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Interactive effects of deficit irrigation and shoot and cluster thinning on grapevine cv. Tempranillo. Water relations, vine performance and berry and wine composition
No full textThe effects of crop level and irrigation on water relations, yield, grape and wine composition were studied during two seasons in a Tempranillo vineyard in Spain. Irrigation was applied at two levels: R2 (with mild deficit irrigation applied during all the season) and R1 (with more severe water stress applied before veraison). Deficit irrigated vines were compared to a non-irrigated control. Crop levels imposed resulted in 11, 20, and 27 clusters per vine. Over all treatments, yield and ratio of leaf area to yield (LA: Y) were different between years: 4.4 and 16.3 t ha(-1) and 1.72 and 0.88 m(2) kg(-1) in 2005 and 2006, respectively. In 2005, large differences in grape and wine composition occurred among non-irrigated and the irrigated treatments, but not between R1 and R2 treatments. Wines from non-irrigated vines were more acid, had higher total anthocyanins, and higher color intensity. In 2006, irrigation had less effect on grape and wine variables. The effect of shoot and cluster thinning on wine composition was different between seasons due to the different crop load values between years. Grape composition was negatively affected by high crop level only for values of LA: Y lower than 1.5 m(2) kg(-1)
Evolutionary analysis of tomato Sw-5 resistance-breaking isolates of Tomato spotted wilt virus
No full textTomato spotted wilt virus (TSWV) causes severe economic losses in many crops worldwide and often overcomes resistant cultivars used for disease control. Comparison of nucleotide and amino acid sequences suggested that tomato resistance conferred by the gene Sw-5 can be overcome by the amino acid substitution C to Y at position 118 (C118Y) or T120N in the TSWV movement protein, NSm. Phylogenetic analysis revealed that substitution C118Y has occurred independently three times in the studied isolates by convergent evolution, whereas the substitution T120N was a unique event. Analysis of rates of non-synonymous and synonymous changes at individual codons showed that substitution C118Y was positively selected
Sustratos, manejo del clima, automatización y control de sistemas de cultivo sin suelo
Get PDFAl comparar tipos diferentes de invernaderos dotados de niveles diversos de equipamiento y tecnología, incluyendo la opción del cultivo sin suelo,
desde el más simple con inversiones mínimas hasta el que cuenta con mayor
tecnología, aplicados al caso concreto del cultivo del pimiento, en una zona
con clima mediterráneo, los resultados de Fernández-Zamudio et al. (2006)
concluyen que los cuatro niveles objeto del estudio son rentables, pero también queda claro que mayor inversión no implica mayor rentabilidad. En un
estudio del mismo tipo en tomate, al aumentar el nivel de tecnología, aumentan los costes de producción totales debido a la intensificación del cultivo.
Las diferencias de rentabilidad entre los niveles tecnológicos son pequeñas
y la opción por uno u otro dependerá finalmente de las estrategias de viabilidad de la explotación a mediano y largo plazo, ya que la explotación de
mayor nivel se situará mejor tecnológicamente para afrontar con eficacia un
mercado cambiante (Fernández-Zamudio et al., 2010). Por lo tanto, algunas
cuestiones previas que hay que decidir para la inversión en tecnología en la
horticultura protegida son, cuál es el mercado de destino de los productos,
cuáles son las exigencias de este mercado, qué inversiones y qué técnicas hay
que aplicar para producir y cumplir esos objetivos. La capacidad mayor o
menor de regular las condiciones del clima del invernadero, es una de las
decisiones que habría que tomar, ya que dicha capacidad es una de las herramientas más potentes del cultivo protegido.
Mejorar las condiciones de control del invernadero supone no solo la mejora de la producción en rendimiento y en calidad, sino también un uso más eficiente de los insumos (agua, fertilizantes, CO2
, combustibles, etc.), que
resulta en una práctica de la horticultura más sostenible con el medioambiente y con los recursos. Este mejor manejo del sistema de producción en
invernadero va ligado al buen conocimiento de las funciones y los procesos
que tienen lugar en las plantas y a su aprovechamiento. La obtención de información sobre dichos procesos por medio de sensores adecuados, técnicas
de medida y el desarrollo de algoritmos de control, que puedan aprovechar
dichas informaciones, son necesidades fundamentales para avanzar en el
control y el manejo de los invernaderos. Todavía hay mucho trabajo por hacer para el desarrollo pleno de estos sistemas al nivel comercial.
