Covered smut of barley (Hordeum vulgare), caused by Ustilago hordei, is a seed-borne disease. To identify and map disease resistance genes, current Canadian barley cultivars, parents of six barley mapping populations, and four differentials namely ‘Hannchen’ (Ruh1), ‘Excelsior’ (Ruh2), ‘Plush’ (Ruh6), and ‘Odessa’ (universal susceptible), were evaluated. Six mated combinations of U. hordei spor...

Pathogenicity tests verifying the behavior of Septoria tritici isolates should be considered as a priority in the selection of resistant wheat materials to this pathogen, since the aggressiveness of each isolate can vary significantly, causing problems in the evaluation and selection of resistant genotypes. The objective of this work was to determine whether physiologic specialization exists am...

onion thrips, thrips tabaci lindeman (thysanoptera: thripidae), is a global pest of onion, Allium cepa l., and the principal vector of iris yellow spot virus (iYsv) that can cause 100% crop losses. the purpose of this study was to evaluate onion cultivars resistant to t. tabaci feeding damage for their reaction to iYsv following exposure to viruliferous t. tabaci in both laboratory and field ex...

Spot blotch caused by the hemibiotrophic pathogen Cochliobolus sativus has been the major yield-reducing factor for barley production during the last decade. Monitoring transcriptional reorganization triggered in response to this fungus is an essential first step for the functional analysis of genes involved in the process. To characterize the defense responses initiated by barley resistant and...

Knowledge of the virulence phenotypes of soybean cyst nematode, Heterodera glycines populations is important in choosing appropriate sources for breeding resistant cultivars and managing the nematode. We investigated races of 59 H. glycines populations collected from 1997 to 1998 and races and HG Types of 94 populations collected in 2002 from soybean fields across southern and central Minnesota...

Globodera rostochiensis population densities and potato root growth were measured in field plots of one susceptible and two resistant potato cultivars. Root growth and nematode densities were estimated from soil samples taken at three depths between plants within the rows, three depths 22.5 cm from the rows, and at two depths midway between rows (furrows). Four weeks after plant emergence (AE),...

Fourteen plant species, including 30 genotypes, were assessed for host suitability to Meloidogyne megadora in a growth room at 20 to 28 degrees C. Host suitability was based on the gall index (GI) and the reproduction factor (Rf):final population density (Pf)/initial population density (Pi). The presence of distinct galling was observed on roots of six plant species, and reproduction occurred o...

Meloidogyne enterolobii is widely considered to be an aggressive root-knot nematode species that is able to reproduce on root-knot nematode-resistant tomato and pepper cultivars. In greenhouse experiments, M. enterolobii isolates 1 and 2 from Switzerland were able to reproduce on tomato cultivars carrying the Mi-1 resistance gene as well as an N-carrying pepper cultivar. Reproduction factors (R...

Part of the first author’s Ph.D. thesis. PROBIOL, UNCuyo, Argentina. ABSTRACT 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 AntárticaINTA, Grano de Oro-Seminis, Valcatorce-INTA and TW-2007 (...