scholarly journals Dynamics of bacterial blight disease in resistant and susceptible rice varieties

2022 ◽  
Author(s):  
Jennifer T. Niones ◽  
Ryan T. Sharp ◽  
Dindo King M. Donayre ◽  
Eula Gems M. Oreiro ◽  
Alice E. Milne ◽  
...  
Keyword(s):  
Primary Infection ◽  
Bacterial Blight ◽  
Short Range ◽  
Disease Incidence ◽  
The Philippines ◽  
Resistant Variety ◽  
Rice Varieties ◽  
Infection Efficiency ◽  
Spatial Spread ◽  
Secondary Spread

AbstractBacterial blight (X. oryzae pv. oryzae) is a serious disease in rice across the world. To better control the disease, it is important to understand its epidemiology and how key aspects of this (e.g. infection efficiency, and spatial spread) change according to environment (e.g. local site conditions and season), management, and in particular, variety resistance. To explore this, we analysed data on the disease progress on resistant and susceptible varieties of rice grown at four sites in the Philippines across five seasons using a combination of mechanistic modelling and statistical analysis. Disease incidence was generally lower in the resistant variety. However, we found no evidence that the primary infection efficiency was lower in resistant varieties, suggesting that differences were largely due to reduced secondary spread. Despite secondary spread being attributed to splash dispersal which is exacerbated by wind and rain, the wetter sites of Pila and Victoria in south Luzon tended to have lower infection rates than the drier sites in central Luzon. Likewise, we found spread in the dry season can be substantial and should therefore not be ignored. In fact, we found site to be a greater determinant of the number of infection attempts suggesting that other environmental and management factors had greater effect on the disease than climate. Primary infection was characterised by spatially-random observations of disease incidence. As the season progressed, we observed an emerging short-range (1.6 m–4 m) spatial structure suggesting secondary spread was predominantly short-range, particularly where the resistant variety was grown.

scholarly journals LATTICE THREE-SPECIES MODELS OF THE SPATIAL SPREAD OF RABIES AMONG FOXES

1999 ◽  
Vol 10 (06) ◽  
pp. 1025-1038 ◽  
Author(s):  
A. BENYOUSSEF ◽  
N. BOCCARA ◽  
H. CHAKIB ◽  
H. EZ-ZAHRAOUY
Keyword(s):  
Carrying Capacity ◽  
Short Range ◽  
Lattice Models ◽  
Infection Process ◽  
Spatial Spread ◽  
One Dimensional ◽  
Sense Of Direction ◽  
Speed Of Propagation ◽  
Automata Network ◽  
And Diffusion

Lattice models describing the spatial spread of rabies among foxes are studied. In these models, the fox population is divided into three-species: susceptible (S), infected or incubating (I), and infectious or rabid (R). They are based on the fact that susceptible and incubating foxes are territorial while rabid foxes have lost their sense of direction and move erratically. Two different models are investigated: a one-dimensional coupled-map lattice model, and a two-dimensional automata network model. Both models take into account the short-range character of the infection process and the diffusive motion of rabid foxes. Numerical simulations show how the spatial distribution of rabies, and the speed of propagation of the epizootic front depend upon the carrying capacity of the environment and diffusion of rabid foxes out of their territory.

scholarly journals Reproductive, pathogenic and genotypic characterisation of five Meloidogyne graminicola populations from the Philippines on susceptible and resistant rice varieties

Nematology ◽  
2018 ◽  
Vol 20 (4) ◽  
pp. 299-318
Author(s):  
Ma. Teodora Nadong Cabasan ◽  
Arvind Kumar ◽  
Stéphane Bellafiore ◽  
Dirk De Waele
Keyword(s):  
Phenotypic Variability ◽  
The Philippines ◽  
Growth And Yield ◽  
Oryza Glaberrima ◽  
Rice Varieties ◽  
Single Nucleotide ◽  
Nematode Reproduction ◽  
Rdna Genes ◽  
Meloidogyne Graminicola ◽  
Disease Induction

Summary Five populations of Meloidogyne graminicola isolated from different rice-growing areas in the Philippines were characterised. The populations showed little phenotypic variability of second-stage juveniles and female perineal pattern. Differences in reproduction among M. graminicola populations were not observed on mature resistant Oryza glaberrima varieties ‘TOG5674’, ‘TOG5675’, ‘RAM131’ and ‘CG14’, or on susceptible O. sativa varieties ‘IR64’ and ‘UPLRi-5’. In all infected rice varieties, plant growth and yield-contributing traits showed no differences among the populations. A search on M. graminicola populations from the Philippines for single-nucleotide polymorphism on the sequences of Internal Transcribed Spacer (ITS) of rDNA genes and mtDNA indicated only few points of heteroplasmy. Nematode reproduction and disease induction of the five M. graminicola populations in the Philippines exerted the same level of aggressiveness and virulence. The absence of resistance-breaking populations of M. graminicola is important for the maintenance of durability of resistance to this important rice pathogen.

