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Riga P.,NEIKER Basque Institute of Agricultural Research and Development
Horticulture Environment and Biotechnology | Year: 2015

We compared the growth of tomato plants ‘Jack’ grafted onto nine rootstocks with that of self-grafted and non-grafted plants, all grown in soilless culture in a heated greenhouse, to assess the capacity of commercial tomato rootstocks to improve fruit production and quality during the winter period under conditions of low temperature and light intensity. Neither vegetative development, estimated by the plastochron index, nor the thermal time required for a plastochron variation of one unit was significantly affected by the rootstock genotypes. Furthermore, the rootstock genotype did not mitigate the negative effects of low temperature and light conditions on fruit production. By contrast, the effect of the rootstock on the chemical composition of fruits and leaves was reflected by different allocation of N and C. Thus, the rootstocks affected the N contents of fruits and leaves and the C contents of fruits, but did not generally affect leaf C contents. The C/N ratios and mineral contents of fruits and leaves of grafted plants tended to decrease, leading to lower construction costs than in non-grafted or self-grafted plants. Thus, the use of rootstock reduced the energy needed to construct one unit of dry mass. Although the rootstock genotype did not affect fruit juiciness, titratable acidity (TA) or juice pH, it greatly influenced fruit quality parameters such as soluble solid content (SSC), SSC/TA ratio, juice electrical conductivity, ash contents, dry weight, firmness and puree consistency. Under the experimental conditions and in comparison with non-grafted and self-grafted plants, almost all rootstocks tended to be detrimental to the quality parameters considered. © 2015, Korean Society for Horticultural Science and Springer-Verlag GmbH.

Riga P.,NEIKER Basque Institute of Agricultural Research and Development | Medina S.,CSIC - Center of Edafology and Applied Biology of the Segura | Garcia-Flores L.A.,CSIC - Center of Edafology and Applied Biology of the Segura | Gil-Izquierdo A.,CSIC - Center of Edafology and Applied Biology of the Segura
Food Chemistry | Year: 2014

We evaluated the effect of cultivar and solar radiation on the melatonin content of Capsicum annuum (pepper) and Solanum lycopersicum (tomato) fruits. The melatonin content of red pepper fruits ranged from 31 to 93 ng g -1 (dry weight). The melatonin content of tomato ranged from 7.5 to 250 ng g-1 (dry weight). We also studied the effect of ripeness on melatonin content and identified one group of pepper cultivars in which the melatonin content increased as the fruit ripened and another in which it decreased as the fruit ripened. Under shade conditions, the melatonin content in most of tomato cultivars tended to increase (up to 135%), whereas that of most pepper cultivars decreased (to 64%). Overall, the results also demonstrated that the melatonin content of the fruits was not related to carbon fluxes from leaves. © 2014 Elsevier Ltd. All rights reserved.

Riga P.,NEIKER Basque Institute of Agricultural Research and Development | Benedicto L.,NEIKER Basque Institute of Agricultural Research and Development | Garcia-Flores L.,CSIC - Center of Edafology and Applied Biology of the Segura | Villano D.,CSIC - Center of Edafology and Applied Biology of the Segura | And 2 more authors.
Journal of Food Composition and Analysis | Year: 2016

In this study, we explored the capacity of different tomato rootstocks to improve the nutritional value of tomatoes grown in a greenhouse during the winter-spring period under low temperature and light conditions. The results showed that relative to nongrafted plants, some grafted rootstocks either did not affect or had detrimental effects on the nutritional parameters measured. In addition, the amount of serotonin was significantly lower in tomatoes from all grafted rootstocks than in tomatoes from the nongrafted plants. Nevertheless, relative to the nongrafted plants, some grafted treatments increased total macroelements (by 1.16 times), total microelements (by 1.43 times), protein content (by 17%), free total and essential amino acids (by respectively 23% and 19%), total phenolic compounds (by 11%), vitamin C (by 13.8%), lycopene (by 48%), and also total hydrocinnamic acids (by 67%) and flavonoids (by 279%). As the grafted treatments did not increase the tomato yield, we hypothesize that these compounds accumulated in the tomatoes due to the lack of increased biomass, which prevented a dilution effect on the compounds of interest in the fruits. © 2015 Elsevier Inc.

Lopez S.,NEIKER Basque Institute of Agricultural Research and Development | Goldarazena A.,NEIKER Basque Institute of Agricultural Research and Development
Psyche (New York) | Year: 2012

In January 2009, the windstorm "Klaus" struck the southern part of France, affecting 37.9 million m 3 of maritime pine Pinus pinaster Aiton (Pinales: Pinaceae). This breeding plant material favored the outbreak of Ips sexdentatus (Börner) (Coleoptera: Curculionidae: Scolytinae). As much of this timber is imported to the Basque Country (northern Spain), a potential risk to conifer stands is generated, due to the emergence of the incoming beetles. Thus, flight dynamics and beetle abundance were compared in different sawmills, according to the timber species (either local P. radiata D. Don or imported P. pinaster). A maximum flight peak of I. sexdentatus was observed in mid-June in P. pinaster importing sawmills, whereas a second lighter peak occurred in September. In contrast, only a maximum peak in mid-June was observed in P. radiata inhabiting beetles, being significantly smaller than in local P. pinaster trading sawmills. In addition, significant differences were found between imported P. pinaster and P. radiata regarding the number of insects beneath the bark. The development of IPM strategies for controlling I. sexdentatus populations is recommended, due to the insect abundance found in P. pinaster imported timber. Copyright © 2012 Sergio Lpez and Arturo Goldarazena.

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