Papers by Alejandra Yommi
Acta horticulturae, Apr 1, 1998
Argentina has around 1000 ha of kiwifruit orchards in Buenos Aires Province. This country is reco... more Argentina has around 1000 ha of kiwifruit orchards in Buenos Aires Province. This country is recognized as free of Pseudomonas syringae pv. actinidiae (Psa). In 2013, the National Sanitary Service (SENASA) imposed measures to avoid the entrance of this pathogen to the kiwifruit production areas. In this way, a vigilance plan was established and the introduction of plant material was regulated. In March 2015, three infected samples with Psa were detected in orchards at the SouthEast of Buenos Aires Province and they were immediately eradicated by SENASA. The objective of this work was to identify the bacteria associated with kiwifruit leaf spots and flower blights in commercial orchards of Actinidia deliciosa 'Hayward' at Buenos Aires Province, during the 2015-2016 growing season. On spring and autumn seasons, plant tissues were collected from a 100 ha area located in the North and SouthEast of this Province. Bacterial isolates were obtained from flowers and leaves by tissues mashing and inoculation on nutrient agar supplemented with 5% sucrose (NSA). The primary identification of isolates was performed by biochemical and physiological tests. To confirm their identity, duplex-PCR tests were performed, including negative and positive controls (no template and Psa DNA, respectively). From symptomatic and asymptomatic samples, 120 bacterial isolates were obtained. Thirty of these isolates were morphologically similar to Psa, forming white-creamy, convex, domed and mucoid colonies on NSA. Also, all of them were Gram-negative, produced a green fluorescent pigment on King's B medium and their metabolism was aerobic. However, none of these strains examined produced any bands following the amplification by PCR with Psa specific primers. Our results show the absence of Psa in the analyzed samples. Further studies are needed to identify these non-Psa bacteria associated with kiwifruit leaf spots and flower blights.
Introducción La producción de kiwi (Actinidia deliciosa (A. Chev.) C. S. Liang et. A.R. Ferguson)... more Introducción La producción de kiwi (Actinidia deliciosa (A. Chev.) C. S. Liang et. A.R. Ferguson) en Argentina ha crecido sostenidamente en los últimos años. Este cultivo se desarrolla principalmente en la provincia de Buenos Aires, en el norte (La Plata, Baradero, San Pedro y Mercedes) y en el sudeste (partidos de Gral. Pueyrredón, Gral. Madariaga, Gral. Alvarado, Balcarce y Mar Chiquita). El sudeste ha duplicado la superficie dedicada al kiwi y se ha convertido en la zona más importante del país al producir la mitad del volumen nacional. En la actualidad alrededor de 800 ha se encuentran implantadas con este cultivo en el país, de las cuales el 88 % está en producción (SINAVIMO, 2014). Las enfermedades constituyen uno de los principales factores limitantes para el desarrollo del cultivo de kiwi. Entre ellas, las de origen bacteriano son una de las causas de mayores pérdidas en la producción a nivel mundial (Gubler y Conn, 1994). Pseudomonas syringae pv. syringae (Pss), P. syringae pv. actinidiae (Psa), P. viridiflava y P. marginalis son bacterias patógenas que afectan al cultivo. Han sido reportadas causando manchas necróticas y angulares en hojas, tizón de flores, caída de botones florales y cancros en ramas (
Journal of Stored Products Research, Dec 1, 2017
The dynamic of oxygen (O 2) and carbon dioxide (CO 2) concentration was characterized in soybean ... more The dynamic of oxygen (O 2) and carbon dioxide (CO 2) concentration was characterized in soybean (Glycine max (L.)) samples hermetically stored in glass jars at 15, 25 and 35 C and 13, 15 and 17% moisture content (m.c., wet base). Two correlations were used for smoothing gas concentration in time: linear and exponential. Then, the respiration rate at each temperature and m.c. combination was calculated as storage time progressed and oxygen was consumed and two predictive models for respiration were proposed: Model I (temperature and m.c. dependent) and Model II (temperature, m.c. and oxygen dependent). It was observed that respiration rate increased with storage m.c. and temperature. However, respiration rate was not mainly affected by O 2 until a critical concentration limit of about 2% was reached. Respiration rates were from 0.341 to 22.684 mg O 2 /(kgDM d) and from 0.130 to 20.272 mg CO 2 /(kgDM d) for a range of storage condition of 13e17% m.c. and 15e35 C temperature. The respiration rate of soybean seeds obtained in this study resulted significantly lower than the rates reported in the literature for other grains at similar temperature and a w (water activity) storage condition. For hermetic storage simulations in which O 2 concentration is not expected to drop below 2%, the simplest model (Model I) could be used, but if the O 2 concentration of the hermetic system is expected to be depleted, Model I would under estimate the time at which O 2 is consumed, and thus a model with O 2 dependency is recommended instead (Model II).
