Jorge Valdez | Universidad Nacional de Cuyo (original) (raw)

Papers by Jorge Valdez

V Congreso Argentino de Microbiología Agrícola y Ambiental (Virtual). 15 al 17 septiembre de 2021, Sep 15, 2021

In this work the effect of time on in vitro culture of seed traces is evaluated. Without changing... more In this work the effect of time on in vitro culture of seed traces is evaluated. Without changing media, there was no decline in the number of rescued embryos for any cross within and up to 210 d of culture. After that period a decline was shown for varieties producing abundant callus from the external tegument. Direct germination of embryos increased in all crosses except for Blush Seedless x 73049, which stopped direct germination after 90 d. The polyembryony was advantageous for the cross Superior Seedless x Dawn Seedless, because it increased the percentage of normal plantlets. Multiple embryos showed a higher capacity to germinate in all cases. More embryos were obtained by excision and they presented a higher percentage of normal plantlets in comparison to plantlets obtained by embryos germinated directly. Embryos from the varieties Ruby Seedless, Blush Seedless and Bronx Seedless mainly produced normal plantlets while Crimson Seedless, Superior Seedless and Fantasy Seedless e...

Acta Horticulturae, 2000

... 110 (1): 109-112 Spiegel-Roy P., Baron J. and Sahar N., 1990. ... EE(ioo)VS DG(4oo) Hard Blus... more ... 110 (1): 109-112 Spiegel-Roy P., Baron J. and Sahar N., 1990. ... EE(ioo)VS DG(4oo) Hard Blush Centennial Ruby 22 * 47 19/4 * 30/14 NS * Ruby Fantasy Superior 42 NS 32 43/8 * 32/4 NS NS Soft Centennial Flame Superior 29 * 9 32/0 * 11 /0 NS NS Superior Dawn Madina 43 ...

Canadian Journal of Botany, 2005

Fifteen strains representing each Penicillium ser. Corymbifera taxa were compared using phenotypi... more Fifteen strains representing each Penicillium ser. Corymbifera taxa were compared using phenotypic and chemotaxonomic characters by cluster analysis and discriminant partial least squares regression. Variability in phenotypic expression of species strains resulted in a more fragmented classification compared with secondary metabolite expression. Although the observed phenotypic expression varied for strains cultured upon the same media, it was possible to classify strains into species groupings based only upon a few distinctive phenotypic traits. Data analysis of secondary metabolite profiles generated from HPLC-diode array dectection analysis gave reliable strain classification when more than one media type was employed. Depending on the species, Czapek yeast autolysate agar typically yielded the greatest chemical diversity; however, several metabolites (terrestric acid, corymbiferone, the corymbiferan lactones, and daldinin D) were only produced when strains were grown on either y...

Plant Pathology, 2009

A total of 147 samples of garlic (Allium sativum) bulbs affected by blue mould were obtained from... more A total of 147 samples of garlic (Allium sativum) bulbs affected by blue mould were obtained from a variety of agroclimatic districts between December 1999 and February 2000. Penicillium species were identified using both morphological and chemotaxonomic characteristics. Penicillium allii was the predominant species isolated (81·8%) in this survey and the only species proven to be pathogenic on garlic. Other species were isolated much less frequently: P. chrysogenum (13·7%), P. brevicompactum (2·8%), P. phoeniceum (0·9%), P. aurantiogriseum (0·6%) and P. flavigenum (0·2%). Colonies of P. allii could be classified into four morphotypes and their distribution seemed to be influenced by seed trade and agricultural practices. Penicillium allii isolates were grouped into three aggressiveness phenotypes (low, medium and high) based on their ability to cause disease during field trials on susceptible (Fuego INTA) and less susceptible (Castaño INTA) garlic cultivars. The number of surviving plants at 191 days after planting and postharvest bulb weight contributed the most towards aggressiveness modelling.

