RESUMO

Mizuna (Brassica rapa var. japonica), a member of family Brassicaceae, is a leafy vegetable having phenolic and other compounds beneficial to human health, such as natural antioxidants (Khanam et al. 2012). In October 2020, a field of mizuna (variety: Early) on Oahu island was observed having 20-30% diseased plants. Four randomly selected infected mizuna plants, showing the symptoms of wilt and stem rot (Figure 1A-D), were collected and isolations were made to determine the pathogen. Small sections of infected stems were cut, surface sterilized with 0.6% sodium hypochlorite solution for 30 sec, followed by three consecutive rinses in distilled water. The tissues were macerated in a sterile 1.5 ml centrifuge tube containing 100 µl sterile water-macerated tissues were streaked onto crystal violet pectate medium (CVP) (Hélias et al. 2011) and incubated at 26 ± 2°C for 48 h. Isolated bacterial colonies that formed pits on the CVP plates were re-streaked onto dextrose peptone agar: Peptone (10 g/L), Dextrose (5 g/L) and Agar (17 g/L) (DPA-without tetrazolium chloride; Norman and Alvarez 1989) to obtain purified colonies for DNA isolation using DNeasy Blood and Tissue Kit (Qiagen, Germantown, MA). The two housekeeping genes (dnaA and gapA) were amplified and sequenced following the protocols used by Dobhal et al. (2020) and Boluk et al. (2020), for identity confirmation and phylogenetic analysis. Cleaned PCR products were sent to the GENEWIZ facility (Genewiz, La Jolla, CA) for sequencing of sense and antisense strands. The obtained sequences were aligned, manually edited, and consensus sequences were analyzed with BLASTn using the NCBI GenBank nucleotide and genome databases for identity confirmation. The BLASTn results demonstrated 100% query coverage of all four strains (PL248-PL251); and showed 100% identity of PL248 and PL249, and 99% identity of PL250 and PL251 with Pectobacterium brasiliense. All the sequences were submitted to the NCBI GenBank database under the following accession numbers: dnaA gene MW560271 - MW560274 (PL248 - PL251); and gapA gene MW560275 - MW560278 (PL248 - PL251). Pathogenicity was assessed by artificially inoculating 100 µl bacterial suspension of each strain (PL248 - 1.12x 108 CFU/ml; PL249 - 1.32x 108 CFU/ml; PL 250 - 1.2x 108 CFU/ml and PL251 - 1.15x 108 CFU/ml) onto four-week-old mizuna (variety: Leafy Asian Greens) plants in three replicates, using sterile pipette tips, which was stabbed into stem halfway and wrapped with parafilm. The inoculated plants were well maintained under controlled greenhouse conditions. As negative controls, three plants were inoculated with 100 µl distilled water. Soft rot and wilt symptoms (Figure 1E-H) were observed 24 hours post inoculation. No symptoms were observed on control plants (Figure 1F). All four strains were re-isolated from the inoculated plants and confirmed as P. brasiliense based on resequencing of the dnaA region and 100% homology with the sequences of original strain. In the phylogenetic tree (Figure 2), based on two housekeeping genes (dnaA and gapA), the bacterial strains from mizuna grouped with other P. brasiliense retrieved from the NCBI GenBank database. To our knowledge, this is the first report of P. brasiliense infecting mizuna plants in Hawaii or in the USA and is important because this species is one of the most aggressive pectolytic pathogens in the genus Pectobacterium. Understanding the diversity of different pectolytic phytopathogens is essential to formulating risk mitigation strategies as P. brasiliense could potentially pose a threat to additional vegetable crops, especially the crucifers vegetables (Arizala et al. 2019; Klair et al, 2021).

