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Journal articles on the topic 'Seedling blast'
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1
Chen, Pingli, Guanjun Gao, Guangming Lou, et al. "Improvement of Rice Blast Resistance in TGMS Line HD9802S through Optimized Anther Culture and Molecular Marker-Assisted Selection." International Journal of Molecular Sciences 24, no. 19 (2023): 14446. http://dx.doi.org/10.3390/ijms241914446.
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Rice blast caused by Magnaporthe oryzae is one of the most serious rice diseases worldwide. The early indica rice thermosensitive genic male sterile (TGMS) line HD9802S has the characteristics of stable fertility, reproducibility, a high outcrossing rate, excellent rice quality, and strong combining ability. However, this line exhibits poor blast resistance and is highly susceptible to leaf and neck blasts. In this study, backcross introduction, molecular marker-assisted selection, gene chipping, anther culture, and resistance identification in the field were used to introduce the broad-spectrum blast-resistance gene R6 into HD9802S to improve its rice blast resistance. Six induction media were prepared by varying the content of each component in the culture medium. Murashige and Skoog’s medium with 3 mg/L 2,4-dichlorophenoxyacetic acid, 2 mg/L 1-naphthaleneacetic acid, and 1 mg/L kinetin and N6 medium with 800 mg/L casein hydrolysate, 600 mg/L proline, and 500 mg/L glutamine could improve the callus induction rate and have a higher green seedling rate and a lower white seedling rate. Compared to HD9802S, two doubled haploid lines containing R6 with stable fertility showed significantly enhanced resistance to rice blast and no significant difference in spikelet number per panicle, 1000-grain weight, or grain shape. Our findings highlight a rapid and effective method for improving rice blast resistance in TGMS lines.
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Bhatta, Anjan, Anuj Sharma, Puja Gautam, et al. "Resistant and susceptible response of finger millet to seedling blast (Pyricularia grisea sacc.)." International Journal of Information Research and Review 4, no. 12 (2017): 4804–9. https://doi.org/10.5281/zenodo.6970365.
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25 accessions of finger millet, 20 from Parbat and 5 from Khotang, were experimented at nursery stage in randomized complete block design at Institute of Agriculture and Animal Science (IAAS), Rampur, Chitwan from July 2015 to September 2015 to identify the resistance response against seedling blast. Inoculation was done by piling up of diseased leaves in trenches between the beds. Ten plants from each plot were tagged randomly and disease severity was assessed by scoring on a 0-9 scale for 4 times at 6 days interval from 22 days after sowing (DAS) onwards. Dry root and shoot weights of the tagged plants were measured on 43 DAS to access plant biomass. Three accessions failed to geminate. Final disease severity was found to be highest in NGRC05161 (58.5%) and lowest in NGRC05146 (39.3%). Based on total AUDPC, NGRC05143 (664) was found to be least susceptible to seedling blast while NGRC05164 (895) was most susceptible. Disease severity increased up to 34 DAS and decreased thereafter. AUDPC showed continuous increase in decreasing rate. Shoot weight was found to be negatively correlated to mean AUDPC whereas root-to-shoot ratio was positively correlated. Three accessions were categorized as moderately susceptible and rest as susceptible to seedling blast. Accessions collected from Khotang were in general more susceptible to blast than those from Parbat district.
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Gomes, Delineide Pereira, Valterley Soares Rocha, João Romero do Amaral Santos de Carvalho Rocha, Olinto Liparini Pereira, and Moacil Alves de Souza. "Potential of transmission of Pyricularia graminis-tritici from plant to seed and from seed to seedling in wheat genotypes with different degrees of blast resistance." Journal of Seed Science 40, no. 1 (2018): 16–24. http://dx.doi.org/10.1590/2317-1545v40n1181833.
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Abstract: Transmission studies of Pyricularia graminis-tritici by wheat seed can help establishing pathogen tolerance standards in crops. Four genotypes, each one with different responses to blast, were inoculated with five volumes of fungal suspension (1,5x105 spores.mL-1), in order to obtain 0, 5, 10, 20 and 30% of plants inoculated in the experimental unit. The potential of transmission of P. graminis-tritici from plant to seed was evaluated by the incidence of the fungus in the seeds produced. Under controlled conditions, the transmission rate of the fungus from seed to seedling was evaluated. Blast incidence in field allowed a high incidence of P. graminis-tritici in the seeds, especially in the genotypes considered susceptible. The transmission of fungus from the seeds to seedlings occurred 7, 14 and 21 days after sowing, at low rates. There was a relationship between the presence of blast in field and the incidence of P. graminis-tritici in seeds produced by the genotypes BRS 264, VI 98053, CD 116 and CD 104. Inoculation of 5, 10, 20 and 30% of plants with fungus can generate a high incidence of the pathogen in field and in the seeds produced, but it doesn`t guarantee a high transmission rate from seed to seedling, which is low under controlled conditions.
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Ghimire, Krishna Hari, Hira Kaji Manandhar, Madhav Prasad Pandey, et al. "Multi-Environment Screening of Nepalese Finger Millet Landraces against Blast Disease [Pyricularia grisea (Cooke) Sacc.)]." Journal of Nepal Agricultural Research Council 8 (May 9, 2022): 35–52. http://dx.doi.org/10.3126/jnarc.v8i.44874.
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Three hundred finger millet genotypes (295 landraces from 54 districts and five released varieties) were evaluated for leaf, finger, and neck blast resistance under natural epiphytotic conditions across three hill locations in Nepal, namely Kabre, Dolakha (1740m); Vijaynagar, Jumla (2350 m); and Khumaltar, Lalitpur (1360 m) during the summer seasons of 2017 and 2018. The highest incidence of leaf, neck, and finger blast was observed at Lalitpur, followed by Dolakha and Jumla, whereas the overall disease incidence was higher in 2018 compared to 2017. Combined analysis over environments revealed non-significant differences among accessions for leaf blast, but the difference was highly significant for neck and finger blast. Correlation analysis suggested that there was a strong positive correlation between neck blast and finger blast (r = 0.71), leaf blast (seedling stage) and neck blast (r = 0.68), and leaf blast (seedling stage) and finger blast (r = 0.58) diseases. Among 300 accessions, 95 had lower scores for finger blast, 30 for neck blast, and 74 for leaf blast than the score of Kabre Kodo-2, the latest released variety in Nepal. Genotypes NGRC04798, NGRC03478, NGRC05765, NGRC03539, NGRC06484, NGRC01458, NGRC01495 and NGRC01597 were found the resistant genotypes for finger blast (2.1-2.3) and neck blast (1.5-2.3) based on pooled mean scores. This study shows the variable reactions of finger millet genotypes against blast disease in various environments and reports the promising landraces having field resistance to leaf, finger, and neck blast, which ultimately serve as important donors for blast resistance in finger millet breeding.
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Dissanayaka, D. M. H. R., M. D. Pabasara, G. K. S. N. Gajanayake, W. A. M. Daundasekera, and H. A. C. K. Ariyarathna. "A case report on Blast disease in Rice and Finger millet in Sri Lanka." Ceylon Journal of Science 53, no. 2 (2024): 193–96. http://dx.doi.org/10.4038/cjs.v53i2.8399.
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Blast disease caused by Magnaporthe sp. is one of the most destructive diseases in cereal crops. Disease infection was studied in farmer fields. Field data was recorded and further information was gathered by interviewing the farmers and agrarian extension officers. Blast infections were assessed in the fields using a standard evaluation system for rice (SES IRRI, 1996). Although symptoms were not observed in seedlings when mature rice fields were infected farmers experienced 100% yield loss. There were no or few leaf symptoms in blast infected mature rice fields yet neck infections were scored as 9 in SES. Unlike rice, leaf blast at seedling stage caused economic losses in finger millet. Mature finger millet fields were susceptible to neck and finger blast. Due to rapid disease development curative fungicide treatment was ineffective in controlling blast. Farmers reported sudden changes in the weather during infections whereby gloomy weather caused a spike in humidity and low temperatures that coincided with the infection. Host susceptibility window synchronized with conducive environments result in severe blast infections therefore, blast disease management needs a coordinated effort and system level interventions whereby control measures and use of resistant germplasm can be combined with climate-based disease predictions to increase the efficiency of disease control.
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Loi, Nguyen Thi Thanh, Nguyen Tran Mai Anh, Ho Manh Tuong, et al. "Biocontrol potentiality of <i>Burkholderia vietnamiensis</i> nrv12 against the rice blast fungus <i>magnaporthe oryzae</i>." Vietnam Journal of Biotechnology 22, no. 2 (2024): 341–56. http://dx.doi.org/10.15625/vjbt-20167.