Comparison of Seed Transmission and Survival of Xanthomonas axonopodis pv. phaseoli and Xanthomonas fuscans subsp. fuscans in Common Bean Seeds

2013 ◽  
Vol 14 (1) ◽  
pp. 41 ◽  
Author(s):  
Y. He ◽  
G. P. Munkvold
Keyword(s):  
Phaseolus Vulgaris ◽  
Common Bean ◽  
Bacterial Blight ◽  
Disease Incidence ◽  
Seed Transmission ◽  
Common Bacterial Blight ◽  
Phaseolus Vulgaris L ◽  
Transmission Frequency ◽  
Xanthomonas Axonopodis ◽  
Seed Health

Xanthomonas axonopodis pv. phaseoli (Smith) Vauterin (Xap) and Xanthomonas fuscans subsp. fuscans Schaad et al. (Xff) cause indistinguishable symptoms known as common bacterial blight of bean (Phaseolus vulgaris L.). These results confirm a higher disease incidence and seed transmission frequency of Xff compared to Xap and reinforce the need for seed health tests that can differentiate the two species. Accepted for publication 21 August 2013. Published 23 September 2013.

scholarly journals Breeding Temperate Japonica Rice Varieties Adaptable to Tropical Regions: Progress and Prospects

Agronomy ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 2253
Author(s):  
Myrish Pacleb ◽  
O-Young Jeong ◽  
Jeom-Sig Lee ◽  
Thelma Padolina ◽  
Rustum Braceros ◽  
...  
Keyword(s):  
The Philippines ◽  
Tropical Region ◽  
Japonica Rice ◽  
Rice Varieties ◽  
Temperate Japonica ◽  
Tropical Regions ◽  
Tropical Environments ◽  
Increasing Demand ◽  
Northeast Asian ◽  
The Tropics

Temperate japonica rice is mainly cultivated in temperate regions. Many temperate japonica varieties have a superior grain quality that is preferred in Northeast Asian countries such as Japan, Korea, and China. The changes in consumers’ preferences in Southeast Asia and Western countries has contributed to increasing the demand for temperate japonica. Most temperate japonica varieties developed in temperate regions typically exhibit extra-early flowering under the short-day conditions in the tropics, which usually results in severely reduced yields. Since 1992, we have been developing temperate japonica varieties that can adapt to tropical environments to meet the increasing demand for temperate japonica rice, having released six varieties in the Philippines. Especially, the yield of one of the temperate japonica varieties, Japonica 7, was comparable to the yields of leading indica varieties in the Philippines. Here, we discuss the current breeding initiatives and future plans for the development of tropical-region-bred temperate japonica rice.

scholarly journals Effect of rejuvenation pruning on the growth, productivity and disease incidence in declining trees of pomegranate (Punica granatum L.) cv. Kandhari Kabuli

2018 ◽  
Vol 10 (1) ◽  
pp. 358-362
Author(s):  
D. P. Sharma ◽  
Niranjan Singh
Keyword(s):  
Bacterial Blight ◽  
Disease Incidence ◽  
Fruit Size ◽  
Punica Granatum ◽  
Fruit Trees ◽  
Fruit Weight ◽  
Shoot Length ◽  
Marketable Yield ◽  
Disease Attack ◽  
Punica Granatum L

Pruning of fruit trees is an important aspect for the improvement of fruit quality and to minimize the pests and disease attack. Pruning was performed in the month of December in seven year old unpruned trees of Punica granatum cv. Knadhdri Kabuli having many interfering branching and a heavy infestation of bacterial blight orchard. The pruning treatments viz., T1: Retention of 15cm fruiting shoot length, T2: Retention of 30cm fruiting shoot length, T3: Retention of 45cm fruiting shoot length, T4: Retention of 60cm fruiting shoot length and T5: control (No heading back and no thinning) plant. The results of the present investigation revealed that among different pruning treatment, the best results in terms of shoot extension (56.34 cm), fruit size (Diameter 9.66 cm and Length 9.65 cm, fruit weight (278.50 g), marketable yield (10.25 kg) and fruit qualities were in fruits from T1 and T2 where retention of 15cm fruiting shoot length respectively and retention of 30cm fruiting shoot length were maintained. However, maximum fruit set (54.73%) was recorded in control, and it decreased with increasing pruning intensity. The pruning treatments also proved beneficial in controlling bacterial blight on fruit (12.86%) and leaf surface (26.60%) to some extent.