RESUMO

Vegetable crop residues, such as sugarcane bagasse (SCB), despite their limited biodegradability, are potential materials for anaerobic processes because of their low cost, high availability, and sugar content. The difficulty of biodegrading this type of material is primarily related to its chemical composition and to the complex interactions between its compounds (cellulose, hemicelluloses, and lignin). Thus, the following supercritical and near critical carbon dioxide (CO2) pre-treatments were evaluated with and without the addition of sodium hydroxide (NaOH): (i) 40°C/70 kgf·cm-2; (ii) 60°C/200 kgf·cm-2; and (iii) 80°C/200 kgf·cm-2, aiming to enhance the anaerobic biodegradability of SCB. The methanogenic production of SCB increased in all cases in which the material was pre-treated, except the case in which NaOH was used together with a high temperature. The condition using CO2 at 60°C/200 kgf·cm-2 was highlighted with a lignin removal of 8.07% and an accumulated methane production of 0.6498 ± 0.014 LN (273.15K, 1.01325 × 105 Pa), 23.4% higher than the value obtained with the untreated material. This condition also showed the highest net energy at the energy balance that was calculated for comparison with the tested conditions. The results showed that pre-treatments with near critical and supercritical fluids have the potential to reduce structural obstacles of lignocellulosic materials and to enhance their anaerobic biodegradability.

Assuntos

RESUMO

We evaluated the effect of different soil water tensions on the production of broccoli cultivated in a protected environment under drip irrigation in order to establish criteria for the adequate management of irrigation. A completely randomized block design was used, comprising six treatments and four replicates. The treatments included six soil water tensions (15, 30, 45, 60, 75 and 90 kPa). Soil water tension was monitored with granular matrix sensors installed at depths of 0.2 m (decision sensors) and 0.4 m (seepage control sensors). Total and marketable fresh weight of broccoli heads, average diameter of marketable heads, height of marketable heads, and total and marketable yield were greatest when the soil water tension at a depth of 0.2 m was 15 kPa, at which the mean values of the evaluated variables were 0.84 kg, 0.76 kg, 20.5 cm, 11.7 cm; 26.5 t ha-1, and 23.7 t ha-1, respectively. Treatments did not significantly affect efficiency of water use or height of marketable heads.(AU)

Objetivou-se, avaliar o efeito de diferentes tensões de água no solo sobre a produção de brócolis, cultivado em ambiente protegido e irrigado por gotejamento, de forma a estabelecer critérios para o manejo adequado da irrigação. O experimento foi conduzido na Universidade Federal de Lavras, no período de Maio a Agosto de 2012. O delineamento experimental foi em blocos completos casualizados, com seis tratamentos e quatro repetições. Os tratamentos foram constituídos de seis tensões de água no solo (15, 30, 45, 60, 75 e 90 kPa). As tensões de água no solo foram monitoradas com base nos Sensores de Matriz Granular, watermark® instalados a 0,2 e a 0,4 m de profundidade. Dos resultados, concluiu-se que para a obtenção de maiores valores de massa fresca total e comercial, diâmetro médio da inflorescência, altura da inflorescência, produtividade total e comercial, as irrigações devem ser realizadas quando a tensão de água no solo estiver em torno de 15 kPa, à uma profundidade de 0,2 m. Os maiores valores atingidos foram de 0,84 kg; 0,76 kg; 20,5 cm; 11,5 cm; 26,47 t ha-1 e 23,71 t ha-1, respectivamente. A variação da tensão de água no solo não produziu efeito significativo na eficiência no uso de água e na altura da inflorescência comercial.(AU)

Assuntos

RESUMO

We evaluated the effect of different soil water tensions on the production of broccoli cultivated in a protected environment under drip irrigation in order to establish criteria for the adequate management of irrigation. A completely randomized block design was used, comprising six treatments and four replicates. The treatments included six soil water tensions (15, 30, 45, 60, 75 and 90 kPa). Soil water tension was monitored with granular matrix sensors installed at depths of 0.2 m (decision sensors) and 0.4 m (seepage control sensors). Total and marketable fresh weight of broccoli heads, average diameter of marketable heads, height of marketable heads, and total and marketable yield were greatest when the soil water tension at a depth of 0.2 m was 15 kPa, at which the mean values of the evaluated variables were 0.84 kg, 0.76 kg, 20.5 cm, 11.7 cm; 26.5 t ha-1, and 23.7 t ha-1, respectively. Treatments did not significantly affect efficiency of water use or height of marketable heads.