Horticultura Argentina 39 (100) : 357-397 (2020), Dec 21, 2020
The use of saliva samples for the diagnosis of severe acute respiratory syndrome-Coronavirus-2 (S... more The use of saliva samples for the diagnosis of severe acute respiratory syndrome-Coronavirus-2 (SARS-CoV-2) provides several advantages over the use of nasopharyngeal (NP) swabs, such as comfort, ease of self-collection, less use of personal protective equipment, and protection of healthcare personnel from transmission. This review included current studies using saliva samples for the detection of SARS-CoV-2, comparing its sensitivity, cycle threshold, and specificity with those of NP swab. In the literature, the sensitivity rates of saliva samples in the diagnosis of SARS-CoV-2 ranged from 70% to 98%. Despite different opinions, we concluded that saliva is a reliable sample for the detection of SARS-CoV-2. However, studies with large samples and comparing different diagnostic methods are needed to reach precise and reliable results and include saliva collection in diagnostic guidelines.
RIA, Revista de Investigaciones Agropecuarias, 2019
Todos los derechos reservados Hecho el depósito que prevé la ley 11.723 Impreso en Argentina Se p... more Todos los derechos reservados Hecho el depósito que prevé la ley 11.723 Impreso en Argentina Se permite la reproducción total o parcial. Agradecemos citar la fuente. Kiwi : manejo del suelo, riego y fertilización / Alejandra Yommi ... [et al.] ; coordinación general de Alejandra Yommi ; editado por Alejandra Yommi ; prólogo de Daniel Vázquez.-1a ed.-Balcarce, Buenos Aires : Ediciones INTA, 2018. Libro digital, PDF Archivo Digital: descarga y online ISBN 978-987-521-930-4 Prólogo Índice Conceptos teóricos y técnicos del manejo del suelo, riego y fertilización del kiwi. por Enrique E. Sánchez y Enrique Manzo Introducción Riego y calidad de agua Fertilización Diagnóstico nutricional Cantidad versus calidad Fertirriego Aplicaciones foliares Manejo del suelo Síntesis práctica Consideraciones finales Bibliografía Uso y construcción de la tecnología de riego para kiwi en el sudeste bonaerense
Journal of Berry Research, 2020
BACKGROUND: It is known that 1-MCP delays softening in kiwifruit. Time to ripen (eating-window) a... more BACKGROUND: It is known that 1-MCP delays softening in kiwifruit. Time to ripen (eating-window) and its variability are considered useful for planning commercial strategies. However, few studies report the firmness and quality changes during long-term cold storage. OBJECTIVES: To study the effects on ripening and sensory attributes of different 1-MCP treatments during long (180 d) and very long-term (≥210 d) cold storage. Then, the optimal 1-MCP dose was applied to determine the time to ripen after cold storage for 30 to 240 d. METHODS: Kiwifruits were treated with 1-MCP: 0.0 (control), 0.5 and 1.0μL L–1. Maturity indices and sensory analysis were achieved after 180 and 210 d of storage at 0 °C. Ethylene production was also measured. Firmness and number of fruits at eating-ripe state (at 20 °C) were monthly determined after 30 to 240 d of cold storage. RESULTS: 1-MCP (1.0μL L–1) delayed kiwifruit softening and prolonged the storage to up 180 d. Longer periods were associated to loss...
Acta Horticulturae, 2015
The objective of the present work was to study the effect of the harvest maturity on the response... more The objective of the present work was to study the effect of the harvest maturity on the response to the application of 1-methylcyclopropene (1-MCP) in prestorage of kiwifruit 'Hayward' produced in the Mar del Plata area (38°0'S, 57°30'W), Buenos Aires, Argentina. The kiwifruits were harvested at 142, 177 and 190 days after bloom (MS1, MS2 and MS3, respectively); half of the fruits were treated with 1 µl L-1 1-MCP for 24 h and the others were untreated (controls). Fruits were stored for six months at 0°C and 95% RH. Firmness (N), color (CIELab*), soluble solids content (SSC) and titratable acidity (TA) were analyzed at the end of the cold storage (ECS) and shelf-life (seven days at 20°C). Maturity stage at harvest affected the color, SSC and TA at ECS and shelf-life without significant effects of 1-MCP treatment. The 1-MCP application increased fruit firmness in both at ECS and shelf-life, especially at MS1. The MS1 presented the lowest values of SSC and TA, being the SSC content less than the adequate to satisfy the consumers. The fruits treated with 1-MCP matured normally, without physiological disorders, or external symptoms of toxicity. In conclusion, the 1-MCP treatment delayed softening of kiwifruit in the three maturity stages. This effect was greater in MS1, but this maturity stage showed a sub-optimal SSC values for consumption.
