Evaluation of Australian Brassica napus genotypes for resistance to the downy mildew pathogen, Hyaloperonospora parasitica

2008 ◽  
Vol 59 (11) ◽  
pp. 1030 ◽  
Author(s):  
X. T. Ge ◽  
Hua Li ◽  
S. Han ◽  
K. Sivasithamparam ◽  
M. J. Barbetti
Keyword(s):  
Brassica Napus ◽  
Downy Mildew ◽  
Oilseed Rape ◽  
Severe Disease ◽  
Disease Symptoms ◽  
Hyaloperonospora Parasitica ◽  
Spring Type ◽  
High Level ◽  
Resistant Genotypes ◽  
Downy Mildew Disease

Downy mildew, caused by the pathogen Hyaloperonospora parasitica, is a severe disease of oilseed rape (Brassica napus) seedlings in some regions of Australia. Sixty-three cultivars of Australian spring-type oilseed rape were evaluated for their levels of resistance to five isolates of the downy mildew pathogen, using a cotyledon infection test under controlled-environment conditions. A high level of resistance, characterised by the absence of disease symptoms or only the appearance of very sparse sporulation on inoculated cotyledons, was expressed in cvv. Pioneer 45Y77 and Pioneer 46Y78. This is the first study to identify Australian genotypes of oilseed rape highly resistant to H. parasitica. The resistance to H. parasitica identified in this study will not only enable Australian oilseed rape breeders to incorporate resistance to H. parasitica into new cultivars for enhanced resistance to this disease, but will also allow direct deployment of the most highly resistant genotypes identified directly in situations and regions most conducive to the development of severe downy mildew disease.

Segregation of Triazine-Resistant Chloroplasts after Introduction into Winter Type Oilseed Rape (Brassica napus L.) by Protoplast Fusion

1990 ◽  
Vol 45 (5) ◽  
pp. 478-481
Author(s):  
R. Hain ◽  
J. E. Thomzik
Keyword(s):  
Brassica Napus ◽  
Plant Growth ◽  
Protoplast Fusion ◽  
Oilseed Rape ◽  
Field Experiments ◽  
Rflp Analysis ◽  
Winter Oilseed Rape ◽  
Brassica Napus L ◽  
X Irradiation ◽  
Spring Type

Abstract Triazine-resistant chloroplasts of the Canadian spring oilseed rape variety OAC Triton were transferred into four German winter oilseed rape lines and two cultivars of double-low quality by means of protoplast fusion. X-irradiation has been used to reduce the amount of nuclear D N A of the spring type cultivar and to promote cybrid formation. RFLP-analysis showed that some regenerants and their progeny carried both types of chloroplasts. In some instances regenerants and progeny containing mixtures of both chloroplasts not kept under selective conditions lost their triazine-resistant chloroplasts completely during further plant growth. Preliminary results of greenhouse and field experiments indicate that volunteer plants can be eliminated by application of 150-300 g/ha metribuzin (SencorR, Bayer AG) in a stand of triazine-resistant oilseed rape of double-low quality.

scholarly journals Peronospora arborescens Causes Downy Mildew Disease in Commercial Opium Poppy Crops in France

Plant Disease ◽  
2008 ◽  
Vol 92 (5) ◽  
pp. 834-834 ◽  
Author(s):  
M. Montes-Borrego ◽  
F. J. Muñoz-Ledesma ◽  
R. M. Jiménez-Díaz ◽  
B. B. Landa
Keyword(s):  
Downy Mildew ◽  
Phylogenetic Analyses ◽  
Opium Poppy ◽  
Its Sequences ◽  
Maximum Parsimony Analysis ◽  
Disease Symptoms ◽  
Specific Pcr ◽  
Three Samples ◽  
Species Specific ◽  
Downy Mildew Disease