Objetivou-se, avaliar o efeito de diferentes tensões de água no solo sobre a produção de brócolis, cultivado em ambiente protegido e irrigado por gotejamento, de forma a estabelecer critérios para o manejo adequado da irrigação. O experimento foi conduzido na Universidade Federal de Lavras, no período de Maio a Agosto de 2012. O delineamento experimental foi em blocos completos casualizados, com seis tratamentos e quatro repetições. Os tratamentos foram constituídos de seis tensões de água no solo (15, 30, 45, 60, 75 e 90 kPa). As tensões de água no solo foram monitoradas com base nos Sensores de Matriz Granular, watermark® instalados a 0,2 e a 0,4 m de profundidade. Dos resultados, concluiu-se que para a obtenção de maiores valores de massa fresca total e comercial, diâmetro médio da inflorescência, altura da inflorescência, produtividade total e comercial, as irrigações devem ser realizadas quando a tensão de água no solo estiver em torno de 15 kPa, à uma profundidade de 0,2 m. Os maiores valores atingidos foram de 0,84 kg; 0,76 kg; 20,5 cm; 11,5 cm; 26,47 t ha-1 e 23,71 t ha-1, respectivamente. A variação da tensão de água no solo não produziu efeito significativo na eficiência no uso de água e na altura da inflorescência comercial.

Assuntos

RESUMO

Os atributos do solo são dinâmicos e estão sujeitos a alterações de acordo com o uso e manejo adotado, sendo sua determinação importante para melhor utilização agrícola dos solos. Desta forma, objetivou-se avaliar o comportamento de alguns atributos físicos (composição granulométrica, argila dispersa em água e grau de floculação) de um Latossolo Vermelho-Amarelo sobre diferentes usos, a saber: cultivado com duas espécies de leguminosas e sob vegetação espontânea, em área anteriormente cultivada com horticultura, por aproximadamente 10 anos, sob intensa mecanização agrícola e aplicação de corretivos e fertilizantes. O experimento foi instalado no delineamento em blocos casualizados, sendo conduzido em esquema fatorial 2 x 3, sendo duas profundidades (0 a 20 e 20 a 40 cm) e três coberturas vegetais (duas leguminosas e uma vegetação espontânea) com 4 repetições cada. Os dados das avaliações foram submetidos à análise de variância e as médias comparadas pelo teste de Tukey a 5% de probabilidade. Observou-se que a agitação lenta proporciona uma melhor dispersão física quando comparada com a agitação rápida, demonstrando maior acurácia e precisão. Os valores de argila dispersa em água são maiores na profundidade de 20-40 cm. O solo cultivado com mucuna preta, na profundidade de 20-40 cm, apresenta um maior valor de argila dispersa em água em relação às demais coberturas vegetais e o solo sob vegetação espontânea maior grau de floculação nesta profundidade.

Soil attributes are dynamic and are subject to change according to the use and management adopted, is important for determining its best use agricultural soil. Thus, it was aimed to evaluate some physical attributes (particle size, water dispersible clay and flocculation) of an Oxisol on different uses, namely: cultivated with two species of legumes and natural vegetation, in an area previously cultivated with vegetables, for about 10 years, under intense agricultural mechanization and application of lime and fertilizer. The experiment was conducted in a randomized block design, being conducted in factorial 2 x 3, two depths (0 to 20 and 20 to 40 cm) and three cover crops, with four replications. Data were submitted to analysis of variance and averages compared by Tukey test at 5% probability. It was Avaliação de alguns atributos... SANTOS, L. N. S. et al. Biosci. J., Uberlândia, v. 26, n. 6, p. 940-947, Nov./Dec. 2010 946 observed that the slow agitation provides better physical dispersion when compared with the fast agitation, showing greater accuracy and precision. The values of clay dispersed in water are larger at a depth of 20-40 cm. The soil under Mucuna pruriens L., in depth of 20-40 cm, has a higher value of water dispersible clay in water compared with to other cover crops and the soil under natural vegetation greater degree of flocculation this depth

Assuntos

RESUMO

The objective of this work was to analyze the effect of the application and absorption of ethylene, as well as the use of 1-methylcyclopropene (1-MCP) concerning the postharvest quality of ‘Teresópolis Gigante' cauliflower. According to the results, the greenest value of the head and of the leaf were got in treatments with application of 1-MCP and use of potassium permanganate. The least stem's firmness was got with the application of ethylene. Then the application of 1-MCP, as well as the use potassium permanganate promoted the maintenance of the green color of the head and of the leaf, as well as exogenous ethylene reduced the stem's firmness of the ‘Teresópolis Gigante' cauliflower.