p.61-68El objetivo de este trabajo fue desarrollar tecnología para mantener la calidad comercial ... more p.61-68El objetivo de este trabajo fue desarrollar tecnología para mantener la calidad comercial de calabacitas tipo buttemut o coreanas (Cucúrbita moschata Duch.) y así alcanzar períodos del año de mayores precios. Para disminuir la deshidratación y reducir las podredumbres, principales causas de deterioro en este producto, se evaluó el uso de técnicas como embolsado, aplicación de cera, cal y almacenamiento refrigerado, solas o combinadas. A la cosecha y cada 4 semanas hasta alcanzar seis meses de conservación, se efectuaron determinaciones de componentes de la calidad como porcentaje de pérdida de peso, firmeza, color, contenido de sólidos solubles y grado de ahuecado interno, además se registraron las podredumbres y los agentes causales. Exceptuando los tratamientos que incluyeron el uso de bolsas de polietileno, no se encontraron ventajas del uso de las técnicas probadas (cera, cal, cera + cal, almacenamiento refrigerado) con respecto al testigo en ninguna de las variables medi...
International Postharvest Science Conference Postharvest 96, 1998
Acta Horticulturae, 2018
Argentina has around 1000 ha of kiwifruit orchards in Buenos Aires Province. This country is reco... more Argentina has around 1000 ha of kiwifruit orchards in Buenos Aires Province. This country is recognized as free of Pseudomonas syringae pv. actinidiae (Psa). In 2013, the National Sanitary Service (SENASA) imposed measures to avoid the entrance of this pathogen to the kiwifruit production areas. In this way, a vigilance plan was established and the introduction of plant material was regulated. In March 2015, three infected samples with Psa were detected in orchards at the SouthEast of Buenos Aires Province and they were immediately eradicated by SENASA. The objective of this work was to identify the bacteria associated with kiwifruit leaf spots and flower blights in commercial orchards of Actinidia deliciosa 'Hayward' at Buenos Aires Province, during the 2015-2016 growing season. On spring and autumn seasons, plant tissues were collected from a 100 ha area located in the North and SouthEast of this Province. Bacterial isolates were obtained from flowers and leaves by tissues mashing and inoculation on nutrient agar supplemented with 5% sucrose (NSA). The primary identification of isolates was performed by biochemical and physiological tests. To confirm their identity, duplex-PCR tests were performed, including negative and positive controls (no template and Psa DNA, respectively). From symptomatic and asymptomatic samples, 120 bacterial isolates were obtained. Thirty of these isolates were morphologically similar to Psa, forming white-creamy, convex, domed and mucoid colonies on NSA. Also, all of them were Gram-negative, produced a green fluorescent pigment on King's B medium and their metabolism was aerobic. However, none of these strains examined produced any bands following the amplification by PCR with Psa specific primers. Our results show the absence of Psa in the analyzed samples. Further studies are needed to identify these non-Psa bacteria associated with kiwifruit leaf spots and flower blights.
XXIII Workshop de Investigadores en Ciencias de la Computación (WICC 2021, Chilecito, La Rioja), 2021
Revista de la Facultad de Ciencias Agrarias Universidad Nacional de Cuyo, Jul 19, 2002
The effects of maturity stage at harvest: light and dark reds and the use of modified atmosphere ... more The effects of maturity stage at harvest: light and dark reds and the use of modified atmosphere packaging (LDPE, 11 and 40 µ) on sweet cherries quality kept at 0 °C were evaluated. After storage, fruit was exposed to room temperature for 3 days. Quality was measured in terms of weight loss (%), color (hue angle), firmness, soluble solids content, pedicel aspect and rot.
Revista De La Facultad De Ciencias Agrarias, Mar 1, 2002
The effects of maturity stage at harvest: light and dark reds and the use of modified atmosphere ... more The effects of maturity stage at harvest: light and dark reds and the use of modified atmosphere packaging (LDPE, 11 and 40 µ) on sweet cherries quality kept at 0 °C were evaluated. After storage, fruit was exposed to room temperature for 3 days. Quality was measured in terms of weight loss (%), color (hue angle), firmness, soluble solids content, pedicel aspect and rot.