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Rice blast disease, caused by the pathogenic fungus Magnaporthe oryzae, is a widespread infection leading to serious crop loss worldwide. In order to achieve sustainable agriculture, root-associated bacteria have been applied to manage fungal diseases and promote growth. The present study aimed to evaluate in vitro the growth-promoting ability and in vivo biocontrol activity against M. oryzae of rice rhizosphere bacterium. Out of sixty-eight isolates recovered from the rhizosphere of blast-infected rice plants, isolate NRV12 exhibited the highest antifungal activity against M. oryzae SH, with an inhibition percentage of 72.7±3.44%. By analysis of 16S rRNA sequence associated with morphology, physiological and biochemical tests, the strain was identified as Burkholderia vietnamiensis. In addition, NRV12 produced hydrolytic enzymes (amylase, cellulase, protease), indole acetic acid (IAA), exhibited nitrogen-fixing potential and the ability to solubilize phosphate and zinc. Innoculation with NRV12 significantly promoted in vivo rice seedling growth to 23.3% as compared to the non-bacteria-treated seedlings. Importantly, infected rice seedlings treated with NRV12 led to a 40% disease reduction in rice blast. These findings suggest that NRV12 is a valuable and promising isolate with biocontrol potential against rice blast caused by M. oryzae.
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Gerema, Geleta, Girma Mengistu, Megersa Kebede, et al. "Seedling and adult plant resistance to Pyricularia oryzae in Ethiopian rice cultivars." Acta Universitatis Sapientiae, Agriculture and Environment 12, no. 1 (2020): 45–57. http://dx.doi.org/10.2478/ausae-2020-0004.
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Abstract Two separate experiments were done for seedling and adult resistance in rice varieties against blast. Each experiment consists of 20 varieties and is evaluated under artificial inoculation with blast. The result of the study confirmed that NERICA varieties have shown low disease infection at the seedling stage whereas the varieties Chewaka and Edget have shown adult plant resistance. Severe yield reduction and highly diseased grain were obtained from Superica-1, which is highly susceptible at adult plant stage. In contrast, the maximum grain yield was obtained from the Chewaka and Edget varieties, these having a high level of adult resistance. Therefore, Chewaka and Edget are promising candidates for utilization in yield and blast resistance in rice improvement.
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Gerema, Geleta, Girma Mengistu, Megersa Kebede, et al. "Seedling and adult plant resistance to Pyricularia oryzae in Ethiopian rice cultivars." Acta Universitatis Sapientiae, Agriculture and Environment 12, no. 1 (2020): 45–57. http://dx.doi.org/10.2478/ausae-2020-0004.
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AbstractTwo separate experiments were done for seedling and adult resistance in rice varieties against blast. Each experiment consists of 20 varieties and is evaluated under artificial inoculation with blast. The result of the study confirmed that NERICA varieties have shown low disease infection at the seedling stage whereas the varieties Chewaka and Edget have shown adult plant resistance. Severe yield reduction and highly diseased grain were obtained from Superica-1, which is highly susceptible at adult plant stage. In contrast, the maximum grain yield was obtained from the Chewaka and Edget varieties, these having a high level of adult resistance. Therefore, Chewaka and Edget are promising candidates for utilization in yield and blast resistance in rice improvement.
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Guerber, C., and D. O. TeBeest. "Infection of Rice Seed Grown in Arkansas by Pyricularia grisea and Transmission to Seedlings in the Field." Plant Disease 90, no. 2 (2006): 170–76. http://dx.doi.org/10.1094/pd-90-0170.
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Rice blast, caused by Pyricularia grisea, is an important and serious disease of rice (Oryza sativa) in the southeastern United States. The disease sporadically reaches epidemic proportions on susceptible cultivars within fields and over large areas within Arkansas. The main overwintering sources of inoculum reportedly include infected rice stubble, related host species, and infected seed. The objectives of the research were to (i) determine whether rice seed grown in Arkansas were infected with P. grisea, (ii) investigate the relationship between seed infection and seedling disease, and (iii) determine if planting naturally infected seed could lead to the subsequent development of rice blast on seedlings in the field. The results of seed assays showed that P. grisea was detected in samples of foundation, certified, and production seed. Estimated levels of infection by P. grisea of rice seed from 66 samples of rice seed grown in Arkansas ranged from 0 to 10.5%. Planting infected seed in the greenhouse and the field resulted in seedling infection. Planting naturally infected seed may result in disease development (i) from seedlings grown from infected seed planted beneath the soil surface, (ii) from seedlings grown from germinating seed left on the soil surface, (iii) from seed coats, or (iv) from nongerminated seed left on the soil surface after planting. Additional research is necessary to establish the mechanisms of infection of seedlings and to establish disease thresholds for this important fungal pathogen of rice.
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Yuan, Hongliang, Jingya Qian, Chunwei Wang, et al. "Exogenous Melatonin Enhances Rice Blast Disease Resistance by Promoting Seedling Growth and Antioxidant Defense in Rice." International Journal of Molecular Sciences 26, no. 3 (2025): 1171. https://doi.org/10.3390/ijms26031171.
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In order to analyze the physiological regulation mechanisms associated with exogenous melatonin on rice blast, this study treated rice seedlings with different concentrations of melatonin (0, 20, 100, and 500 µmol/L) in order to investigate the growth characteristics, root morphology, superoxide dismutase (SOD) activity, peroxidase (POD) activity, catalase (CAT) activity, malondialdehyde (MDA) content, hydrogen peroxide (H2O2) content, and soluble protein content of rice seedlings. The results indicated that 100 µmol/L of melatonin exhibited a significant effect, improving the growth and antioxidant capacity of rice seedlings under rice blast fungus infection. The disease resistance level of rice seedlings against rice blast significantly decreased by 31.58% when compared to the 0 µmol/L melatonin treatment, while the plant height, stem base width, plant leaf area, total root length, aboveground dry weight, aboveground fresh weight, and underground fresh weight significantly increased by 8.72% to 91.38%. Treatment with 100 µmol/L of melatonin significantly increased catalase activities and soluble protein content, with respective increases of 94.99% and 31.14%. Simultaneously, the contents of malondialdehyde and hydrogen peroxide significantly decreased, reaching 18.65% and 38.87%, respectively. The gray relational grade analysis indicated that hydrogen peroxide content and resistance level exhibit the highest gray relational grades with melatonin concentration and, so, can be used to evaluate the effect of melatonin on the severity of rice blast fungus infection. Furthermore, the membership function analysis revealed that the 100 µmol/L melatonin treatment had the highest membership function value, indicating a significant improvement in the resistance of rice seedlings to rice blast disease. In conclusion, 100 µmol/L of melatonin enhances the resistance of rice seedlings to rice blast disease through promoting their growth and strengthening their antioxidant defenses. This study provides new insights into the tolerance mechanisms of rice seedlings against rice blast disease.
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Wu, Yunyu, Yu Chen, Cunhong Pan, et al. "Development and Evaluation of Near-Isogenic Lines with Different Blast Resistance Alleles at the Piz Locus in japonica Rice from the Lower Region of the Yangtze River, China." Plant Disease 101, no. 7 (2017): 1283–91. http://dx.doi.org/10.1094/pdis-12-16-1855-re.
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Rice blast, caused by Magnaporthe oryzae, threatens rice production in most of the rice-growing areas in China, especially in regions that have grown Oryza sativa subsp. japonica in recent years. The use of resistance genes is the most effective and economical approach for blast control. In our study, a set of six near-isogenic lines (NIL) were developed by introgression of six resistance alleles of the Piz locus (Pi2, Pigm, Pi40, Pi9, Piz, and Pizt) into a blast-susceptible, high-yielding, high-quality japonica ‘07GY31’ via marker-assisted backcross breeding. Artificial inoculation using 144 M. oryzae isolates collected from the lower region of the Yangtze River, China, revealed that most of the NIL, including NIL-Pi2, NIL-Pigm, NIL-Pi40, NIL-Pi9, and NIL-Pizt, exhibited broad-spectrum resistance against rice blast at the seedling stage, with resistance frequencies (RF) of 93.06 to 98.61%. NIL-Piz was an exception, with an RF of 21.53%, which was slightly higher than the recurrent parent 07GY31. NIL-Pi40 and NIL-Pigm had broad-spectrum resistance (RF of 93.33 and 71.67%, respectively) at the heading stage following inoculation of 60 isolates of M. oryzae. Field trials with artificial inoculation at the seedling and heading stage showed that NIL-Pigm and NIL-Pi40 were highly resistant in four locations under high disease pressure. NIL-Pizt showed effective resistance in three locations from Zhejiang and Jiangsu Provinces. This study shows that O. sativa subsp. japonica alleles of the Piz locus confer resistance to M. oryzae, and provides an effective method to enhance seedling and panicle blast resistance in rice plants in the lower region of the Yangtze River, China.