Opium poppy is a strategic crop for the pharmaceutical industry because it is the only source of morphine, codeine, and thebaine alkaloid drugs. Approximately 7,360 ha (average from 2001 through 2007) of opium poppy (Papaver somniferum) are grown annually in France, mainly in the Northern-East (Champagne-Ardenne) and Centre-West (Centre and Poitou-Charentes) regions of the country. This acreage accounts for nearly 5.6% of the legally cultivated opium poppies worldwide. Disease symptoms resembling those of downy mildew (2) have been observed frequently in those opium-poppy-growing areas, especially in the Charente-Maritime, Cher, Loiret, and Loir et Cher departments. Disease symptoms included chlorotic to light yellow lesions on the leaf blade, curling and thickening of affected tissues, and expanding necrotic lesions that coalesced, eventually giving rise to large necrotic areas or death of the entire leaf tissues and the plant. With wet weather or high relative humidity, sporangiophores with sporangia were produced frequently on the abaxial leaf surface and occasionally on the adaxial side. Peronospora arborescens and P. cristata have been demonstrated as causal agents of opium poppy downy mildew disease and both have been reported in Europe (1–3); however, the specific identity causal agent in commercial opium poppy crops in France has not yet been determined. Microscopic observations of affected leaves in symptomatic opium poppy leaves sampled from three commercial fields in Loiret Department revealed dichotomously branching sporangiophores bearing single sporangia and oospores of shape and measurements similar to those reported for P. arborescens and P. cristata (1,3). Sporangia dimensions of P. arborescens and P. cristata overlapped, making it difficult to differentiate between the two species based solely on morphological characters (3). A species-specific PCR assay protocol (2) that differentiated P. arborescens from P. cristata was used to diagnose the pathogen. Also, the sequence of the complete 5.8S ribosomal DNA gene and internal transcribed spacers (ITS) 1 and 2 were determined and maximum parsimony analysis was performed with the Peronospora spp. data set described by Landa et al. (2). Both species-specific PCR and phylogenetic analyses of ITS sequences showed that P. arborescens was the only Peronospora species associated with the three samples of downy-mildew-affected leaves analyzed. Thus, DNA fragments of 545, 594, and 456 bp were amplified using total DNA extracted from the sampled leaves and P2, P3, and P6 primer pairs (2), respectively. ITS sequences of all three samples showed 100% homology (GenBank Accession No. EU295529). Phylogenetic analyses using Neighbor Joining of those sequences placed the infecting Peronospora sp. in a clade (100% support) that included all P. arborescens sequences from the GenBank database with 99.2 to 99.9% homology among sequences (2,3). To our knowledge, this is the first report and molecular evidence that P. arborescens causes downy mildew disease in commercial opium poppy crops in France. References: (1) S. M. Francis. No. 686 in: Descriptions of Pathogenic Fungi and Bacteria. CMI, Kew, Surrey, UK, 1981. (2) B. B. Landa et al. Phytopathology 97:1380, 2007. (3) J. B. Scott et al. Phytopathology 93:752, 2003.

scholarly journals Defence reactions in the apoplastic proteome of oilseed rape (Brassica napus var. napus) attenuate Verticillium longisporum growth but not disease symptoms

2008 ◽  
Vol 8 (1) ◽  
pp. 129 ◽  
Author(s):  
Saskia Floerl ◽  
Christine Druebert ◽  
Andrzej Majcherczyk ◽  
Petr Karlovsky ◽  
Ursula Kues ◽  
...  
Keyword(s):  
Brassica Napus ◽  
Oilseed Rape ◽  
Disease Symptoms ◽  
Verticillium Longisporum ◽  
Defence Reactions

Lipoxygenase activity in fresh, stored, and germinating pearl millet seeds resistant and susceptible to downy mildew disease

1992 ◽  
Vol 70 (10) ◽  
pp. 2028-2031 ◽  
Author(s):  
K. C. Nagarathna ◽  
Sudheer A. Shetty ◽  
H. S. Prakash ◽  
S. G. Bhat ◽  
H. Shekara Shetty
Keyword(s):  
Enzyme Activity ◽  
Key Words ◽  
Downy Mildew ◽  
Pearl Millet ◽  
Lipoxygenase Activity ◽  
High Enzyme ◽  
Pearl Millet Seeds ◽  
Resistant Genotypes ◽  
High Enzyme Activity ◽  
Downy Mildew Disease

Lipoxygenase activity was studied in fresh, stored, and germinating pearl millet seeds of downy mildew resistant and susceptible genotypes. In both fresh and stored seeds, the enzyme activity was greater in resistant genotypes compared with that of the susceptible ones. In seeds stored for a period of 6 months, a significant reduction in the lipoxygenase activity was recorded, the reduction being greater in resistant seeds. Lipoxygenase activity decreased significantly in germinating seedlings of resistant genotypes, whereas it increased significantly in the susceptible seedlings. The high vigour in the resistant seeds of downy mildew resistant genotypes is attributed to their high enzyme activity. Key words: lipoxygenase, pearl millet, downy mildew, resistant, susceptible.

scholarly journals First report of Peronospora variabilis causing downy mildew disease in cañahua (Chenopodium pallidicaule) in Bolivia

