyledon tissue at different moisture contents to measure ice melting enthalpies and unfrozen WC. Samples of total seed lipid extract were also analyzed by DSC to identify lipid transitions in the thermograms. CONCLUSIONS: The limit of hydration for LN Citrus seeds treatment corresponded to the unfrozen WC in the tissue, confirming that seed survival strictly depended on avoidance of intracellular ice formation.
Assuntos
Agricultura/métodos , Citrus , Criopreservação , Dessecação , Sementes , Água/análise , Varredura Diferencial de Calorimetria , Citrus/química , Citrus/crescimento & desenvolvimento , Citrus paradisi/química , Citrus paradisi/crescimento & desenvolvimento , Citrus sinensis/química , Citrus sinensis/crescimento & desenvolvimento , Cotilédone/química , Cotilédone/crescimento & desenvolvimento , Difusão , Germinação , Lipídeos/análise , Lipídeos/química , Modelos Biológicos , Transição de Fase , Extratos Vegetais/química , Sementes/química , Sementes/crescimento & desenvolvimento , Especificidade da EspécieRESUMO
Four citrus fruit varieties cultivated in Brazil (two kinds of sweet orange and two kinds of tangerine) were analyzed for physicochemical characteristics contents of total phenolics, total carotenoids and ascorbic acid, and antioxidant activities. The antioxidant activities of aqueous, methanolic, and acetone extracts of the citrus fruit juices were assessed on the basis of their ability to scavenge 1,1-diphenyl-2-picrylhydrazyl (DPPHâ¢). The cravo tangerine has the highest content of citric acid, while the pera orange is richest in ascorbic acid. The lima orange has the highest total phenolic contents, and the ponkan the highest total carotenoids. The antioxidant activities, expressed as the concentration of antioxidant able to scavenge 50% of the initial DPPH⢠(EC50), ranged from 139.1 ± 27.3 to 182.2 ± 28.8 g extract/l for juice of orange varieties and 186.3 ± 29.6 to 275.5 ± 3.3g extract/l for juice of tangerine citrus varieties. In methanolic extracts the EC50 ranged from 192.5 ± 43.1 to 267.4 ± 41.4 g extract/l for orange varieties and from 225.2 ± 69.8 to 336.3 ± 27.2 g extract/l for tangerine varieties. For EC50 values of acetone fractions, there were no statistically significant differences between the different varieties. For every citrus fruit in the present study, the radical scavenging capacity was higher in the aqueous than in the methanolic or acetone fractions.