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Cruz, Christian D., William W. Bockus, James P. Stack, et al. "Preliminary Assessment of Resistance Among U.S. Wheat Cultivars to the Triticum Pathotype of Magnaporthe oryzae." Plant Disease 96, no. 10 (2012): 1501–5. http://dx.doi.org/10.1094/pdis-11-11-0944-re.
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Magnaporthe oryzae is the causal agent of blast disease on several graminaceous plants. The M. oryzae population causing wheat blast has not been officially reported outside South America. Wheat production in the United States is at risk to this pathogen if it is introduced and established. Proactive testing of U.S. wheat cultivars for their reaction to blast and identification of resistance resources is crucial due to the national and global importance of the U.S. wheat industry. In this preliminary study, the phenotypic reaction of 85 U.S. wheat cultivars to M. oryzae (Triticum pathotype) was determined. Although there was a significant correlation in the reaction to blast at the seedling and adult plant stages, only 57% of the head reaction was explained by the seedling reaction. Because of the importance of disease development at the head stage in the field, assessment of all 85 cultivars occurred at the head stage. Among cultivars tested, a continuum in severity to head blast was observed; cultivars Everest and Karl 92 were highly susceptible with more than 90% disease severity, while cultivars Postrock, JackPot, Overley, Jagalene, Jagger, and Santa Fe showed less than 3% infection. No evidence of the presence of physiological races among isolates T-7, T-12, T-22, and T-25 was found.
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Gao, Peng, Mingyou Li, Xiaoqiu Wang, et al. "Identification of Elite R-Gene Combinations against Blast Disease in Geng Rice Varieties." International Journal of Molecular Sciences 24, no. 4 (2023): 3984. http://dx.doi.org/10.3390/ijms24043984.
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Rice blast, caused by the Magnaporthe oryzae fungus, is one of the most devastating rice diseases worldwide. Developing resistant varieties by pyramiding different blast resistance (R) genes is an effective approach to control the disease. However, due to complex interactions among R genes and crop genetic backgrounds, different R-gene combinations may have varying effects on resistance. Here, we report the identification of two core R-gene combinations that will benefit the improvement of Geng (Japonica) rice blast resistance. We first evaluated 68 Geng rice cultivars at seedling stage by challenging with 58 M. oryzae isolates. To evaluate panicle blast resistance, we inoculated 190 Geng rice cultivars at boosting stage with five groups of mixed conidial suspensions (MCSs), with each containing 5–6 isolates. More than 60% cultivars displayed moderate or lower levels of susceptibility to panicle blast against the five MCSs. Most cultivars contained two to six R genes detected by the functional markers corresponding to 18 known R genes. Through multinomial logistics regression analysis, we found that Pi-zt, Pita, Pi3/5/I, and Pikh loci contributed significantly to seedling blast resistance, and Pita, Pi3/5/i, Pia, and Pit contributed significantly to panicle blast resistance. For gene combinations, Pita+Pi3/5/i and Pita+Pia yielded more stable pyramiding effects on panicle blast resistance against all five MCSs and were designated as core R-gene combinations. Up to 51.6% Geng cultivars in the Jiangsu area contained Pita, but less than 30% harbored either Pia or Pi3/5/i, leading to less cultivars containing Pita+Pia (15.8%) or Pita+Pi3/5/i (5.8%). Only a few varieties simultaneously contained Pia and Pi3/5/i, implying the opportunity to use hybrid breeding procedures to efficiently generate varieties with either Pita+Pia or Pita+Pi3/5/i. This study provides valuable information for breeders to develop Geng rice cultivars with high resistance to blast, especially panicle blast.
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Maciel, João L. Nunes, Paulo C. Ceresini, Vanina L. Castroagudin, Marcelo Zala, Gerrit H. J. Kema, and Bruce A. McDonald. "Population Structure and Pathotype Diversity of the Wheat Blast Pathogen Magnaporthe oryzae 25 Years After Its Emergence in Brazil." Phytopathology® 104, no. 1 (2014): 95–107. http://dx.doi.org/10.1094/phyto-11-12-0294-r.
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Since its first report in Brazil in 1985, wheat blast, caused by Magnaporthe oryzae (anamorph: Pyricularia oryzae), has become increasingly important in South America, where the disease is still spreading. We used 11 microsatellite loci to elucidate the population structure of the wheat blast pathogen in wheat fields in central-western, southeastern, and southern Brazil. No subdivision was found among the wheat-infecting populations, consistent with high levels of gene flow across a large spatial scale. Although the clonal fraction was relatively high and the two mating type idiomorphs (MAT1-1 and MAT1-2) were not at similar frequencies, the clone-corrected populations from Distrito Federal and Goiás, Minas Triangle, and São Paulo were in gametic equilibrium. Based on these findings, we propose that populations of the wheat blast pathogen exhibit a mixed reproductive system in which sexual reproduction is followed by the local dispersal of clones. Seedling virulence assays with local wheat cultivars differentiated 14 pathotypes in the current population. Detached head virulence assays differentiated eight virulence groups on the same wheat cultivars. There was no correlation between seedling and head reactions.
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LURWANU, Yahuza. "In vitro efficacy of some fungicides for the management of Rice Blast Pathogen Magnaporthe oryzae." Moroccan Journal of Agricultural Sciences 6, no. 1 (2025): 43–47. https://doi.org/10.5281/zenodo.15076625.
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Fungicides are used in agriculture for the management of plant diseases for effective food production. In this study, we conducted an in vitro experiment using three synthetic fungicides on mycelium growth of Magnaporthe oryzae. Among the tested fungicides, percent mycelial growth inhibition was higher in Contaf 100 % concentration (86.1%) followed by Contaf 50 % concentration (85.0 %). The least inhibition was observed in Raksha 50% concentration with 43.3% inhibition. We also evaluated the effect of seed dressing chemicals on the percentage germination of rice seeds. The results showed that all seeds treated had over 80 % germination at 7 days after sowing (DAS) compared to untreated (control) seeds which had only 65 % germination. Germination was higher (85 %) at 7 days after sowing, with seeds treated with Raksha, followed by Star-dress with 84 % while the least germination was observed with the seeds treated with Apama plus 81 %. Furthermore, the impact of seed dressing chemicals on the rice seedling vigor was also evaluated. Highest seedling vigor was observed on seeds treated with Star-dress with mean seedling length of (22.5 cm) which showed the highest vigor index of 1893, followed by Apama plus with mean seedling length of (22.1 cm) and a vigor index of 1792. Least seedling length of (18.9 cm) was observed with Raksha which was even lower than the control (20.4 cm). Our results suggested that fungicides can be effectively administered for the management of plant diseases to support seed germination and seedling vigor.
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Timsina, Shraddha, and Sukritee Bhattarai. "BLAST DISEASE A MAJOR THREAT TO FOOD SECURITY: A REVIEW OF PATHOGEN AND STRATEGIES TO CONTROL." Sustainability in Food and Agriculture 4, no. 2 (2023): 55–60. http://dx.doi.org/10.26480/sfna.02.2023.55.60.
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Rice blast is caused by the fungi Magnaporthe oryzae, which belongs to the group Ascomycota. The disease cycle of rice blast begins with the infection of the plant tissue by the spores of the pathogen. The spores can be carried by wind, water, and insects, and can infect the plant at any growth stage, from seedling to the heading stage. Once the spore lands on the plant tissue, they germinate and penetrate the tissue through a specialized structure called appressoria. Inside the plant tissue, the fungus grows and produces lesions that appear as small grayish-white spots on the leaves, collar, neck, and panicle of the plant. Under favorable conditions, the lesions can enlarge rapidly, causing complete crop failure. The epidemiology of rice blasts is influenced by various factors, such as temperature, humidity, rainfall, wind, and varietal susceptibility. The pathogen can survive in the soil and plant debris for several months, providing a potential source of infection for the next crop. Several management strategies have been developed to control rice blasts, including cultural, botanical, nutrient management, biotechnological, and chemical methods. Chemical methods such as fungicides can be used to control the disease, but their use should be judicious to avoid the development of fungicide resistance and environmental pollution.
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Sharma, Rajan, A. G. Girish, H. D. Upadhyaya, et al. "Identification of Blast Resistance in a Core Collection of Foxtail Millet Germplasm." Plant Disease 98, no. 4 (2014): 519–24. http://dx.doi.org/10.1094/pdis-06-13-0593-re.