scholarly journals Evaluation and Characterization of High Yielding Cassava Mosaic Resistant Variety YTP2

2021 ◽  
pp. 198-208
Author(s):  
L. Pugalendhi ◽  
M. Velmurugan ◽  
P. S. Kavitha ◽  
M. K. Kalarani ◽  
N. Senthil ◽  
...  
Keyword(s):  
Tamil Nadu ◽  
Starch Content ◽  
Disease Incidence ◽  
Mosaic Disease ◽  
Dna Fingerprint ◽  
Cassava Mosaic Disease ◽  
Resistant Variety ◽  
Research Station ◽  
Internodal Length ◽  
New Variety

The cassava variety YTP2 (Me 681) has been developed through selection from Thondamuthur type at Tapioca and Castor Research Station, TNAU, Yethapur. The performance of YTP2 in the Adaptive Research Trial (ART) and On Farm Trial (OFT) in the farmer’s field inferred that this new variety is well adapted to cassava growing districts of Tamil Nadu. In addition to the above, YTP2 was found to be resistant to cassava mosaic disease incidence (CMD). Plants are erect, medium growing and non-branching type and suitable for growing under irrigated and rainfed conditions. The internodal length is shorter and the leaf size is medium with sufficient canopy. The leaves of the plants droop down to reduce the transpiration loss which is more advantageous to overcome or escape from drought and heat stress during summer season. It is a dual purpose variety wherein the tubers contain high starch content which is much favourable for the manufacture of starch, sago and also suited for table purpose. The overall performance of this variety showed higher tuber yield (42.20 t ha-1) and starch content (28.40%) which is 15.94% and 18.20% increase over the check varieties YTP1 and H226 respectively. The results of DNA fingerprint data involving SSR markers (SSRY235, NS169 and NS928) showed that it is genetically distinct from the existing commercial varieties viz., YTP1, H226 and Sree Athulya.

scholarly journals BIOLOGICAL CONTROL OF BANDED LEAF AND SHEATH BLIGHT DISEASE (Rhizoctonia solani KUHN) IN CORN WITH FORMULATED Bacillus subtilis BR23

2016 ◽  
Vol 7 (1) ◽  
pp. 1 ◽  
Author(s):  
Amran Muis ◽  
Arcadio J. Quimio
Keyword(s):  
Bacillus Subtilis ◽  
Seed Germination ◽  
Rhizoctonia Solani ◽  
Seed Treatment ◽  
The Philippines ◽  
Sheath Blight ◽  
Resistant Variety ◽  
Sodium Hypochlorite Solution ◽  
Sheath Blight Disease ◽  
Blight Disease

Rhizoctonia solani Kuhn. causing banded leaf and sheath blight diseases is one of the important fungi of corn world wide. The fungus is commonly controlled by using fungicide because no resistant variety available. The objective of the study was to develop a seed treatment formulation of the selected Bacillus subtilis to control R. solani in corn. The study was conducted in the Department of Plant Pathology, College of Agriculture, University of the Philippines Los Bañòs, College, Laguna from May 2004 to August 2005, using sweet corn var. IPB Supersweet as test plant. Corn seeds were surface sterilized for 10 minutes in 1% sodium hypochlorite solution and 5% ethanol, washed thrice with sterile distilled water and air-dried. The seeds were coated with formulated B. subtilis BR23 and used for several experiments, such as evaluation for their germination and growth in the laboratory, effectively on R. solani in the baked and nonbaked field soil under greenhouse condition, and in the microplots artificially infested with R. solani. The treatment was compared with other standard seed treatment of synthetic fungicides such as captan (10 g per kg seeds) and metalaxyl (10 g per kg seeds). The experiments were designed in a completely random design with three replications. Parameters observed were seed germination, plant height, disease scores, and plant yield. Laboratory formulated B. subtilis BR23 used as seed treatment had no detrimental effects on seed germination and seedling vigor. In microplots artificially infested with a selected highly virulent R. solani, seed treatment with the same formulation increased grain yield by 27% compared to that of the control captan seed treatment with 14.4%. The studies showed the potential of B. subtilis BR23 for commercialization as a seed treatment for the control of banded leaf and sheath blight disease (R. solani) in corn.