2021 ◽  
Author(s):  
Oscar Miguel Rollano-Peñaloza ◽  
Valeria D. Palma-Encinas ◽  
Paola M. Nogales-Ascarrunz ◽  
Susanne Widell ◽  
Allan G. Rasmusson ◽  
...  
Keyword(s):  
Downy Mildew ◽  
Nutritional Value ◽  
Large Scale ◽  
Artificial Infection ◽  
Potential Threat ◽  
Disease Symptoms ◽  
Sequence Identification ◽  
Visual Confirmation ◽  
Andean Highlands ◽  
Downy Mildew Disease

Abstract Cañahua (Chenopodium pallidicaule Aellen) is a semi-domesticated grain cultivated in the Andean highlands for millennia. Cañahua seeds have high nutritional value and it has become attractive because of its high resistance to frost, drought and saline soils. In May 2018, cañahua plants showed symptoms of the downy mildew disease caused by Peronospora variabilis which is known to heavily affect its tetraploid-relative quinoa. Besides the typical symptoms in the plant, visual confirmation of P. variabilis reproductive structures by microscopy was achieved. In order to verify the ability of P. variabilis to infect cañahua, an artificial infection in three cañahua varieties was performed. The three cañahua varieties were infected by P. variabilis and developed downy mildew disease symptoms. The pathogen identity was confirmed by PCR and Sanger sequencing of the PvCox2 and PvITS region. DNA sequence identification confirmed that the P. variabilis that usually infects quinoa can also infect cañahua plants. Therefore, cañahua when grown next to quinoa must be carefully watched for downy mildew disease symptoms because P. variabilis can be a potential threat for future large scale cañahua agriculture.

scholarly journals Yield potential and resistance of corn (Zea mays L.) S5 generation

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
SITI HAFSAH ◽  
BAKHTIAR BAKHTIAR ◽  
NUR ROSLINI ◽  
FIRDAUS FIRDAUS
Keyword(s):  
Downy Mildew ◽  
Block Design ◽  
Yield Potential ◽  
High Yield ◽  
Mass Selection ◽  
Field Station ◽  
Randomized Block Design ◽  
Resistant Genotypes ◽  
Downy Mildew Disease ◽  
High Yield Potential

. Maize S5 generation was obtained and assembled through open pollination, from its parents possessing high yield potential and resistant to downy mildew disease, where the parents were obtained through mass selection.  The objective of this research was to evaluate the yield potential and resistance of maize S5 generation against downy mildew disease.  The research was conducted at Syngenta Seed Indonesia, Kediri Field Station, Kedungmalang Village, Papat District, Kediri Regency, East Java, from May to October 2019.  The research was employed Randomized Block Design (RBD) non Factorial with the only factor observed, 24 genotypes of maize, 5 genotypes for disease resistance assay and 4 genotypes for yield potential assay with 2 replications.  The results showed that there were 5 resistant genotypes, 18ID010125, 18ID010141, 18ID010158, 18ID010134, 18ID010118 and 18ID010122 and 7 potential genotypes to have high yield, 18ID010144, 18ID010123, 18ID006020, 18ID010135, 18ID010125, 18ID007419 and 18ID010148. The results also exhibited 3 genotypes with the highest yield and possessed high resistance against downy mildew (18ID010125, 18ID010123 and 18ID010148).

scholarly journals Potential for Seed Transmission of Verticillium longisporum in Oilseed Rape (Brassica napus)

Plant Disease ◽  
2019 ◽  
Vol 103 (8) ◽  
pp. 1843-1849 ◽  
Author(s):  
Xiaorong Zheng ◽  
Daniel Teshome Lopisso ◽  
Alice Bisola Eseola ◽  
Birger Koopmann ◽  
Andreas von Tiedemann
Keyword(s):  
Brassica Napus ◽  
Oilseed Rape ◽  
Seed Transmission ◽  
Soil Conditions ◽  
Plant Colonization ◽  
Winter Oilseed Rape ◽  
Field Inoculation ◽  
Verticillium Longisporum ◽  
Winter Type ◽  
Spring Type