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Blast, also known as leaf spot, caused by Pyricularia grisea (teleomorph: Magnaporthe grisea), is a serious disease affecting both forage and grain production in foxtail millet in India. For the identification of new and diverse sources of blast resistance, a foxtail millet core collection comprising 155 accessions was evaluated against the Patancheru isolate (Fx 57) of M. grisea. In a field screen during 2009 and 2010, 21 accessions were identified with neck and head blast resistance against Fx 57. In a greenhouse screen, 11 of the 155 accessions exhibited seedling leaf blast resistance to the same isolate. Further evaluation of the selected 28 accessions (found resistant to neck and head blast under field conditions during 2009 and 2010 or leaf blast in the greenhouse screen) against four M. grisea isolates (Fx 57, Fx 58, Fx 60, and Fx 62 from Patancheru, Nandyal, Vizianagaram, and Mandya, respectively) led to the identification of 16 accessions with leaf, sheath, neck, and head blast resistance to at least one isolate. Two accessions (ISe 1181 and ISe 1547) were free from head blast infection and showed resistance to leaf (score ≤3.0 on a 1-to-9 scale), neck, and sheath blast (score ≤2.0 on a 1-to-5 scale) against all four isolates. In addition, ISe 1067 and ISe 1575 also exhibited high levels of blast resistance. Blast-resistant accessions with superior agronomic and nutritional quality traits can be evaluated in multilocation yield trials before releasing them for cultivation to farmers.
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Honda, Yuichi. "Control of Seedling Blast of Rice with Ultraviolet-Absorbing Vinyl Film." Plant Disease 69, no. 7 (1985): 596. http://dx.doi.org/10.1094/pd-69-596.
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G, THANGAMANI NARAYANASWAMY. "AN ECONOMIC SPRAY SCHEDULE FOR THE CONTROL OF RICE BLAST." Madras Agricultural Journal 81, February (1994): 78–79. http://dx.doi.org/10.29321/maj.10.a01314.
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The rice varieties IR50 and TKM-9 were raised in the second season favourable for blast. Treatments were in the form of seed treatment, nursery treatment or both in seedling stage and followed by two fungicidal spray in the mainfield at tillering and late booting along with a need based application and a control for comparison. All the treatments were found to be better than the need based and untreated control in recording a lower incidence of blast and a higher yield in both the varieties. It is observed from the present experiment that for susceptible varieties, need based application is not sufficient as it is in par with untreated control in all respects. A minimum protection not only reduces blast, but also helps in increansing the yield, even in a susceptible variety
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Maulana, Frank, Wangqi Huang, Joshua D. Anderson, Tadele T. Kumssa, and Xue-Feng Ma. "Genome-Wide Association Mapping of Seedling Vigor and Regrowth Vigor in Winter Wheat." Crops 1, no. 3 (2021): 153–65. http://dx.doi.org/10.3390/crops1030015.
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Seedling vigor and regrowth ability are important traits for the forage production of winter wheat. The objectives of this study were to map quantitative trait loci (QTL) associated with seedling vigor and regrowth vigor traits using a genome-wide association mapping study (GWAS). Seedling vigor and regrowth vigor were evaluated with shoot length, the number of shoots per plant and shoot dry weight per plant 45 days after planting and 15 days after cutting. A large phenotypic variation was observed for all the traits studied. In total, 12 significant QTL for seedling vigor and 16 for regrowth vigor traits were detected on various chromosomes. Four QTL on chromosomes 2B, 4B, 5A and 7A for seedling vigor co-localized with QTL for regrowth vigor due to significant correlations between corresponding traits of the initial growth and regrowth. A BLAST search using DNA sequences of the significant loci revealed candidate genes playing roles in vegetative and reproductive development in different crop species. The QTL and single-nucleotide polymorphism (SNP) markers identified in this study will be further validated and used for marker-assisted selection of the traits during forage wheat breeding.
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Manandhar, H. K., H. J. Lyngs Jørgensen, S. B. Mathur, and V. Smedegaard-Petersen. "Suppression of Rice Blast by Preinoculation with Avirulent Pyricularia oryzae and the Nonrice Pathogen Bipolaris sorokiniana." Phytopathology® 88, no. 7 (1998): 735–39. http://dx.doi.org/10.1094/phyto.1998.88.7.735.
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Avirulent isolates of Pyricularia oryzae and isolates of Bipolaris sorokiniana, a nonrice pathogen, were used to suppress rice blast caused by P. oryzae. In greenhouse experiments, both fungi substantially reduced leaf blast when applied 24 h or more before the pathogen. B. sorokiniana, but not avirulent isolates of P. oryzae, systemically reduced disease in leaf 5 when applied to whole plants at the four-leaf stage. In field experiments, both fungi were able to reduce neck blast significantly. No increase in grain yield was obtained by using avirulent isolates of P. oryzae, whereas five sprays with B. sorokiniana from seedling to heading stages increased the grain yield in two of three experiments conducted at two locations in Nepal. The significant increase in yield was observed under high inoculum pressure of P. oryzae. Induced resistance is suggested to be involved in the suppression of disease.
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B, DIVYA, ROBIN S, BISWAS A, and JOHN JOEL A. "Genetics of association among yield and blast resistance traits in rice (Oryza sativa)." Indian Journal of Agricultural Sciences 85, no. 3 (2015): 354–60. http://dx.doi.org/10.56093/ijas.v85i3.47118.
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Blast disease caused by the fungus Pyricularia oryzae is one of the serious threats to world's most important staple food crop, rice (Oryza sativa L.). The improvement of blast resistance is one of the priority areas in breeding. Knowledge about association of yield traits with resistance parameters should be of paramount importance prior to development of a high yielding resistant variety. The present study was designed to understand the association of different traits in the segregating generations (F3 and BC2F1) developed from a high yielding rice variety ADT 43 and a blast resistant Near Isogenic Line (NIL), viz. CT13432-3R. The associations among traits related to yield and blast resistance were investigated. The correlation and path analysis have shown that characters like lesion type, potential disease incidence, lesion number and infested leaf area has significant positive correlation and high positive direct effect with leaf blast susceptibility. Therefore it was concluded that selecting genotypes with lower lesion number, high seedling vigour and short compact panicles with less exertion are preferable to reduce leaf blast disease incidence. Single plant yield was positively correlated with plant height, number of productive tillers, panicle length and filled grains per panicle. The highest genotypic association to grain yield was contributed by number of productive tillers. Selection of genotypes for these traits will ultimately result in increased yield.
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Qin, Peng, Xiaochun Hu, Nan Jiang, et al. "A Procedure for Inducing the Occurrence of Rice Seedling Blast in Paddy Field." Plant Pathology Journal 37, no. 2 (2021): 200–203. http://dx.doi.org/10.5423/ppj.nt.12.2020.0216.
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Maekawa, Kazumasa, Masataka Aino, and Yutaka Iwamoto. "Control of rice blast occurred in seedling period by application of some fungicides." Annual Report of The Kansai Plant Protection Society 42 (2000): 75–76. http://dx.doi.org/10.4165/kapps1958.42.0_75.
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NG, LEE CHUEN, ZAHARI NURA ADILA, ELHAM MOHD SHAHRUL HAFIZ, AHMAD AZIZ, and MOHD RAZI ISMAIL. "FOLIAR SPRAYED-SILICON TO INDUCE DEFENSE-RELATED ENZYMATIC ACTIVITY AGAINST Pyricularia oryzae INFECTION IN AEROBIC RICE." Malaysian Applied Biology 49, no. 4 (2020): 213–21. http://dx.doi.org/10.55230/mabjournal.v49i4.1622.
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Rice blast disease caused by Pyricularia oryzae is the most devastative disease. The alternative in rice blast disease management using foliar silicon (Si) application is gaining attention. The mechanism underlying defense-related enzyme induced through foliar Si application is still scarce. This research aimed to elucidate the bio-efficacy of foliar Si in inducing defense-related enzyme activity against P. oryzae in two aerobic rice cultivars: MR219-4 (blast-partially resistant) and MARDI Aerob 1 (resistant). Calcium silicate at 9 mg/L was foliar-sprayed and the disease severity index was evaluated and transformed to the area under disease progress curves (AUDPC). Foliar Si application significantly reduced rice blast disease severities in both cultivars tested. The AUDPC was reduced to 96.57 (MR219-4) and 21.90 (MARDI Aerob 1), from 148.57 (MR219-4) and
 53.73 (MARDI Aerob 1). Plant defense-related enzymes: peroxidase (PO), polyphenol oxidases (PPO), and phenylalanine ammonia-lyase (PAL) were increased and might be associated to increase resistance. Also, there was a significant interaction (p=0.003) between rice cultivar and treatment to Si content in rice leaf. Thus, foliar application of Si in rice seedling underlined the important role of Si as a modulator in influencing plant defense-related enzymes with interacting with other stress signaling pathways leading to induce resistance.
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Thulasinathan, Thiyagarajan, Bharathi Ayyenar, Rohit Kambale, et al. "Marker Assisted Introgression of Resistance Genes and Phenotypic Evaluation Enabled Identification of Durable and Broad-Spectrum Blast Resistance in Elite Rice Cultivar, CO 51." Genes 14, no. 3 (2023): 719. http://dx.doi.org/10.3390/genes14030719.
