scholarly journals EVALUATION OF DOWNY MILDEW (HYALOPERONOSPORA BRASSICAE) INFECTION SEVERITY ON DIFFERENT CRUCIFEROUS OILSEED CROPS

2020 ◽  
Vol 2019 (1) ◽  
pp. 329-335
Author(s):  
Eve Runno-Paurson ◽  
Peeter Lääniste ◽  
Viacheslav Eremeev ◽  
Eve Kaurilind ◽  
Hanna Hõrak ◽  
...  
Keyword(s):  
Downy Mildew ◽  
Oilseed Crops ◽  
Hyaloperonospora Brassicae

scholarly journals First Report of Tatsoi Downy Mildew Caused by Hyaloperonospora brassicae in Korea

Plant Disease ◽  
2012 ◽  
Vol 96 (11) ◽  
pp. 1703-1703 ◽  
Author(s):  
Y. J. Choi ◽  
J. Y. Kim ◽  
J. H. Park ◽  
H. D. Shin
Keyword(s):  
Downy Mildew ◽  
Base Pair ◽  
Morphological Difference ◽  
Its Region ◽  
Width Ratio ◽  
Abaxial Surface ◽  
First Report ◽  
Fresh Material ◽  
Hyaloperonospora Brassicae ◽  
Length Width

Tatsoi (Brassica narinosa L.H. Bailey), also called spinach mustard or spoon mustard, is cultivated for edible greens in Asia. In Korea, this plant has recently become popular as a sprout vegetable that is grown to harvestable size in 5 to 6 days. During April 2012, tatsoi seedlings showing typical symptoms of downy mildew were found in plastic greenhouses in Pyeongtaek City of Korea. Infection resulted in chlorotic areas on the leaves with a white mildew developing on the abaxial surface, and finally led to necrosis of the lesions. Affected sprouts were unmarketable and abandoned without harvesting. A sample was deposited in the Korea University herbarium (Accession No. KUS-F26445). Microscopic examination of fresh material was performed under a light microscope. Conidiophores emerging from stomata were hyaline, 270 to 550 × 10 to 25 μm, straight, and monopodially branched in six to eight orders. Ultimate branchlets were mostly in pairs, flexuous, and 15 to 25 μm long. Conidia were hyaline, subglobose, and 20.5 to 26.5 × 19.5 to 24.5 μm with a length/width ratio of 1.05 to 1.20. These characteristics unequivocally indicate the genus Hyaloperonospora (1). Previously H. parasitica (formerly under Peronospora) has been considered a causal agent of downy mildew on tatsoi (2,4), but the present Korean accession is morphologically distinct from the former species by possessing subglobose conidia with a low length/width ratio. To confirm this morphological difference, amplification and sequencing of the internal transcribed spacer (ITS) region of rDNA of the Korean specimen were performed using procedures outlined by Göker et al. (3). The resulting 874-bp sequence of the region was deposited in GenBank (Accession No. JX401551). A comparison with the ITS sequences available in the GenBank database revealed that it was identical to Hyaloperonospora brassicae found on Brassica oleracea var. italica (EU137726), and showed only one base pair substitution compared to pathogens from B. rapa ssp. pekinensis (JF975613) and B. napus spp. napus (EU049248), but is significantly different from H. parasitica on Capsella bursa-pastoris (AY210988) with a base-pair dissimilarity of about 13%. Therefore, the pathogen found in Korea was confirmed to be H. brassicae. Pathogenicity was demonstrated by shaking diseased leaves onto the leaves of healthy tatsoi seedlings, incubating the plants in a dew chamber at 20°C for 24 h, and then maintaining them in a greenhouse (22 to 26°C). After 3 days, inoculated plants developed downy mildew symptoms from which identical fungi were observed, thus fulfilling Koch's postulates. Control plants treated with sterile water did not develop any symptoms or signs of downy mildew. This is the first report of a downy mildew on tatsoi in Korea, although it has been found in China (2) and Japan (4). To our knowledge, there is no record of tatsoi downy mildew outside East Asia (2,4). References: (1) O. Constantinescu and J. Fatehi. Nova Hedwigia 74:291, 2002. (2) D. F. Farr and A. Y. Rossman. Fungal Databases, Systematic Mycology and Microbiology Laboratory, ARS, USDA. Retrieved from http://nt.ars-grin.gov/fungaldatabases/ July 18, 2012. (3) M. Göker et al. Mycol. Res. 113:308, 2009. (4) M. Satou et al. Annu. Rep. Soc. Plant Protect. N. Jpn. 50:62, 1999.

scholarly journals Comparing Cotyledon, Leaf and Root Resistance To Downy Mildew in Radish (Raphanus Sativus L.)

