Abstract:RESUMOA utilização de métodos de inoculação constitui uma medida estratégica no estudo de resistência das cucurbitáceas. O objetivo deste trabalho foi avaliar dois métodos de inoculação de Rhizoctonia solani e Macrophomina phaseolina em meloeiro, visando o estudo de resistência. O experimento foi conduzido em casa de vegetação na Universidade Federal Rural do Semiárido, em Mossoró-RN, Brasil. Foram avaliados 05 acessos: A-09, A-16, A-18, A-22 e A-33 para R. solani e A-09, A-16, A-24, MR-1 e 'Olimpic' para M. p… Show more
“…The inoculation technique used was the toothpick method, because of the easy multiplication of inoculum and fast inoculation (Ambrósio et al, ; Medeiros et al, ; Mir et al, ). Twelve mm long toothpicks were placed, with the sharpened end up, in holes made in a 90‐mm‐diameter filter paper.…”
Section: Methodsmentioning
confidence: 99%
“…Based on this, a total of 94 isolates were tentatively identified as Macrophomina. All isolates were hyphal-tipped and, then, they were stored on sandy-organic substrate and Castellani's method with distilled water (Alfenas & Mafia, 2016;Medeiros, Melo, Ambrósio, Nunes, & Costa, 2015).…”
Section: Sampling and Fungal Isolationmentioning
confidence: 99%
“…The inoculation technique used was the toothpick method, because of the easy multiplication of inoculum and fast inoculation Medeiros et al, 2015;Mir et al, 2018). Thirty days after inoculation, the virulence of the isolates was assessed as disease severity using a modified version of the rating scale described by Ambrósio et al (2015), where 0 = symptomless, 1 = <3% of shoot tissues infected, 2 = 3%-10% of shoot tissues infected, 3 = 11%-25% of shoot tissues infected, 4 = 26%-50% of shoot tissues infected and 5 = more than 50% of shoot tissues infected.…”
Section: Pathogenicity and Virulence On Melonmentioning
In this work, a collection of 94 Macrophomina isolates obtained from roots of two weed species, Trianthema portulacastrum and Boerhavia diffusa, collected during surveys conducted during 2015 and 2016 in melon production fields in Northeastern Brazil, were characterized by using molecular techniques. Phylogenetic analysis of the EF1‐α gene allowed the identification of 32 isolates as M. phaseolina and 62 isolates as M. pseudophaseolina. Results of a pathogenicity test performed on melon seedlings of the cv. “Gladial” revealed that all M. phaseolina isolates inoculated were able to cause disease to melon seedlings, but only some M. pseudophaseolina isolates were able to infect them. This study represents the first report of M. pseudophaseolina in both T. portulacastrum and B. diffusa weeds, which are prevalent in the main Brazilian melon producing and exporting regions. Information about the biology and epidemiology of M. pseudophaseolina is scarce because of its recent description; thus, further research is needed for a better understanding of this fungus as a potentially emerging pathogen of melon and other crops.
“…The inoculation technique used was the toothpick method, because of the easy multiplication of inoculum and fast inoculation (Ambrósio et al, ; Medeiros et al, ; Mir et al, ). Twelve mm long toothpicks were placed, with the sharpened end up, in holes made in a 90‐mm‐diameter filter paper.…”
Section: Methodsmentioning
confidence: 99%
“…Based on this, a total of 94 isolates were tentatively identified as Macrophomina. All isolates were hyphal-tipped and, then, they were stored on sandy-organic substrate and Castellani's method with distilled water (Alfenas & Mafia, 2016;Medeiros, Melo, Ambrósio, Nunes, & Costa, 2015).…”
Section: Sampling and Fungal Isolationmentioning
confidence: 99%
“…The inoculation technique used was the toothpick method, because of the easy multiplication of inoculum and fast inoculation Medeiros et al, 2015;Mir et al, 2018). Thirty days after inoculation, the virulence of the isolates was assessed as disease severity using a modified version of the rating scale described by Ambrósio et al (2015), where 0 = symptomless, 1 = <3% of shoot tissues infected, 2 = 3%-10% of shoot tissues infected, 3 = 11%-25% of shoot tissues infected, 4 = 26%-50% of shoot tissues infected and 5 = more than 50% of shoot tissues infected.…”
Section: Pathogenicity and Virulence On Melonmentioning
In this work, a collection of 94 Macrophomina isolates obtained from roots of two weed species, Trianthema portulacastrum and Boerhavia diffusa, collected during surveys conducted during 2015 and 2016 in melon production fields in Northeastern Brazil, were characterized by using molecular techniques. Phylogenetic analysis of the EF1‐α gene allowed the identification of 32 isolates as M. phaseolina and 62 isolates as M. pseudophaseolina. Results of a pathogenicity test performed on melon seedlings of the cv. “Gladial” revealed that all M. phaseolina isolates inoculated were able to cause disease to melon seedlings, but only some M. pseudophaseolina isolates were able to infect them. This study represents the first report of M. pseudophaseolina in both T. portulacastrum and B. diffusa weeds, which are prevalent in the main Brazilian melon producing and exporting regions. Information about the biology and epidemiology of M. pseudophaseolina is scarce because of its recent description; thus, further research is needed for a better understanding of this fungus as a potentially emerging pathogen of melon and other crops.