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Across the globe, rice cultivation is seriously affected by blast disease, caused by Magnaporthe oryzae. This disease has caused heavy yield loss to farmers over the past few years. In this background, the most affordable and eco-friendly strategy is to introgress blast-resistant genes from donors into elite rice cultivars. However, it is not only challenging to evolve such resistance lines using conventional breeding approaches, but also a time-consuming process. Therefore, the marker-assisted introduction of resistance genes has been proposed as a rapid strategy to develop durable and broad-spectrum resistance in rice cultivars. The current study highlights the successful introgression of a blast resistance gene, i.e., Pi9, into CO 51, an elite rice cultivar which already has another resistance gene named Pi54. The presence of two blast resistance genes in the advanced backcross breeding materials (BC2F2:3) was confirmed in this study through a foreground selection method using functional markers such as NBS4 and Pi54MAS. The selected positive introgressed lines were further genotyped for background selection with 55 SSR markers that are specific to CO 51. Consequently, both Pi9 as well as Pi54 pyramided lines, with 82.7% to 88.1% of the recurrent parent genome recovery, were identified and the selected lines were evaluated under hotspot. The analysis outcomes found that both the lines possessed a high level of resistance against blast disease during the seedling stage itself. In addition to this, it was also noticed that the advanced breeding rice lines that carry Pi9 + Pi54 were effective in nature and exhibited a higher degree of resistance against blast disease compared to the lines that were introgressed with a single blast resistance gene. Thus, the current study demonstrates a rapid and a successful introgression and pyramiding of two blast resistance genes, with the help of markers, into a susceptible yet high-yielding elite rice cultivar within a short period of time. Those gene pyramided rice lines can be employed as donors to introgress the blast-resistant genes in other popular susceptible cultivars.
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ROY, Krishna Kanta, Muzahid RAHMAN, Kishowar MUSTARIN, et al. "First report of blast of durum wheat in Bangladesh, caused by Magnaporthe oryzae pathotype Triticum." Phytopathologia Mediterranea 60, no. 1 (2021): 105–11. http://dx.doi.org/10.36253/phyto-11821.
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Durum wheat (Triticum turgidum var. durum Desf.) is an important cereal crop in many regions of the world. In March of 2018 and 2019, symptoms typical of blast were frequently observed on durum wheat plants under field conditions in Jashore, Bangladesh. The putative causal pathogen was isolated from infected wheat spike specimens onto potato dextrose agar and oatmeal agar, and was identified from mono-conidium cultures as Magnaporthe oryzae, based on morphological features. The pathotype of the fungus was identified as Triticum, based on comparative molecular analyses of ITS sequences and MoT3 specific markers. BLAST analysis revealed >99.8% similarity with M. oryzae/P. oryzae, retrieved from the NCBI Genebank. This was confirmed through amplification of the predicted products with MoT3 primers in PCR analysis. Pathogenicity was confirmed by inoculating healthy durum wheat seedling leaves and spikes with a conidium suspensions of M. oryzae isolate DuBWMRI1901.2A. The fungus produced similar symptoms on inoculated leaves and spikes as those observed in the field, and was subsequently re-isolated, fulfilling Koch’s postulates. This is the first report of blast of durum wheat caused by Magnaporthe oryzae pathotype Triticum in Bangladesh.
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Martinez, Sergio I., Alex Wegner, Stefan Bohnert, Ulrich Schaffrath, and Analía Perelló. "Tracing seed to seedling transmission of the wheat blast pathogen Magnaporthe oryzae pathotype Triticum." Plant Pathology 70, no. 7 (2021): 1562–71. http://dx.doi.org/10.1111/ppa.13400.
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Kang, Beum-Kwan, Ji-Young Min, Yun-Sik Kim, et al. "The Effect of Fungicides against Rice Blast by the Nursery Treatment at Rice Seedling." Research in Plant Disease 10, no. 1 (2004): 69–72. http://dx.doi.org/10.5423/rpd.2004.10.1.069.
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Yang, Yanmei, Yifan Zhang, Luyi Zhang, et al. "Isolation of Bacillus siamensis B-612, a Strain That Is Resistant to Rice Blast Disease and an Investigation of the Mechanisms Responsible for Suppressing Rice Blast Fungus." International Journal of Molecular Sciences 24, no. 10 (2023): 8513. http://dx.doi.org/10.3390/ijms24108513.
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Rice yield can be significantly impacted by rice blast disease. In this investigation, an endophytic strain of Bacillus siamensis that exhibited a potent inhibitory effect on the growth of rice blast was isolated from healthy cauliflower leaves. 16S rDNA gene sequence analysis showed that it belongs to the genus Bacillus siamensis. Using the rice OsActin gene as an internal control, we analyzed the expression levels of genes related to the defense response of rice. Analysis showed that the expression levels of genes related to the defense response in rice were significantly upregulated 48 h after treatment. In addition, peroxidase (POD) activity gradually increased after treatment with B-612 fermentation solution and peaked 48 h after inoculation. These findings clearly demonstrated that the 1-butanol crude extract of B-612 retarded and inhibited conidial germination as well as the development of appressorium. The results of field experiments showed that treatment with B-612 fermentation solution and B-612 bacterial solution significantly reduced the severity of the disease before the seedling stage of Lijiangxintuan (LTH) was infected with rice blast. Future studies will focus on exploring whether Bacillus siamensis B-612 produces new lipopeptides and will apply proteomic and transcriptomic approaches to investigate the signaling pathways involved in its antimicrobial effects.
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HARASAWA, R. "Predicting the onset of general epidemics of rice leaf blast based on development of leaf blast in seedling mats left in paddy fields." Japanese Journal of Phytopathology 67, no. 2 (2001): 87–96. http://dx.doi.org/10.3186/jjphytopath.67.87.
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Paul, Sanjoy Kumar, Moutoshi Chakraborty, Mahfuzur Rahman, et al. "Marine Natural Product Antimycin A Suppresses Wheat Blast Disease Caused by Magnaporthe oryzae Triticum." Journal of Fungi 8, no. 6 (2022): 618. http://dx.doi.org/10.3390/jof8060618.
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The application of chemical pesticides to protect agricultural crops from pests and diseases is discouraged due to their harmful effects on humans and the environment. Therefore, alternative approaches for crop protection through microbial or microbe-originated pesticides have been gaining momentum. Wheat blast is a destructive fungal disease caused by the Magnaporthe oryzae Triticum (MoT) pathotype, which poses a serious threat to global food security. Screening of secondary metabolites against MoT revealed that antimycin A isolated from a marine Streptomyces sp. had a significant inhibitory effect on mycelial growth in vitro. This study aimed to investigate the inhibitory effects of antimycin A on some critical life stages of MoT and evaluate the efficacy of wheat blast disease control using this natural product. A bioassay indicated that antimycin A suppressed mycelial growth (62.90%), conidiogenesis (100%), germination of conidia (42%), and the formation of appressoria in the germinated conidia (100%) of MoT at a 10 µg/mL concentration. Antimycin A suppressed MoT in a dose-dependent manner with a minimum inhibitory concentration of 0.005 μg/disk. If germinated, antimycin A induced abnormal germ tubes (4.8%) and suppressed the formation of appressoria. Interestingly, the application of antimycin A significantly suppressed wheat blast disease in both the seedling (100%) and heading stages (76.33%) of wheat at a 10 µg/mL concentration, supporting the results from in vitro study. This is the first report on the inhibition of mycelial growth, conidiogenesis, conidia germination, and detrimental morphological alterations in germinated conidia, and the suppression of wheat blast disease caused by a Triticum pathotype of M. Oryzae by antimycin A. Further study is required to unravel the precise mode of action of this promising natural compound for considering it as a biopesticide to combat wheat blast.
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Obasa, Ken, and Leonard Haynes. "Two New Bacterial Pathogens of Peanut, Causing Early Seedling Decline Disease, Identified in the Texas Panhandle." Plant Disease 106, no. 2 (2022): 648–53. http://dx.doi.org/10.1094/pdis-07-21-1555-re.