Persoonia - Molecular Phylogeny and Evolution of Fungi, 2012

Penicillium sect. Chrysogena was introduced by Frisvad & Samson (2004) for species having ter-or ... more Penicillium sect. Chrysogena was introduced by Frisvad & Samson (2004) for species having ter-or quarterverticillate branched conidiophores, relatively short phialides (< 10 µm) and smooth to finely roughened conidia. Four series and eight species (P. aethiopicum, P. chrysogenum, P. confertum, P. di podomyis, P. flavigenum, P. mononematosum, P. nalgiovense and P. persicinum) were accepted in this section. Only species lacking a sexual state were included, but a close affinity with Eupenicillium egyptiacum was suggested. Recently, single name nomenclature was applied in Penicillium and both asexual and sexual reproducing species were included in the redefined genus (Houbraken & Samson 2011). Using a multigene approach, Penicillium was divided into 25 sections and sect. Chrysogena was expanded to include species with a sexual state (P. egyptiacum, P. kewense, P. molle and P. sinaicum), and the recently resurrected species P. rubens. With the exception of P. chrysogenum, P. nal giovense and P. rubens, the species of sect. Chrysogena are primary soilborne (Frisvad & Samson 2004). Penicillium chrysogenum (and P. rubens) garner much research interest because of health ramifications that are a consequence of their occurrence in various food products (Pitt & Hocking 2009, Samson et al. 2010) and indoor environments, including damp building materials, indoor air and dust (

VALDEZ, J.G. & PICCOLO, R.J. Use of spectrophotometry as a tool to quantify the sporulation of 3H... more VALDEZ, J.G. & PICCOLO, R.J. Use of spectrophotometry as a tool to quantify the sporulation of 3HQLFLOOLXPDOOLL in garlic

Vitis Geilweilerhof, 1997

Revista Argentina de Microbiología, 2015

The use of a Neubauer chamber is a broadly employed method when cell suspensions need to be quant... more The use of a Neubauer chamber is a broadly employed method when cell suspensions need to be quantified. However, this technique may take a long time and needs trained personnel. Spectrophotometry has proved to be a rapid, simple and accurate method to estimate the concentration of spore suspensions of isolates of the genus Fusarium. In this work we present a linear formula to relate absorbance measurements at 530 nm with the number of microconidia/ml in a suspension.

Tropical Plant Pathology, 2014

Fusarium basal rot (FBR), which is caused predominantly by Fusarium oxysporum and F. proliferatum... more Fusarium basal rot (FBR), which is caused predominantly by Fusarium oxysporum and F. proliferatum, is the main limiting factor of onion crops. Resistant cultivars obtained in other countries do not behave as such in Argentina crop fields. The cultivars Antártica-INTA, Grano de Oro-Seminis, Valcatorce-INTA and TW-2007 (reported as tolerant) were tested with five Fusarium spp. isolates, using four inoculum concentrations. Disease incidence was recorded along 28 days and the area under disease progress curve was calculated. Diverse epidemiological models were fitted to experimental data. There were significant differences in the resistance level among cultivars, with TW-2007 being the most tolerant. Local Fusarium isolates were the most virulent ones. The concentration of 10,000 microconidia/ gram was the most lethal for all isolates. The absence of resistance to Fusarium in the four cultivars tested was confirmed. Inoculum concentration and isolate are critical factors in screening for resistance to FBR. Breeding based on the selection of genotypes against low virulence strains of Fusarium spp. and the presence of more aggressive strains in local fields may be one of the causes why varieties reported as resistant or tolerant behave as susceptible in our environment.

Fitopatologia Brasileira, 2006

A technique to measure the concentration of Penicillium allii conidia in damp chamber experiments... more A technique to measure the concentration of Penicillium allii conidia in damp chamber experiments by spectrophotometry was developed. A negative linear correlation (R²=0.56) was observed between transmittance at 340 nm and the concentration of P. allii conidia in water agar 0.05%. The equation that relates transmittance (T) with concentration (conidia mL-1) (y) is: y = 9.3 10(6) - 86497 T. The method was assayed by inoculating 43 P. allii strains in two garlic cultivars. The method proved to be more rapid than the traditional use of a hemocytometer with an improved accuracy. The CV of the number of conidia per hemocytometer reticule was of 35.04%, while the transmittance CV was of 2.73%. The extreme values chosen for T were 40 and 80 because the sensitivity of the method decreased when concentrations of conidia were out of this range.

Mastozoología …, 2007

... Ecology 58:1112-1119. © 2011 SAREM PIDBA, Facultad de Ciencias Naturales e Instituto Miguel L... more ... Ecology 58:1112-1119. © 2011 SAREM PIDBA, Facultad de Ciencias Naturales e Instituto Miguel Lillo Miguel Lillo 205 - Piso 4 - Sección de mamíferos (T4000JFE) - San Miguel de Tucumán, Tucumán República Argentina Tel.: (+54 381) 433-1339 pidba@arnet.com.ar.

Mastozoología …

Publikationsansicht. 45794484. Reseña de ¿The geographic mosaic of coevolution¿ de John N. Thomps... more Publikationsansicht. 45794484. Reseña de ¿The geographic mosaic of coevolution¿ de John N. Thompson (2007). ...