III Congreso Argentino de Biología y Tecnología Postcosecha, Modalidad virtual [ARG], 26-30 julio 2021., 2021
En Argentina se importan alrededor de 12.000 t.año-1 de kiwi para abastecer la demanda interna. E... more En Argentina se importan alrededor de 12.000 t.año-1 de kiwi para abastecer la demanda interna. El 60-70% de los frutos proviene de Chile. El sudeste de la provincia de Buenos Aires (SEB) concentra la mayor parte de la producción de kiwi nacional. La zona presenta características edafoclimáticas adecuadas para lograr altas producciones y frutos de excelente calidad. Esto es acompañado de protocolos de cosecha desarrollados especialmente para la región. Desde junio a noviembre, el kiwi del SEB compite en el mercado con frutos chilenos, los que reciben un sobreprecio del 20% respecto al local, considerando un mismo tipo de envase y calibre. No existe información clara de la forma en que incide la procedencia del fruto en la percepción de calidad que tienen los agentes del mercado mayorista. Tanto los kiwis importados como los regionales cumplen los estándares nacionales establecidos para su comercialización, pero hay evidencia que sugiere que la característica de sabor es superior en los productos de la región, atributo que el mercado mayorista pareciera no valorar suficientemente. El objetivo de este trabajo fue generar datos en relación a la calidad del kiwi importado y regional. De acuerdo a la disponibilidad en el mercado mayorista de Mar del Plata, se tomaron muestras de 11 productores del SEB (KiwiSEB) y de 2 exportadores chilenos (KiwiImportado) en septiembre/2020 (T1) y de 8 productores del SEB y de 2 exportadores chilenos, en octubre/2020 (T2). De cada muestra se seleccionaron al azar 3 repeticiones de 15 frutos. Se evaluó la firmeza de la pulpa (penetrómetro EFFEGI), contenido de sólidos solubles totales (SST, refractometría), y acidez titulable (AT, volumetría ácido-base). En T1 y T2, la mayoría de las muestras de KiwiSEB así como de KiwiImportado se encontraron dentro del rango aceptable de madurez comercial (Firmeza: 0,6-1,2 kgf). Tanto en T1 como en T2, las muestras de KiwiSEB presentaron valores adecuados de AT y SST, asociados a un buen balance entre dulzor y acidez y a un buen sabor. Esto está relacionado con el alto contenido de materia seca que acumulan los frutos del SEB a la cosecha. En algunas muestras de KiwiImportado, sin embargo, se determinó un bajo contenido de SST y sobre todo de AT, asociado a un fruto de poco sabor. La consistencia en los resultados respecto a la elevada calidad organoléptica del kiwi del SEB, en ambos tiempos de evaluación, permite continuar en camino hacia algún tipo de diferenciación del producto en el mercado, su valorización y la difusión de estas características propias en los diferentes canales de comercialización y en los consumidores.
Visión Rural 27 (132) : 52-54 (mayo-junio 2020), May 1, 2020
Postharvest Biology and Technology, 2020
Chitosan is obtained at industrial scale through a process of alkaline deacetylation of chitin th... more Chitosan is obtained at industrial scale through a process of alkaline deacetylation of chitin the major waste of shrimp industry. Its utilization could both diminish industrial environmental impact and add value to foods and other industrial products. In this study, an industrial chitosan obtained in Argentina and a commercial chitosan were physicochemically characterized and evaluated as edible coating for biopreservation of minimally processed lettuce. Based on Nuclear Magnetic Resonance, X-ray diffraction and thermogravimetric and viscosimetric assays we conclude that both biopolymers have similar molecular weight and deacetylation degree. The chitosan coatings were applied by spraying to lettuce leaves that had been removed and cleaned after the harvest. Each sample composed by four whole leaves, packed into a low-density polyethylene bag, was stored at 4°C for 15 d. Microbial quality, weight and color losses, antioxidant contents, stomatal closure and sensorial attributes were evaluated during storage. An initial reduction of 2 log in molds and yeast counts were obtained for both types of chitosan coatings. As a result, the counts remained below the limit value of 6 log for 12 d in the chitosan coatings, while in the control samples this limit was reached 6 d after storage. Total mesophilic bacteria counts were also reduced by both types of chitosan coatings, keeping counts under the threshold value of 7 log for 12 d while in control samples this value was exceeded at 9 d. Both chitosans increased chlorophyll content, total phenolic compounds and antioxidant activity in lettuce leaves during the storage. Besides, the leaf weight loss was minimized by both chitosan coatings, in accordance to a higher proportion of stomatal partial closure as seen by SEM. The overall visual quality was not affected by chitosan coatings. In conclusion, the industrial chitosan showed similar effects on stored minimally processed lettuce than the commercial chitosan adding value to a material that is currently considered a waste.
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Papers by Alejandra Yommi