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Peanut (Arachis hypogaea L.) is cultivated in tropical and subtropical regions of the world as an important source of oil and protein. Until now, bacterial wilt, caused by Ralstonia solanacearum, was the only known bacterial disease of peanut. In 2020, widespread incidence of poor stand establishment was observed in multiple production fields planted to the Spanish-type peanut varieties in the Texas Panhandle. The observed symptoms included seed rot, pre- and postemergence damping-off, poor seedling vigor, poorly developed root systems with little or no nodule formation, and death. Subsequent diagnosis of symptomatic seedlings recovered two bacterial species identified by BLAST using 676- and 661-bp 16S rRNA fragments as a Ralstonia sp. and a Pantoea sp., respectively. To investigate a possible causative role of these bacteria in the observed peanut disease, the pathogenicity of the two isolates was evaluated under greenhouse conditions relying on Koch’s postulates. Cell suspensions of the two bacteria, separately and in combination, were used to inoculate seeds of a Valencia-type peanut variety with no history of the disease and found to be pathogenic on the resultant seedling plants. Symptoms that developed on the inoculated plants were similar to the symptoms initially observed in the field, including seed rot, pre- and postemergence damping-off, poor seedling vigor, and root establishment. The two bacteria were also successfully recovered from inoculated and symptomatic plants, thus satisfying Koch’s postulates. Given the early onset of symptom development on affected seeds and seedlings, a seedborne origin of the disease, described here as early-decline bacterial disease of peanut, was investigated in the same batches of peanut seeds that were planted, as well as seeds later harvested in some of the affected fields. Identical bacterial species, on the basis of 16S rRNA identity, were recovered from all of the seeds evaluated indicating that the bacteria are both seedborne and seed-transmissible. Multilocus sequence analysis involving six genes (dnaK, fumC, gyrB, murG, trpB, and tuf) showed that these new strains are most closely related to R. pickettii and Pantoea dispersa, but also phylogenetically distinct. The two bacteria were designated Ralstonia sp. strain B265 and Pantoea sp. strain B270. Losses from the disease in affected fields in 2020 averaged 50% (US$1.12 million) from a total of nine production fields. Findings from this study provide evidence for two new bacterial pathogens of peanuts capable of infecting Spanish and Valencia peanut varieties.
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Çağlayan, Kadriye, Çiğdem Ulubaş Serçe, Eminur Barutçu, et al. "Comparison by Sequence-Based and Electron Microscopic Analyses of Fig mosaic virus Isolates Obtained from Field and Experimentally Inoculated Fig Plants." Plant Disease 94, no. 12 (2010): 1448–52. http://dx.doi.org/10.1094/pdis-11-09-0771.
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Fig mosaic disease (FMD) and the fig mite, Aceria ficus, are widespread in different fig growing provinces of Turkey. Fig trees (Ficus carica) cv. Bursa siyahı (D1) and an unknown seedling (D2) that showed typical FMD symptoms and was heavily infested by fig mites were used as donor plants for attempted mite transmissions to healthy fig seedlings. Transmission electron microscopy observations of donor plant samples prior to the transmission tests were performed and showed the presence of double membrane bodies (DMBs) in the palisade mesophyll cells. Electron microscopy of all experimentally inoculated fig seedlings showed the same bodies. This result reinforced the suggestion that an agent that elicits the production of DMBs in infected cells is involved in the etiology of FMD. Double-stranded (ds)RNA analyses were also performed from experimentally inoculated plants, and dsRNAs with sizes approximately 1.30 and 1.96 kb were obtained. Reverse transcription–polymerase chain reaction (RT-PCR) products of 468 and 298 bp specific to Fig mosaic virus (FMV) were amplified from both donor and experimentally inoculated plants. BLAST analyses of nucleotide sequences of these fragments showed 90% identity with FMV for the donor plant and 94 to 96% for experimentally inoculated plants. According to these results, FMV is present in both donor and experimentally inoculated plants in Turkey, and this virus is transmissible by A. ficus from fig plant to fig plant.
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Chen, Huilan, Shiping Wang, and Qifa Zhang. "New Gene for Bacterial Blight Resistance in Rice Located on Chromosome 12 Identified from Minghui 63, an Elite Restorer Line." Phytopathology® 92, no. 7 (2002): 750–54. http://dx.doi.org/10.1094/phyto.2002.92.7.750.
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Bacterial blight, caused by Xanthomonas oryzae pv. oryzae, is a serious disease of rice worldwide. A new dominant gene for bacterial blight resistance in rice, Xa25(t), was identified from Minghui 63, a restorer line for a number of rice hybrids that are widely cultivated in China. This gene conferred resistance to Philippine race 9 (PXO339) of X. oryzae pv. oryzae in both seedling and adult stages. It was mapped to the centromeric region of chromosome 12, 2.5 cM from a disease resistance gene-homologous sequence, NBS109, and 7.3 cM from a restriction fragment length polymorphism marker, G1314. The genomic location of this gene is similar to the previously identified blast resistance genes, Pi-ta and Pi-ta2.
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R L, Neethukrishna, P. Arunasri, T. M. Hemalatha, M. K. Jyosthna, L. Madhavilatha, and M. Reddikumar. "Temporal Dynamics of Induced Enzymes in Finger Millet: The Impact of Neem Leaf Extract and Brevibacillus brevis in Blast Disease Management." Journal of Advances in Biology & Biotechnology 27, no. 7 (2024): 1388–400. http://dx.doi.org/10.9734/jabb/2024/v27i71102.
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Ragi or finger millet (Eleusine coracana (L.) Gaertner) is one of the common millets in several regions of India. The present study investigated enzymatic responses of finger millet leaves upon inoculation with the blast pathogen, Pyricularia grisea Sacc. and subsequent treatments with bio-agent, botanical, fungicide and salicylic acid. Enzymatic responses viz., β-1,3-glucanase, chitinase and lipoxygenase (LOX) were examined spectrophotometrically (at 24, 48 and 72 hours after treatment), which are pivotal components of the plant defense system. The pathogen was inoculated at twenty-one days old seedlings and immediately upon symptom development, the treatments were imposed. Treatments included seedling root dip and foliar spray with bacterial antagonist, Brevibacillus brevis; foliar spray with neem leaf extract (1500 ppm), carbendazim 12%+ mancozeb 63% (500 ppm) and salicylic acid (50 μM), challenged and unchallenged control. The results revealed that the enzymatic response of β-1,3-glucanase exhibited its highest activity at 24 hours post-treatment in foliar spray with neem leaf extract, whereas chitinase activity reached its maximum at 72 hours post-treatment with neem leaf extract, with a value of 0.75 µg glucose min-1 mg-1 protein. Lipoxygenase enzyme showed its peak activity at 48 hours post-treatment with neem leaf extract, showing a significant increase from 264.72 to 474.62 µmol/HPO/min compared to other treatments.
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TASHIMA, Shigeru, Akira KAWAGUCHI, Hiromu KASHINO, et al. "Long-Term Control of Rice Blast Disease by Seedling Box Application of Controlled Release Granules Containing Metominostrobin." Journal of Pesticide Science 24, no. 3 (1999): 287–89. http://dx.doi.org/10.1584/jpestics.24.287.
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HAYASAKA, T., H. FUJII, H. ANDO, and T. NAMAI. "Suppression of rice seedling blast by application of silica gel as a silicon source to nursery soil." Japanese Journal of Phytopathology 66, no. 1 (2000): 18–22. http://dx.doi.org/10.3186/jjphytopath.66.18.
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HAYASAKA, T., T. MATSUURA, and T. NAMAI. "Behavior and control of Pyricularia oryzae in brown rice seed as inoculum source of rice seedling blast." Japanese Journal of Phytopathology 68, no. 3 (2002): 297–304. http://dx.doi.org/10.3186/jjphytopath.68.297.
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Qi, Min, and Yinong Yang. "Quantification of Magnaporthe grisea During Infection of Rice Plants Using Real-Time Polymerase Chain Reaction and Northern Blot/Phosphoimaging Analyses." Phytopathology® 92, no. 8 (2002): 870–76. http://dx.doi.org/10.1094/phyto.2002.92.8.870.
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Rice blast, caused by Magnaporthe grisea, is a serious fungal disease of rice worldwide. Currently, evaluation of the fungal pathogenicity and host resistance is mainly based on a disease rating or measurement of blast lesion number and size. However, these methods only provide visual estimation rather than accurate measurement of fungal growth in rice plants. In this study, DNA-based real-time polymerase chain reaction (PCR) and RNA-based northern blot/phosphoimaging analyses were evaluated to quantify M. grisea. Both methods were sensitive, specific, and reproducible and could accurately measure the relative growth and absolute biomass of M. grisea. The real-time PCR analysis showed that the growth of M. grisea in seedling leaves of susceptible cultivars (M201 and Wells) was ≈46 to 80 times higher than that of a resistant cultivar (Drew) at 4 and 6 days after inoculation. The data obtained from the real-time PCR assays also were consistent with that from northern blot/ phosphoimaging analysis. However, the real-time PCR approach was much faster and more convenient in most cases. Therefore, it is an excellent tool for in planta quantification of M. grisea and can be used for reliable assessment of fungal pathogenicity and host resistance
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Hyder, Sajjad, Muhammad Inam-ul-Haq, Raees Ahmed, et al. "First Report of Phytophthora capsici Infection on Bell Peppers (Capsicum annuum L.) from Punjab, Pakistan." International Journal of Phytopathology 7, no. 1 (2018): 51. http://dx.doi.org/10.33687/phytopath.007.01.2543.