Sin lugar a dudas, cualquier planteamiento actual de mejora y optimización del manejo de los invernaderos, debe pasar el filtro de la sostenibilidad,
tanto al incorporar mejoras tecnológicas en relación con los materiales de
cubierta, como con los sistemas de control climático. Aplicar criterios de
manejo basados en los requerimientos del cultivo y aprender a aprovechar
sus señales de respuesta deberá, cada vez más, formar parte de las herramientas de control del sistema (Bakker et al., 2008)
Sustratos, manejo del clima, automatización y control de sistemas de cultivo sin suelo
No full textEl suelo, medio en el que tienen lugar funciones de tanta importancia para
la vida de las plantas, con frecuencia tiene condiciones limitantes que, en diferentes
grados, impiden buenos resultados agronómicos. Por este motivo, en la
horticultura, es frecuente reemplazar el suelo natural por sustratos de origen
diverso, que en alguna o en todas las fases de un cultivo permiten superar esas
condiciones limitantes y colocar el sistema radicular y la planta completa en
una situación más cercana a la óptima para su alimentación hídrica y mineral.
La posibilidad de aprovechar como sustrato hortícola la diversidad de materiales
disponibles en nuestro entorno, está supeditada al buen conocimiento
de sus propiedades, con el fin de saber si requieren alguna preparación previa
a su uso, decidir sus aplicaciones y adoptar las técnicas de manejo pertinentes.
Hay una preocupación por llegar a acuerdos sobre los criterios y métodos
que permitan normalizar y homogeneizar la caracterización de los sustratos
en horticultura, que se pone de manifiesto en numerosos trabajos (de Boodt
y Verdonck, 1972; Bunt, 1983; Andre, 1987; Gras, 1987; Arrieta y Terés, 1992;
Cadahía y Eymar, 1993; Diego, 1992; González et al., 1992; Guerrero et al., 1992;
Martínez, 1992; Brun, 1993; Noguera, 1999; Abad et al., 2001). El Grupo de
Trabajo de “Mejoradores de suelo y sustratos de cultivo” del Comité Técnico
de Normalización AEN/CTN 142 de AENOR, ha efectuado un esfuerzo notable,
que ha permitido avanzar considerablemente en la actualización y el establecimiento
de normas para la caracterización de los sustratos, acordes con la
normativa europea (CEN/TC 223) (CEN Normas UNE-EN, 2001-2008) (Abad et
al., 2001; Rodríguez y Vidal, 2004). Especialmente esta labor es indispensable
en el caso de nuevos productos o nuevas aplicaciones (Zuang y Musard, 1986;
Abad et al., 1992; García et al., 1992; Ordovás et al., 1992; Maloupa et al., 1993;
Martínez y Abad, 1993; Benoit y Ceustermans, 1995; Fakhri et al., 1995; Martínez
y Abdel-Fattah, 1995; Arias, 2003)
Fruit regulates seasonal expression of flowering genes in alternate-bearing 'Moncada' mandarin
No full textBackground and Aims The presence of fruit has been widely reported to act as an inhibitor of flowering in fruit trees. This study is an investigation into the effect of fruit load on flowering of 'Moncada' mandarin and on the expression of putative orthologues of genes involved in flowering pathways to provide insight into the molecular mechanisms underlying alternate bearing in citrus. Methods The relationship between fruit load and flowering intensity was examined first. Defruiting experiments were further conducted to demonstrate the causal effect of fruit removal upon flowering. Finally, the activity of flowering-related genes was investigated to determine the extent to which their seasonal expression is affected by fruit yield. Key Results First observations and defruiting experiments indicated a significant inverse relationship between preceding fruit load and flowering intensity. Moreover, data indicated that when fruit remained on the tree from November onwards, a dramatic inhibition of flowering occurred the following spring. The study of the expression pattern of flowering-genes of on (fully loaded) and off (without fruits) trees revealed that homologues of FLOWERING LOCUS T (FT), SUPRESSOR OF OVEREXPRESSION OF CONSTANS 1 (SOC1), APETALA1 (AP1) and LEAFY (LFY) were negatively affected by fruit load. Thus, CiFT expression showed a progressive increase in leaves from off trees through the study period, the highest differences found from December onwards (10-fold). Whereas differences in the relative expression of SOC1 only reached significance from September to mid-December, CsAP1 expression was constantly higher in those trees through the whole study period. Significant variations in CsLFY expression only were found in late February (close to 20%). On the other hand, the expression of the homologues of TERMINAL FLOWER 1 (TFL1) and FLOWERING LOCUS C (FLC) did not appear to be related to fruit load. Conclusions These results suggest for the first time that fruit inhibits flowering by repressing CiFT and SOC1 expression in leaves of alternate-bearing citrus. Fruit also reduces CsAP1 expression in leaves, and the significant increase in leaf CsLFY expression from off trees in late February was associated with the onset of floral differentiation
Nutritional Responses of Citrus Rootstocks to Salinity: Performance of the New Hybrids Forner-Alcaide 5 and Forner-Alcaide 13