O objetivo deste trabalho foi de avaliar o efeito da aplicação e absorção de etileno, assim como o uso de 1-metilciclopropeno (1-MCP) sobre a qualidade pós-colheita de couve-flor ‘Teresópolis Gigante'. Os tratamentos utilizados foram: armazenamento refrigerado, uso de saches de permanganato de potássio (80g), 1-MCP (1,0 e 0,5µl L-1) e aplicação de etileno (1,0µl L-1). De acordo com os resultados obtidos, a coloração mais verde da cabeça e das folhas foi obtida nos tratamentos com a aplicação de 1-MCP e uso de saches de permanganato de potássio. A menor firmeza da haste foi obtida com a aplicação de etileno. Conclui-se que a aplicação de 1-MCP, assim como o uso de saches de permanganato de potássio promovem a manutenção da cor verde da cabeça e das folhas, assim como o etileno exógeno reduz a firmeza da haste de couve-flor ‘Teresópolis Gigante'.

RESUMO

The objective of this work was to analyze the effect of the application and absorption of ethylene, as well as the use of 1-methylcyclopropene (1-MCP) concerning the postharvest quality of ‘Teresópolis Gigante' cauliflower. According to the results, the greenest value of the head and of the leaf were got in treatments with application of 1-MCP and use of potassium permanganate. The least stem's firmness was got with the application of ethylene. Then the application of 1-MCP, as well as the use potassium permanganate promoted the maintenance of the green color of the head and of the leaf, as well as exogenous ethylene reduced the stem's firmness of the ‘Teresópolis Gigante' cauliflower.

O objetivo deste trabalho foi de avaliar o efeito da aplicação e absorção de etileno, assim como o uso de 1-metilciclopropeno (1-MCP) sobre a qualidade pós-colheita de couve-flor ‘Teresópolis Gigante'. Os tratamentos utilizados foram: armazenamento refrigerado, uso de saches de permanganato de potássio (80g), 1-MCP (1,0 e 0,5µl L-1) e aplicação de etileno (1,0µl L-1). De acordo com os resultados obtidos, a coloração mais verde da cabeça e das folhas foi obtida nos tratamentos com a aplicação de 1-MCP e uso de saches de permanganato de potássio. A menor firmeza da haste foi obtida com a aplicação de etileno. Conclui-se que a aplicação de 1-MCP, assim como o uso de saches de permanganato de potássio promovem a manutenção da cor verde da cabeça e das folhas, assim como o etileno exógeno reduz a firmeza da haste de couve-flor ‘Teresópolis Gigante'.

RESUMO

Paulista gherkin is a new gherkin type obtained by crossing Cucumis anguria var. anguria x C. anguria var. longaculeatus. It differs from common gherkin in its fruits and leaves. Elite lines of Paulista gherkin present similar performance for total yield and fruit weight but some have distinctive characteristics, including fruit and leaf attributes. The combination of these characteristics through production of Paulista gherkin hybrids could be an alternative for fruit quality and/or yield improvement. The purpose of the present work was to compare the yield of Paulista gherkin lines and their hybrids grown on a trellis net under field conditions. Four lines and their six single-cross hybrids were evaluated for yield and fruit production using the trellised net production system. Seedlings were produced in polystyrene trays with 128 cells, and transplanted to the middle of 1.20 m wide beds. Plants were trained without pruning on netting having 0.1 x 0.1 m openings. The experiment was conducted in a randomized block design with four replicates and seven plants per plot. Yield was expressed as number of fruits and total weight of fruits per plot. Length, width and fruit flesh thickness were also evaluated, with five samples per plot in two harvesting times. Hybrids and their parental lines were similar in fruit yield and quality. The trellised net was suitable for Paulista gherkin production and provided adequate support to the plants. The trellis technique is suitable to make harvesting easier and to improve fruit quality.