Verticillium longisporum is a soilborne vascular fungal pathogen that has spread throughout the European oilseed rape cultivation area since the 1980s and was detected in canola fields in Canada in 2014. In a series of greenhouse and field inoculation experiments using V. longisporum-resistant and susceptible cultivars of winter and spring types of oilseed rape, the present study investigated the potential of V. longisporum dissemination by seeds of Brassica napus. Greenhouse inoculation studies with a DsRed-labeled isolate of V. longisporum confirmed the systemic growth of the pathogen from roots to seeds. Further monitoring of plant colonization in the greenhouse with a species-specific real-time polymerase chain reaction assay verified the pathogen growth from roots to stem bases, pods, and seeds in root-inoculated plants. The frequency of recovery of viable colonies of V. longisporum from seeds harvested from greenhouse-grown inoculated plants ranged from 0.08 to 13.3%. The frequency of seed transmission in the greenhouse differed in oilseed rape cultivars varying in susceptibility to V. longisporum. Subsequent studies on transmission of the disease into the offspring revealed that only 1.7 to 2.3% of plants showed disease symptoms as confirmed by the formation of microsclerotia in the stems. Results from field-grown plants differed from the greenhouse studies. The degree of seed transmission in the field was dependent on the crop type. Although only low concentrations of DNA of V. longisporum were detectable in seeds harvested from severely infected winter oilseed rape, significantly greater concentrations of fungal DNA were found in seeds of spring-type oilseed rape, at similar soil conditions and inoculum densities. Correspondingly, plating seeds that were harvested from infected plants on agar yielded viable V. longisporum colonies only from seeds of the spring-type but not of the winter-type plants. Lack of seed infection in the winter-type crop was confirmed in two seasons. Equally, none of the offspring grown from seeds from severely diseased winter oilseed rape plants developed symptoms of Verticillium stem striping. The results suggest that the rate of seed transmission of V. longisporum depends on the degree of plant colonization, which is significantly faster under greenhouse than field conditions and in a spring-sown crop compared with an autumn-sown oilseed rape crop. According to our studies, disease transmission by seeds from European winter oilseed rape production cannot be confirmed.

scholarly journals New sources of sorghum resistant genotypes to downy mildew disease in Uganda

2019 ◽  
Vol 20 (11) ◽  
Author(s):  
Frank Kumi ◽  
Arfang Badji ◽  
Natasha Mwila ◽  
Thomas Odong ◽  
Mildred Ochwo-Ssemakula ◽  
...  
Keyword(s):  
Grain Yield ◽  
Downy Mildew ◽  
Seed Weight ◽  
Plant Disease ◽  
Agricultural Research ◽  
Disease Incidence ◽  
Flowering Plant ◽  
Lattice Design ◽  
Resistant Genotypes ◽  
Downy Mildew Disease

Abstract. Kumi F, Badji A, Mwila N, Odong T, Ochwo-Ssemakula M, Tusiime G, Gibson P, Biruma M, Prom KL, Cuevas HE, Agbahoungba S, Rubaihayo P. 2019. New sources of sorghum resistant genotypes to downy mildew disease in Uganda. Biodiversitas 20: 3391-3397.  Sorghum downy mildew (SDM) disease is still prevalent in Uganda at varying levels of incidence and severity. In this study, a total of 100 sorghum genotypes, five (5) from (U.SA, India, and Sudan) and 95 genotypes from Uganda were evaluated for resistance to downy mildew and other agronomic traits during the second growing season of 2016 (August-December). The experiment was conducted in two locations at Makerere University Agricultural Research Institute at Kabanyolo (MUARIK) and Abi-Zonal Agricultural Research and Development Institute (Abi-ZARDI) research station at Arua. The experimental design used was 10 x 10 alpha lattice design with three replicates. Data were collected on plant disease incidence (PDI), plant disease severity (PDS), area under disease progress curve (AUDPC), days to 50% flowering, plant height, 1000 seed weight, and grain yield. Results for analysis of variance showed highly significant differences (P < 0.001) in genotypes, location, and AUDPC, yield and yield components. Disease incidence varied significantly (P < 0.001) between locations, and Arua recorded highest disease incidence and severity of 80.6 and 2.8, respectively. Results from correlation analysis showed a highly significant (P < 0.001) positive association of downy mildew disease incidence with AUDPC (0.835) which suggests that the severity of SDM disease increased with disease incidence, whiles significant (P < 0.001) negative correlation was recorded for days to 50 % flowering (-0.302), 1000 seed weight (-0.471), and grain yield (-0.585), suggesting that grain yield and yield component decreased significantly with increase in SDM incidence and severity. Two resistant (PI 656061 and PI 533831) and four moderately resistant (E 40, MAKSO 8, PI 655990 and Epuripur) genotypes were identified from this study. These genotypes were recommended for sorghum breeding program against downy mildew disease.

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