No full textThis study assesses the nutritional behavior of the new citrus rootstocks Forner-Alcaide no.5 (FA-5) and Forner-Alcaide no. 13 (FA-13) under saline conditions compared to that of their parents, Cleopatra mandarin (CM) and Poncirus trifoliata (PT). Eighteen month-old plants grafted with Valencia orange scions were used in the experiment. The plants were grown in a greenhouse and irrigated over an. eight-week period with nutrient solutions to which, different amounts of sodium chloride (NaCl) had been added, namely 0, 20, 40 and 60 mM. Relative growth and the uptake of major mineral elements [nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), and magnesium (Mg,)] were then determined. It was noted that the reduction in relative growth caused by salt treatment was greater in plants grafted on PT than those on FA-13, FA-5 and CM. increasing the salt level in the growth medium reduced the absorption of the above mineral elements in all scion-rootstock combinations. However; this decrease was generally more marked in plants grafted on PT than in those on CM and FA-5. Plants on FA-13 showed an intermediate behavior Positive correlations were found between growth and mineral element uptake by salt treated plants. Nutrient uptake was also plotted against chloride (Cl) and sodium (Na) concentrations in leaves and roots at increasing salt levels. This showed that N absorption was closely correlated (inversely) with Cl content in leaves, whereas K, Ca and Mg uptakes were correlated (inversely) with Na concentration in roots. This suggests that the accumulation of saline ions impacts growth and nutrient uptake by citrus plants
Genetic variability and evolutionary analyses of the coat protein gene of Tomato mosaic virus
No full textTomato mosaic virus (ToMV), a member of the genus Tobamovirus, infects several ornamental and horticultural crops worldwide. In this study, the nucleotide sequences of the coat protein gene of worldwide ToMV isolates were analyzed to estimate the genetic structure and diversity of this virus and the involved evolutionary forces. The phylogenetic analysis showed three clades with high bootstrap support: Clade I contained three ToMV isolates from Brazil collected from pepper, Clade II comprised one Brazilian ToMV isolate from pepper, and Clade III was composed of ToMV isolates collected from different plant hosts (pepper, tomato, eggplant, lilac, camellia, dogwood, red spruce, etc.) and water (from melting ice, lakes and streams) from different countries: USA, Brazil, Korea, Germany, Spain, Denmark (Greenland), China, Taiwan, Malaysia, Iran, and Kazakhstan. With the exception of Brazil, nucleotide diversity within and between different geographic regions was very low, although statistical analyses suggested some gene flow between most of these regions. Our analyses also suggested a strong negative selection which could have contributed to the genetic stability of ToMV
The monoterpene limonene in orange peels attracts pests and microorganisms.
No full textPlant volatiles include terpenoids, which are generally involved in plant defense, repelling pests and pathogens and attracting insects for herbivore control, pollination and seed dispersal. Orange fruits accumulate the monoterpene limonene at high levels in the oil glands of their fruit peels. When limonene production was downregulated in orange fruits by the transgenic expression of a limonene synthase (CitMTSE1) in the antisense configuration, these fruits were resistant to the fungus Penicillium digitatum (Pers.) Sacc. and the bacterium Xanthomonas citri subsp. citri and were less attractive to the medfly pest Ceratitis capitata. These responses were reversed when the antisense transgenic orange fruits were treated with limonene. To gain more insight into the role of the limonene concentration in fruit responses to pests and pathogens, we attempted to overexpress CitMTSE1 in the sense configuration in transgenic orange fruits. Only slight increases in the amount of limonene were found in sense transgenic fruits, maybe due to the detrimental effect that excessive limonene accumulation would have on plant development. Collectively, these results suggest that when limonene reaches peak levels as the fruit develops, it becomes a signal for pest and pathogen attraction, which facilitate access to the fruit for pulp consumers and seed dispersers
Clavibacter michiganensis subsp michiganensis, a Seedborne Tomato Pathogen: Healthy Seeds Are Still the Goal
No full textThe invasive South American tomato pinworm, Tuta absoluta, continues to spread in Afro-Eurasia and beyond: The new threat to tomato world production
No full textThe economic and ecological effects of invasive species, notably pests (Mack et al. 2000; Suckling and Brockerhoff 2010; Ragsdale et al. 2011), are now widely recognized (Thomas 1999; Pysek and Richardson 2010). The South American tomato pinworm Tuta absoluta Meyrick (Lepidoptera: Gelechiidae) is an invasive pest, native to South America which was detected in eastern Spain at the end of 2006. Since then, T. absoluta has spread to the European and the North African Mediterranean Basin countries where it has become a serious agricultural threat to tomato production in both greenhouse and outdoor tomato crops (see Desneux et al. 2010 for a thorough review). This pest spreads rapidly and its status in the world has completely changed within only a few years from a South American tomato pest to a major threat to tomato world production. In this letter, we update the available information on the current distribution of T. absoluta in the world. Moreover, we describe and discuss the threat represented by the rapid spread of T. absoluta and how this pest is going to change world tomato production