Conclusions: During the seedling stage, more than 10 kg of bare seed ha-1 are required to reach the minimum recommended number of plants (250 pl m-2). Even when data indicates that as little as 5 kg ha-1 of bare seed are enough to reduce the time it takes the stand to reach the threshold of minimal plant density by ~400 days, increasing sowing rate to >10 kg ha-1 appears to be necessary to reduce weed competition and the costs associated with herbicides.

Abstract: Predicting the occurrence of the critical period for soybean?s yield determination is important for farmers to decide on variety and sowing date with the objective to expose this period (during which yield is mainly determined) to the best environmental conditions

CRONOTRIGO© 2.0 se inició en el marco de un proyecto financiado por PROCISUR en el que están involucrados grupos de investigación de Argentina, Paraguay,Uruguay y Chile. El modelo CRONOTRIGO© 2.0 ya puede utilizarse en Argentina en el dominio http://cronotrigo.agro.uba.ar/ y para este año (2021) se expandirá al resto de los países involucrados en el proyecto PROCISUR (coordinado por la Dra. Fernanda G. González, EEA INTA Pergamino).

CRONOTRIGO© 2.0 se inició en el marco de un proyecto financiado por PROCISUR en el que están involucrados grupos de investigación de Argentina, Paraguay,Uruguay y Chile. El modelo CRONOTRIGO© 2.0 ya puede utilizarse en Argentina en el dominio http://cronotrigo.agro.uba.ar/ y para este año (2021) se expandirá al resto de los países involucrados en el proyecto PROCISUR (coordinado por la Dra. Fernanda G. González, EEA INTA Pergamino).

Abstract: Silicon (Si) has an important role in mitigating diverse biotic and abiotic stresses in plants, mainly via the silicification of plant tissues. Environmental changes such as atmospheric CO2 concentrations may affect grass Si concentrations which, in turn, can alter herbivore performance. We recently demonstrated that pre?industrial atmospheric CO2 increased Si accumulation in Brachypodium distachyon grass, yet the patterns of Si deposition in leaves and whether this affects insect herbivore performance remains unknown.

Abstract:Juncus microcephalus plants showing symptoms of root-knot nematode infestation were observed in the municipality of Agudo, Rio Grande do Sul state, Brazil. Based on morphological observation, esterase phenotypes, and molecular analyses of rDNA-ITS and D2- D3 regions of 28S rDNA, the causal agent of the observed symptoms was identified as Meloidogyne graminicola. Pathogenicity of M. graminicola was confirmed by fulfilling modified Koch?s postulates. To our knowledge, this is the first report of M. graminicola in J. microcephalus in Rio Grande do Sul State, Brazil.

ABSTRACT. Citrus psorosis virus (CPsV) is the causal agent of psorosis, an important disease of citrus. Sanitary and certification programmes helped reduce disease damage caused by psorosis and other graft‐transmissible diseases in many citrus‐growing regions. For quarantine and certification programmes, most of these diseases are currently diagnosed using biological indexing (BI) on sensitive indicator plants.

ABSTRACT. Onion downy mildew (DM) caused by Peronospora destructor is a very destructive leaf disease. Genetic resistance is an economic and environmentally friendly way of disease control. In this research, the segregation of DM resistance was analysed in six offspring from crosses between national cultivars and the cv. ?Regia?, a partial resistance source. F1 plants were self-fertilised, and F1S1 derived progenies were evaluated. The segregations in DM severity were skewed towards susceptibility, with transgressive segregation in five of six progenies.