scholarly journals The Green Revolution shaped the population structure of the rice pathogen Xanthomonas oryzae pv. oryzae

2019 ◽  
Vol 14 (2) ◽  
pp. 492-505 ◽  
Author(s):  
Ian Lorenzo Quibod ◽  
Genelou Atieza-Grande ◽  
Eula Gems Oreiro ◽  
Denice Palmos ◽  
Marian Hanna Nguyen ◽  
...  
Keyword(s):  
Population Structure ◽  
Plant Pathogens ◽  
Crop Improvement ◽  
Green Revolution ◽  
Agricultural Practices ◽  
The Philippines ◽  
Xanthomonas Oryzae ◽  
Rice Varieties ◽  
Evolutionary Trajectory ◽  
The Impact

Abstract The impact of modern agriculture on the evolutionary trajectory of plant pathogens is a central question for crop sustainability. The Green Revolution replaced traditional rice landraces with high-yielding varieties, creating a uniform selection pressure that allows measuring the effect of such intervention. In this study, we analyzed a unique historical pathogen record to assess the impact of a major resistance gene, Xa4, in the population structure of Xanthomonas oryzae pv. oryzae (Xoo) collected in the Philippines in a span of 40 years. After the deployment of Xa4 in the early 1960s, the emergence of virulent pathogen groups was associated with the increasing adoption of rice varieties carrying Xa4, which reached 80% of the total planted area. Whole genomes analysis of a representative sample suggested six major pathogen groups with distinctive signatures of selection in genes related to secretion system, cell-wall degradation, lipopolysaccharide production, and detoxification of host defense components. Association genetics also suggested that each population might evolve different mechanisms to adapt to Xa4. Interestingly, we found evidence of strong selective sweep affecting several populations in the mid-1980s, suggesting a major bottleneck that coincides with the peak of Xa4 deployment in the archipelago. Our study highlights how modern agricultural practices facilitate the adaptation of pathogens to overcome the effects of standard crop improvement efforts.

scholarly journals High Temperature Enhances the Resistance of Cultivated African Rice, Oryza glaberrima, to Bacterial Blight

Plant Disease ◽  
2016 ◽  
Vol 100 (2) ◽  
pp. 380-387 ◽  
Author(s):  
Gerbert Sylvestre Dossa ◽  
Ricardo Oliva ◽  
Edgar Maiss ◽  
Casiana Vera Cruz ◽  
Kerstin Wydra
Keyword(s):  
High Temperature ◽  
Resistance Genes ◽  
Broad Spectrum ◽  
Host Resistance ◽  
Bacterial Blight ◽  
The Philippines ◽  
Oryza Glaberrima ◽  
Pathogen Invasion ◽  
Broad Spectrum Resistance ◽  
Wide Range

Rice bacterial blight (BB) is caused by Xanthomonas oryzae pv. oryzae and is responsible for substantial yield loss worldwide. Host resistance remains the most feasible control measure. However, pathogen variability leads to the failure of certain resistance genes to control the disease, and climate change with high amplitudes of heat predisposes the host plant to pathogen invasion. Due to pressure in natural selection, landrace species often carry a wide range of unique traits conferring tolerance of stress. Therefore, exploring their genetic background for host resistance could enable the identification of broad-spectrum resistance to combined abiotic and biotic stresses. Nineteen Oryza glaberrima accessions and O. sativa rice variety SUPA were evaluated for BB resistance under high temperature (35 and 31°C day and night, respectively) using 14 X. oryzae pv. oryzae strains originated from the Philippines. Under normal temperature, most of the accessions showed resistance to 9 strains (64.3%) and accession TOG6007 showed broad-spectrum resistance to 12 strains (85.7%). Under high temperature, most accessions showed a reduction in BB disease, whereas, accession TOG5620 showed disease reduction from all the X. oryzae pv. oryzae strains under high temperature. Molecular characterization using gene-based and linked markers for BB resistance genes Xa4, xa5, Xa7, xa13, and Xa21 revealed the susceptible alleles of Xa4, xa5, xa13, and Xa21 in O. glaberrima. However, no allele of Xa7 was detected among O. glaberrima accessions. Our results suggest that O. glaberrima accessions contain a BB resistance different from the Xa gene type. Genome-wide association mapping could be used to identify quantitative trait loci that are associated with BB resistance or combined BB resistance and high-temperature tolerance.

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