“…Estudos com diferentes métodos de inoculação, em condições controladas, têm sido realizados com sucesso em diversas culturas (MEDEIROS et al, 2015;VENTUROSO et al, 2015;GARCIA et al, 2015).…”
Section: Introductionunclassified
“…Nesse sentido é fundamental a padronização de metodologias que possibilitem a seleção de forma segura de fontes de resistência à patógenos e a determinação precisa da reação, de resistência ou suscetibilidade dos genótipos avaliados (MEDEIROS et al, 2015).…”
Métodos de inoculação deResumo: A utilização de métodos de inoculação constitui uma ferramenta essencial no manejo de doenças, estudo de resistência, seleção e aplicação de produtos. O estudo teve como objetivo avaliar a eficiência de diferentes métodos de inoculação de Rhizoctonia bataticola em sementes de feijão. Os tratamentos constituíram de diferentes métodos de inoculação: suspensão de hifas, contato com restrição hídrica, inoculação do substrato com discos de BDA contendo micélio do fungo e um tratamento controle. Após a inoculação das sementes, foram feitas avaliações de emergência, comprimento de parte aérea, massa seca de parte aérea e incidência de doença na folha e no caule. O delineamento experimental foi inteiramente casualizado, com oito repetições, sendo os dados foram submetidos à análise de variância, sendo as médias comparadas pelo teste a Tukey 5% de probabilidade. O método de inoculação por suspensão de hifas é o mais adequado para inoculação de Rhizoctonia bataticola em sementes de feijão, visto que proporcionou uma maior incidência de plântulas infectadas sem afetar a emergência.
Palavras chave: Phaseolus vulgaris L., inoculação de sementes, podridão radicular.Abstract: The use of inoculation methods is an essential tool in the management of diseases, study of resistance, selection and application products. The study aimed to evaluate the efficiency of different Rhizoctonia inoculation methods bataticola in bean seeds. The treatments consisted of different methods of inoculation: hyphae suspension, contact with water restriction, inoculation of the substrate with BDA discs containing fungal mycelium and a control treatment. After inoculation of the seeds were made emergency assessments, shoot length, dry weight of shoot and incidence of disease in the leaf and stem. The experimental design was completely randomized with eight repetitions, the data and were subjected to analysis of variance and the averages were compared by Tukey test at 5% probability. The hyphal suspension for inoculation method is best suited for inoculation of Rhizoctonia bataticola bean seeds, as they provided a higher incidence of infected seedlings without affecting the emergency.
Macrophomina phaseolina is the causal agent of charcoal rot disease of melons and causes significant losses worldwide and causes significant losses worldwide The use of resistant cultivars is a desirable method for controlling this disease, but there is no information about the influence of temperature on the resistant behavior found in melon accessions. The purpose of the present study was to assess the effect of temperature on the reaction of six melon accessions selected previously for their resistant response to M. phaseolina. They were inoculated with the M. phaseolina isolate CMM-1531 and grown under accurately controlled environmental conditions at different temperature regimes (25, 28, 31, and 34 ºC) in a replicate experiment. The increase in temperature increased the severity of symptoms in most genotypes, but this effect was less pronounced in the highly susceptible control, the cultivar 'Piel de sapo', and in the most resistant accession, the wild African agrestis Ag-15591Ghana 2 that remained resistant even at 34ºC. The use of several screening temperatures allowed a better characterization of accessions that behaved similarly as highly resistant at 25ºC (Con-Pat81Ko, Dud-QMPAfg, Can-NYIsr and Ag-C38Nig), but in which resistance breaking was observed with temperature rise. Temperatures of 28ºC and 31ºC were sufficient to make Dud-QMPAfg, Ag-C38Nig and Can-NYIsr moderately resistant, whereas Con-Pat81Ko remained highly resistant. All these genotypes were susceptible at 34ºC, which suggest that are not suitable for hot-climate growing areas. The most promising accession was Ag-15591Ghana, whose resistance was confirmed in two greenhouse experiments under stressful temperatures (>34ºC). The behavior of these sources should be confirmed in naturally infested fields, but the controlled screening methods presented here are essential to characterize new resistance sources and to conduct genetic studies when a high number of plants must be managed under controlled environmental conditions.
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