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Bell pepper (Capsicum annuum L.) is one of the extensively cultivated vegetable crop in Punjab, Pakistan. During two years of field surveys, February-November 2016-17, damping off and blight symptoms were observed. Average seedling mortality was recorded as 18.7% while yield loss due to blight was estimated 32 to 41% at mature stages. Maximum blight infection was recorded from the areas frequently flooded with canal irrigation system. At early stages, lesions were noticed on stem portions at soil line level while at crop maturity stages blight symptoms were noted. Leaves were blanched and wilted while fruits were covered with white mold. Masses of sporangia were evident on and inside the infected fruits under humid conditions. A total of twelve isolates were recovered from infected root, stem and fruit portions on rye agar media (Caten and Jinks, 1968) incubated at 25oC under fluorescent light. Papillated sporangia were averaged 42 ± 2.6 X 27 ± 1.7 μm in size (range 27 - 52 × 23 - 36 μm). Oospores were produced on 20% V8 agar and were spherical 22 ± 1.4 μm in diameter (range 14 to 27 μm) while average pedicels length was recorded as 58 ± 12.5 μm (range 13 to 120 μm). These observations were similar to those described for P. capsici (Cocoa, 1988). DNA was extracted using Cetyl Trimethylammonium Bromide (CTAB) method and the internal transcribed spacer regions (ITS1 and ITS2) were amplified by polymerase chain reaction (White et al., 1990). The amplicons were purified and sequenced in both directions (GenBank Accession No. MF322868 and MF322869). BLAST analysis revealed these isolates showed 99% identity with ITS sequences of Phytophthora capsici (KM369964 and KU518782). Pathogenicity assay was performed on healthy bell pepper seedlings with five repeats. Soil was flooded with 20ml sporangial suspension (1 x 103 sporangia/ml) in pots containing seedlings while 5ml suspension was sprayed until run off on mature plants (Hyder et al., 2018). A set of uninoculated seedlings was used as control. Pots were kept in dew chamber for 10-20 days at 25±2 oC. Seedling mortality was observed five days after inoculation while at later stage plants develop brown-to-black stem lesions with white mycelial growth on leaves. These symptoms were identical to the P. capsici infections in field. Consistent re-isolations of P. capsici confirm its association with the disease. To our knowledge, this is the first report of Phytophthora blight on bell pepper from Pakistan
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Santoso, Santoso, Anggiani Nasution, and Nani Yunani. "KERAGAMAN DAN SUMBER GEN KETAHANAN VARIETAS PADI LOKAL TERHADAP PATOGEN Pyricularia grisea PENYEBAB PENYAKIT BLAS." Jurnal Ilmu-Ilmu Pertanian Indonesia 22, no. 2 (2020): 119–28. http://dx.doi.org/10.31186/jipi.22.2.119-128.
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[DIVERSITY AND THE SOURCE OF RESISTANCE GENE OF LOCAL RICE VARIETIES ON THE PATHOGENIC OF Pyricularia grisea CAUSE OF BLAST DISEASE]. Local rice varieties are known to have resistance or source of genes to pests even though their productivity yield is low. The pathogen of Pyricularia grisea is a cause of blast disease, which is one of the obstacles in rice production. The research aims to characterize the resistance of local rice varieties to the pathogen of P. grisea and to evaluate the virulence level of P. grisea pathogens against local rice varieties. A total of 100 local rice varieties and check varieties are susceptible and resistant namely Kencana Bali and Situ Patenggang tested their resistance to 4 dominant pathogenic of P. grisea i.e. races 033, 073, 133 and 173. Inoculation was carried out on stages 4-5 leaves or 18-21 days after seedling in a green house. The results showed a high genetic diversity of local rice varieties against pathogenic races 033, 073, 133 and 173. Based on the response of local rice varieties resistance i.e. moderately resistant (MR), resistant (R) and susceptible (S) to pathogenic races 033, 073 , 133 and 173 obtained 45 resistance response patterns. Cere Bereum varieties which are local rice varieties from West Java and Situ Patenggang resistant check varieties have a resistant response to 4 P. grisea pathogenic races used. A number of local rice varieties also show a resistant and moderately resistant response to the four pathogenic races used include Siam 11, Pare Siriendah, Menyan, Cere Manggu and Enud-Rawa Bogo. Local rice varieties Djedah and Padi Hitam (2) are local rice varieties that have a specific response of resistant or moderately resistant to race 173. Race 133 and 173 have higher virulence rates than those of races 033 and 073 on local rice varieties. The results of this study indicate that there is a great potential for the utilization of local rice varieties, as a source of resistance genes for blast disease for the assembly of rice varieties that are resistant to blast disease.
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Uchihashi, Kaichi, Takamitsu Saito, Masahiro Minamoto, Takeshi Kanto, Kazumasa Maekawa, and Masataka Aino. "Effect of prevention against rice blast disease by resistance-inducing fungicide applied to seedling box in Hyogo Prefecture." Annual Report of The Kansai Plant Protection Society 59 (2017): 59–62. http://dx.doi.org/10.4165/kapps.59.59.
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Yoshii, Atsushi, Hiromitsu Moriyama, and Toshiyuki Fukuhara. "The Novel Kasugamycin 2′-N-Acetyltransferase Geneaac(2′)-IIa, Carried by the IncP Island, Confers Kasugamycin Resistance to Rice-Pathogenic Bacteria." Applied and Environmental Microbiology 78, no. 16 (2012): 5555–64. http://dx.doi.org/10.1128/aem.01155-12.
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ABSTRACTKasugamycin (KSM), a unique aminoglycoside antibiotic, has been used in agriculture for many years to control not only rice blast caused by the fungusMagnaporthe griseabut also rice bacterial grain and seedling rot or rice bacterial brown stripe caused byBurkholderia glumaeorAcidovorax avenaesubsp.avenae, respectively. Since both bacterial pathogens are seed-borne and cause serious injury to rice seedlings, the emergence of KSM-resistantB. glumaeandA. avenaeisolates highlights the urgent need to understand the mechanism of resistance to KSM. Here, we identified a novel gene,aac(2′)-IIa, encoding a KSM 2′-N-acetyltransferase from both KSM-resistant pathogens but not from KSM-sensitive bacteria. AAC(2′)-IIa inactivates KSM, although it reveals no cross-resistance to other aminoglycosides. Theaac(2′)-IIagene fromB. glumaestrain 5091 was identified within the IncP genomic island inserted into the bacterial chromosome, indicating the acquisition of this gene by horizontal gene transfer. Although excision activity of the IncP island and conjugational gene transfer was not detected under the conditions tested, circular intermediates containing theaac(2′)-IIagene were detected. These results indicate that theaac(2′)-IIagene had been integrated into the IncP island of a donor bacterial species. Molecular detection of theaac(2′)-IIagene could distinguish whether isolates are resistant or susceptible to KSM. This may contribute to the production of uninfected rice seeds and lead to the effective control of these pathogens by KSM.
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Li, Bai, Zhongkai Chen, Huizhen Chen, et al. "Stacking Multiple Genes Improves Resistance to Chilo suppressalis, Magnaporthe oryzae, and Nilaparvata lugens in Transgenic Rice." Genes 14, no. 5 (2023): 1070. http://dx.doi.org/10.3390/genes14051070.
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The ability of various pests and diseases to adapt to a single plant resistance gene over time leads to loss of resistance in transgenic rice. Therefore, introduction of different pest and disease resistance genes is critical for successful cultivation of transgenic rice strains with broad-spectrum resistance to multiple pathogens. Here, we produced resistance rice lines with multiple, stacked resistance genes by stacking breeding and comprehensively evaluated their resistance to Chilo suppressalis (striped rice stemborer), Magnaporthe oryzae (rice blast), and Nilaparvata lugens (brown planthopper) in a pesticide-free environment. CRY1C and CRY2A are exogenous genes from Bacillus thuringiensis. Pib, Pikm, and Bph29 are natural genes in rice. CH121TJH was introduced into CRY 1C, Pib, Pikm, and Bph29. CH891TJH and R205XTJH were introduced into CRY 2A, Pib, Pikm, and Bph29. Compared with those observed in their recurrent parents, CH121TJH significantly increased the mortality of borers. The other two lines CH891TJH and R205XTJH are the same result. Three lines introduction of Pib and Pikm significantly reduced the area of rice blast lesions, and introduction of Bph29 significantly reduced seedling mortality from N. lugens. Introduction of the exogenous genes had relatively few effects on agronomic and yield traits of the original parents. These findings suggest that stacking of rice resistance genes through molecular marker-assisted backcross breeding can confer broad spectrum and multiple resistance in differently genetic backgrounds.