Maxixe Paulista é um novo tipo de maxixe derivado originalmente do cruzamento de Cucumis anguria var. anguria x Cucumis anguria var. longaculeatus, com características distintas de fruto e folhas. Apesar das linhagens elite apresentarem comportamento semelhante em termos de produção total e peso médio de frutos, algumas características são peculiares a cada uma delas. A combinação dessas características através de produção de híbridos poderia ser uma alternativa para aumentar a qualidade e/ou a produção de frutos. O objetivo desta pesquisa foi comparar a produção de linhagens e híbridos de Maxixe Paulista cultivadas em campo, com práticas de tutoramento em rede agrícola. Foram avaliadas quatro linhagens e seis híbridos simples, quanto ao comportamento e produção de frutos no sistema de cultivo tutorado em rede agrícola. As mudas foram obtidas em bandejas de poliestireno expandido e transplantadas para linha central de canteiros de 1,20 m de largura. As plantas foram conduzidas sem poda e tutoradas em rede agrícola com malha de 0,10 x 0,10 m. O delineamento experimental foi em blocos casualizados, com quatro repetições e parcela de sete plantas. A produção foi expressa em número e massa total de frutos/parcela. Avaliaram-se características de fruto como comprimento, largura e espessura de polpa, em amostragem de cinco frutos/parcela, em duas colheitas. A produção e a qualidade dos frutos dos híbridos foram equivalentes à das linhagens. A rede agrícola se mostrou adequada para o cultivo de Maxixe Paulista na forma tutorada. Esta técnica de condução facilita a colheita e melhora a qualidade dos frutos.

RESUMO

Paulista gherkin is a new gherkin type obtained by crossing Cucumis anguria var. anguria x C. anguria var. longaculeatus. It differs from common gherkin in its fruits and leaves. Elite lines of Paulista gherkin present similar performance for total yield and fruit weight but some have distinctive characteristics, including fruit and leaf attributes. The combination of these characteristics through production of Paulista gherkin hybrids could be an alternative for fruit quality and/or yield improvement. The purpose of the present work was to compare the yield of Paulista gherkin lines and their hybrids grown on a trellis net under field conditions. Four lines and their six single-cross hybrids were evaluated for yield and fruit production using the trellised net production system. Seedlings were produced in polystyrene trays with 128 cells, and transplanted to the middle of 1.20 m wide beds. Plants were trained without pruning on netting having 0.1 x 0.1 m openings. The experiment was conducted in a randomized block design with four replicates and seven plants per plot. Yield was expressed as number of fruits and total weight of fruits per plot. Length, width and fruit flesh thickness were also evaluated, with five samples per plot in two harvesting times. Hybrids and their parental lines were similar in fruit yield and quality. The trellised net was suitable for Paulista gherkin production and provided adequate support to the plants. The trellis technique is suitable to make harvesting easier and to improve fruit quality.

Maxixe Paulista é um novo tipo de maxixe derivado originalmente do cruzamento de Cucumis anguria var. anguria x Cucumis anguria var. longaculeatus, com características distintas de fruto e folhas. Apesar das linhagens elite apresentarem comportamento semelhante em termos de produção total e peso médio de frutos, algumas características são peculiares a cada uma delas. A combinação dessas características através de produção de híbridos poderia ser uma alternativa para aumentar a qualidade e/ou a produção de frutos. O objetivo desta pesquisa foi comparar a produção de linhagens e híbridos de Maxixe Paulista cultivadas em campo, com práticas de tutoramento em rede agrícola. Foram avaliadas quatro linhagens e seis híbridos simples, quanto ao comportamento e produção de frutos no sistema de cultivo tutorado em rede agrícola. As mudas foram obtidas em bandejas de poliestireno expandido e transplantadas para linha central de canteiros de 1,20 m de largura. As plantas foram conduzidas sem poda e tutoradas em rede agrícola com malha de 0,10 x 0,10 m. O delineamento experimental foi em blocos casualizados, com quatro repetições e parcela de sete plantas. A produção foi expressa em número e massa total de frutos/parcela. Avaliaram-se características de fruto como comprimento, largura e espessura de polpa, em amostragem de cinco frutos/parcela, em duas colheitas. A produção e a qualidade dos frutos dos híbridos foram equivalentes à das linhagens. A rede agrícola se mostrou adequada para o cultivo de Maxixe Paulista na forma tutorada. Esta técnica de condução facilita a colheita e melhora a qualidade dos frutos.