2021 ◽  
Author(s):  
Paula S. Coelho ◽  
Luisa Valério ◽  
António A. Monteiro
Keyword(s):  
Downy Mildew ◽  
Post Inoculation ◽  
Plant Organ ◽  
Radish Root ◽  
Raphanus Sativus L ◽  
Hyaloperonospora Brassicae ◽  
Leaves And Roots ◽  
Edible Root ◽  
Root Resistance ◽  
Brassicaceae Family

Abstract Radish downy mildew (DM) is a disease caused by the oomycete Hyaloperonospora brassicae f. sp. raphani and it is a serious problem in radish production, an edible root vegetable crop of the Brassicaceae family. The objective of this research was to assess radish germplasm for DM resistance and to evaluate the response of different radish organs to the disease. Cotyledons, true-leaves and roots of 44 radish accessions were inoculated with H. brassicae isolates under controlled conditions. The cotyledons were individually evaluated 7dpi (days post-inoculation), and the leaves and roots 12dpi. DM symptoms varied with the radish genotype and plant organ analysed. Thirty-five resistant and partially resistant accessions were identified and are promising sources to DM. A significant correlation was observed between cotyledon and leaf (1st and 2nd leaves) DM resistance, but no correlation was found between the resistance of cotyledons or true-leaves and roots. Cotyledon and leaf response cannot be used to predict radish root resistance. However, cotyledon resistance has its own value because non-infected cotyledons will act as a barrier to slow disease progression to true-leaves and roots.

ALLOCATION OF SOURCES AND DONORS OF ECONOMICALLY VALUABLE TRAITS FROM THE COLLECTION MATERIAL OF CUCUMBER TO CREATE HIGHLY PRODUCTIVE VARIETIES AND HYBRIDS

1970 ◽  
pp. 45-49
Author(s):  
N. V. Kulyakina ◽  
G. A. Kuzmitskaya ◽  
T. K. Yurechko
Keyword(s):  
Genetic Resources ◽  
Downy Mildew ◽  
Geographical Origin ◽  
Plant Genetic Resources ◽  
Eastern Region ◽  
Biotic And Abiotic Stress ◽  
Climate Conditions ◽  
Damage Degree ◽  
Economically Valuable Traits ◽  
Far Eastern

The downy mildew (peronosporosis) is the most dangerous and harmful cucumber disease in the Far-Eastern region. Its harmfulness is the highest during the period of flowering – fruiting, because it may completely ruin the cucumber plants both in open and protected ground. Use of cucumber sorts with effective genes that are resistant to the disease is the most efficient way to fight cucumber peronosporosis. In this connection the publication adduces the facts of study the sorts and hybrids of different ecological and geographical origin from the genetic resources collection of the N.I. Vavilov All-Russian Institute of Plant Genetic Resources (VIR) in comparison with three zoned sorts of DV NIISH selection – Mig, Khabar, Amurchonok. The aim of researches – to identify the sort samples cucumber according to the main economically valuable traits and also to the degree resistance of genetypes to the main disease of the culture in the region – downy mildew (peronosporosis), for allow to select the source material for the creation of sorts and hybrids, highly productive and resistant to biotic and abiotic stress environmental factors in the monsoon climate conditions of Khabarovsk region. The perspective genetypes having both the resistance to the diseases and productivity are not revealed as a result of the evaluation of the collection of cucumber samples according to their susceptibility by fungus diseases and productivity. Slavyanskiy (Belarus) is more resistant to peronosporosis, especially in 2016 year conditions, although it was inferior to the damage degree of disease to the zoned sorts – Mig, Khabar, Amurchonok. This perspective sample is planned to be used as a source of donors of the main economically valuable traits in a further selective work.

Symptoms Development as Tools to Differentiate Dorizontal Resistance in Sunflower

Agrotek ◽  
2018 ◽  
Vol 2 (6) ◽  
Author(s):  
Cipta Meliala ◽  
Felicity Fear ◽  
Denis Tourvieille de Labrouhe
Keyword(s):  
Downy Mildew ◽  
Natural Infection ◽  
Resistance Mechanism ◽  
Good Method ◽  
Vegetative Stage ◽  
Horizontal Resistance ◽  
Symptom Development ◽  
Plasmopara Halstedii ◽  
Controlled Conditions ◽  
Symptom Progression

Downy mildew symptoms caused by Plasmopara halstedii encountered in sunflower plantation are varied. This variation may be related to the resistance mechanism presented by plant to the invasion of the fungus. Our objectives were firstly is to evaluate symptom development after fungus race 710 inoculation on some vegetative stage of susceptible hybrid. Second objective is to evaluate the reaction some sunflower genotypes after fungus inoculation. The study was conducted under controlled conditions or under netting cages in the field. The development of downy mildew symptoms were affected by all factors studied. Shoot inoculation may present a good method to produce downy mildew symptom similar to the natural infection. Downy mildew symptom progression may be used to screen a genotype with a horizontal resistance.

Peronosporales of Skadovsky Zvenigorod Biological Station (Moscow Region)

2018 ◽  
Vol 52 (1) ◽  
pp. 91-100
Author(s):  
E. Yu. Blagoveshchenskaya
Keyword(s):  
Downy Mildew ◽  
European Part ◽  
Moscow Region ◽  
State University ◽  
Biological Station ◽  
Annotated List ◽  
European Part Of Russia ◽  
First Time ◽  
Moscow State University

The paper provides the results of seven-year study of downy mildew on Skadovsky Zvenigorod Biological Station of Moscow State University (ZBS MSU, Moscow Region). A total of 29 species of Peronosporales (Oomycota) were revealed during the study. An annotated list of species is presented, among them Peronospora anemones is recorded for the first time for Russia, P. chelidonii and P. stachydis are new for the European part of Russia, 8 species are new for the Moscow Region.

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