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He, Wanwan, Nengyan Fang, Ruisen Wang, et al. "Fine Mapping of a New Race-Specific Blast Resistance Gene, Pi-hk2, in Japonica Heikezijing from Taihu Region of China." Phytopathology® 107, no. 1 (2017): 84–91. http://dx.doi.org/10.1094/phyto-03-16-0151-r.
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Heikezijing, a japonica rice landrace from the Taihu region of China, exhibited broad-spectrum resistance to more than 300 isolates of the blast pathogen (Magnaporthe oryzae). In our previous research, we fine mapped a broad-spectrum resistance gene, Pi-hk1, in chromosome 11. In this research, 2010-9(G1), one of the predominant races of blast in the Taihu Lake region of China, was inoculated into 162 recombinant inbred lines (RIL) and two parents, Heikezijing and Suyunuo, for mapping the resistance-blast quantitative trait loci (QTL). Three QTL (Lsqtl4-1, Lsqtl9-1, and Lsqtl11-1) associated with lesion scores were detected on chromosomes 4, 9, and 11 and two QTL (Lnqtl1-1 and Lnqtl9-1) associated with average lesion numbers were detected on chromosomes 1 and 9. The QTL Lsqtl9-1 conferring race-specific resistance to 2010-9(G1) at seedling stages showed logarithm of the odds scores of 9.10 and phenotypic variance of 46.19% and might be a major QTL, named Pi-hk2. The line RIL84 with Pi-hk2 derived from a cross between Heikezijing and Suyunuo was selected as Pi-hk2 gene donor for developing fine mapping populations. According to the resistance evaluation of recombinants of three generations (BC1F2, BC1F3, and BC1F4), Pi-hk2 was finally mapped to a 143-kb region between ILP-19 and RM24048, and 18 candidate genes were predicted, including genes that encode pleiotropic drug resistance protein 4 (n = 2), WRKY74 (n = 1), cytochrome b5-like heme/steroid-binding domain containing protein (n = 1), protein kinase (n = 1), and ankyrin repeat family protein (n = 1). These results provide essential information for cloning of Pi-hk2 and its potential utility in breeding resistant rice cultivars by marker-assisted selection.
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Abd Al-Qader, Zainab Adel, and Ali Hamood Thanoon. "Molecular Identification of Rhizoctonia solani Isolated from Cucumber (Cucumis sativus L.) and Its Biological Control." IOP Conference Series: Earth and Environmental Science 1371, no. 3 (2024): 032007. http://dx.doi.org/10.1088/1755-1315/1371/3/032007.
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Abstract At this study, the causative root rot agent was isolate and molecularly identified in cucumber which were grown in Nineveh province, northern of Iraq, in autumn season of 2022. A pathogenic fungus thought to be responsible for Cucumis sativus seedling damping-off disease and root rot. The symptoms of disease are the manifestation from partially yellowing on the leaves of cucumber, seedling damping-off to wilting of plant. Species of fungi isolated of infected plants were further grown on agar in form of potato dextrose which formed aerial mycelia as white to brown. The fungus was identified from the Morphological diagnosis as Rhizoctonia solani, and the pathogen was confirmed by Koch’s hypotheses as well as the results of amplification using the polymerase chain reaction (PCR) and nucleotide sequence analysis using BLAST showed that the R. solani isolate was genetically distinct from the R. solani isolates in the National Centre for Biotechnology Information (NCBI). Moreover, the complete verified ITS sequences are homologous to the isolates of R. solani in GenBank database having 99% similarity. Therefore, it was recorded in Gen Bank under the accession number OQ231503.1. and the results of the plastic tunnel showed that the Trichoderma harizanum T22 led to a significant reduction in the incidence and severity rate of infection recorded 64.17% and 23.500% respectively
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Matthiesen, R. L., A. A. Ahmad, M. L. Ellis, and A. E. Robertson. "First Report of Pythium schmitthenneri Causing Maize Seedling Blight in Iowa." Plant Disease 98, no. 7 (2014): 994. http://dx.doi.org/10.1094/pdis-08-13-0892-pdn.
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In spring 2012, maize farmers in southeast and south central Iowa reported stand losses due to pre- and post-emergence damping-off, and many of the fields had to be replanted. Symptoms of the disease included rotted seed, or brown, rotted, water-soaked mesocotyls and root tips. Maize seedlings with severe root and mesocotyl symptoms were yellow and wilted, stunted, or dead. The disease occurred approximately 2 weeks after cool, wet conditions. Symptomatic mesocotyls and roots were washed for 30 min, rinsed with sterile distilled water, and blotted dry on sterile paper towels. Isolation of the pathogen was performed by aseptically cutting 2- to 3-mm sections of tissue from the edge of a lesion, placing the segments under corn meal agar (CMA) containing pimaricin, ampicillin, rifampicin, and pentachloronitrobenzene (PARP), and incubating at 22°C in the dark. Colonies that developed were putatively identified as Pythium species based on morphological characteristics and cultural features when compared to published descriptions (2,3). Characteristics of isolate IAC12F21-3 included spherical and smooth-walled oogonia 18 to 26 μm in diameter, monoclinous or usually diclinous antheridia 10 to 22 μm long and 5 to 10 μm wide with one or occasionally two per oogonium, and plerotic oospores 15 to 25 μm in diameter. Sporangia were globose to ellipsoidal, 22 to 41 μm in diameter, and zoospores were 7 to 10 μm long. Primers ITS1 and ITS4 were used to amplify the ITS region within clade E1 of 88 isolates. The resultant amplicons were sequenced and a BLAST search in GenBank confirmed isolate IAC12F21-3 as Pythium schmitthenneri based on 100% similarity with GenBank accession numbers JF836869 and JF836870. Pathogenicity testing was conducted using seed and seedling assays (1,4). Koch's postulates was performed by sampling pieces of symptomatic mesocotyl and root tissue from the inoculated pots, placing segments under CMA + PARP, and incubating at 22°C. Symptoms were similar to those observed in the field and P. schmitthenneri was re-isolated successfully. Non-inoculated control plants showed no symptoms. This is the first report of P. schmitthenneri causing seedling blight on maize in Iowa. Previously, P. schmitthenneri was reported as a pathogen on maize in Ohio (2). References: (1) K. Broders et al. Plant Dis. 91:727, 2007. (2) M. Ellis et al. Mycologia, 104:477, 2012. (3) J. Middleton. Memoirs of the Torrey Botanical Club 20:171, 1943. (4) A. Rojas et al. Phytopathology, 102(Suppl):S5.8, 2012.
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Wortman, Sam E. "Integrating Weed and Vegetable Crop Management with Multifunctional Air-Propelled Abrasive Grits." Weed Technology 28, no. 1 (2014): 243–52. http://dx.doi.org/10.1614/wt-d-13-00105.1.
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Abrasive weed control is a novel weed management tactic that has great potential to increase the profitability and sustainability of organic vegetable cropping systems. The objective of this study was to determine the effect of air-propelled organic abrasive grits (e.g., organic fertilizers) on weed seedling emergence and growth and vegetable crop growth. A series of thirteen greenhouse trials were conducted to determine the susceptibility of weeds to abrasive weed control with one of six organic materials including: corn cob grits, corn gluten meal, greensand fertilizer, walnut shell grits, soybean meal, and bone meal fertilizer. In addition, crop injury was quantified to determine the potential utility of each organic material as abrasive grits in tomato and pepper cropping systems. Of the six organic materials, corn gluten meal, greensand fertilizer, walnut shell grits, and soybean meal provided the broadest range of POST weed control. For example, one blast of corn gluten meal and greensand fertilizer reduced Palmer amaranth (one-leaf stage) seedling biomass by 95 and 100% and green foxtail (one-leaf stage) biomass by 94 and 87%, respectively. None of the organic materials suppressed weed seedling emergence when applied to the soil surface, suggesting that residual weed control with abrasive grits is unlikely. Tomato and pepper stems were relatively tolerant of abrasive grit applications, though blasting with select materials did increase stem curvature in tomato and reduced biomass (corn cob grit) and relative growth rate (corn gluten meal and greensand) in pepper. Results suggest that organic fertilizers can be effectively used as abrasive grits in vegetable crops, simultaneously providing weed suppression and supplemental crop nutrition. Field studies are needed to identify cultural practices that will increase the profitability of multifunctional abrasive weed control in organic specialty crops.
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Shi, Xugen, Kang Qiao, Yong Zhang, et al. "Labor-saving application of thifluzamide and tricyclazole to seedling trays for integrated control of rice blast and sheath blight." Crop Protection 187 (January 2025): 107004. http://dx.doi.org/10.1016/j.cropro.2024.107004.
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