Disentangling Peronospora on Papaver: phylogenetics, taxonomy, nomenclature and host range of downy mildew of opium poppy (Papaver somniferum) and related species.

Based on sequence data from ITS rDNA, cox1 and cox2, six Peronospora species are recognised as phylogenetically distinct on various Papaver species. The host ranges of the four already described species P. arborescens, P. argemones, P. cristata and P. meconopsidis are clarified. Based on sequence data and morphology, two new species, P. apula and P. somniferi, are described from Papaver apulum and P. somniferum, respectively. The second Peronospora species parasitizing Papaver somniferum, that was only recently recorded as Peronospora cristata from Tasmania, is shown to represent a distinct taxon, P. meconopsidis, originally described from Meconopsis cambrica. It is shown that P. meconopsidis on Papaver somniferum is also present and widespread in Europe and Asia, but has been overlooked due to confusion with P. somniferi and due to less prominent, localized disease symptoms. Oospores are reported for the first time for P. meconopsidis from Asian collections on Papaver somniferum. Morphological descriptions, illustrations and a key are provided for all described Peronospora species on Papaver. cox1 and cox2 sequence data are confirmed as equally good barcoding loci for reliable Peronospora species identification, whereas ITS rDNA does sometimes not resolve species boundaries. Molecular phylogenetic data reveal high host specificity of Peronospora on Papaver, which has the important phytopathological implication that wild Papaver spp. cannot play any role as primary inoculum source for downy mildew epidemics in cultivated opium poppy crops.

AFLP studies on downy-mildew-resistant and downy-mildew-susceptible genotypes of opium poppy.

Downy mildew (DM) caused by Peronospora arborescens, is a serious disease in opium poppy (Papaver somniferum), which has a world-wide spread. The establishment of DM-resistant cultivars appears to be a sustainable way to control the In this paper, we present the results of a study aimed at the identification of amplified fragment length polymorphism (AFLP) markers for DM-resistance in opium poppy. Three opium poppy genotypes (inbred over about 10 years): Pps-1 (DM-resistant), Jawahar-16 (DM-susceptible) and H-9 (DM-susceptible) were crossed in a diallel manner and the F(1) progeny along with the parents were subjected to AFLP analysis of chloroplast (cp) and nuclear DNA with seven and nine EcoRI / MseI primer combinations, respectively. cpDNA AFLP analysis identified 24 Pps-1 (DM-resistant)-specific unique fragments that were found to be maternally inherited in both the crosses, Pps-1 x Jawahar-16 and Pps-1 x H-9. In the case of nuclear DNA AFLP analysis, it was found that 17 fragments inherited from Pps-1 were common to the reciprocal crosses of both (i) Pps-1 and Jawahar-16 as well as (ii) Pps-1 and H-9. This is the first molecular investigation on the identification of polymorphism between DM-resistant and DM-susceptible opium poppy genotypes and development of DM-resistant opium poppy genotypespecific AFLP markers. These AFLP markers could be used in future genetic studies for analysis of linkage to the downy mildew resistance trait.

Altas diluições de sulfato de zinco sobre o manejo de tripes e rendimento de cebola em sistema orgânico / High dilutions of zinc sulfate on management of thrips and yield of onion in an organic

O cultivo da cebola convencional apresenta alto custo de produção devido ao uso de agroquímicos, e com os consequentes riscos à saúde dos agricultores e contaminação ambiental. A Epagri tem atuado com pesquisa e extensão para a implantação de sistema de produção de cebola orgânico em Santa Catarina. O objetivo deste experimento foi avaliar o efeito de altas diluições de sulfato de zinco sobre a incidência e danos de tripes, maturação fisiológica e rendimento de cebola em sistema orgânico de produção. O estudo foi conduzido durante três anos, 2011, 2012 e 2013, na Epagri, Estação Experimental de Ituporanga, SC. Os tratamentos foram altas diluições de sulfato de zinco em pulverizações foliares nas diluições 6cH, 12cH e 30cH e testemunha sem aplicação. O delineamento experimental foi o de blocos ao caso com quatro repetições. A incidência, danos de tripes, índice de clorofila, produtividade e maturação fisiológica não foram influenciados pelos tratamentos. A conservação pós-colheita de bulbos de cebola com as altas diluições de sulfato de zinco foi ajustada pelo seguinte modelo, em 2011, y= 0,014.x3 -0,626.x2 +5,894.x +56,21 (R2 = 0,56, p= 0,02). (AU)

The cost of onion cultivation in conventional systems in Santa Catarina (SC), Brazil, is high due to the use of agrochemicals, which pose risks to the farmers’ health and contaminate the nvironment. The aim of the present study was to evaluate the effect of high dilutions (HD) of zinc sulfate on the incidence of and damage by thrips, physiological maturation and yield of onion in an organic production system. The study was conducted over three years from 2011to 2013 at Ituporanga Experimental Station, Epagri, SC. Treatments consisted in zinc sulfate HD administered in foliar sprays in dilutions 6cH, 12cH and 30cH and untreated control. The experiment was performed in randomized blocks and four replications. The incidence of and damage by thrips, chlorophyll index and yield were not affected by the treatments. The postharvest storage of onion bulbs with HD of zinc sulfate was fit to the following model in 2011: y= 0.014.x3 -0.626.x2 +5.894.x +56.21 (R2 = 0.56,p= 0.02). (AU)