Phenotyping Brachiaria Genotypes to Assess Rhizoctonia Resistance by Comparing Three Inoculum Types
| Autor: | John W. Miles, Elizabeth Alvarez, Margaret Worthington, Luis Miguel Hernández, Guillermo Sotelo, Ximena Bonilla |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
0106 biological sciences
0301 basic medicine food.ingredient Plant Science Rhizoctonia 01 natural sciences Rhizoctonia solani 03 medical and health sciences chemistry.chemical_compound food Blight Agar Mass screening biology business.industry fungi food and beverages Sowing biology.organism_classification Brachiaria Biotechnology Horticulture 030104 developmental biology chemistry Chlorophyll business Agronomy and Crop Science 010606 plant biology & botany |
| Zdroj: | Plant disease. 101(6) |
| ISSN: | 0191-2917 |
| Popis: | Rhizoctonia foliar blight, caused by Rhizoctonia solani, is an important disease of Brachiaria spp. in tropical America. Host-plant resistance is an attractive option for disease management. In this study, we evaluated three inoculum types (mycelium-infected agar disc, microdiscs suspensions, and microencapsulated-mycelium suspensions) in order to identify a rapid and accurate method for mass screening of Brachiaria genotypes for resistance to Rhizoctonia spp. in greenhouse trials. Visual damage score, area under the disease progress curve, and percent chlorophyll loss were estimated to determine the most accurate and precise method for evaluating Rhizoctonia resistance. The microencapsulated-mycelium solution (0.75 g/ml in potato dextrose broth sprayed on plants 30 days after planting) caused greater foliar damage than the other inoculum types and allowed effective discrimination between resistant and susceptible genotypes. The effectiveness of spray-applied, microencapsulated-mycelium was further corroborated by the evaluation of 350 genotypes not previously selected for resistance to Rhizoctonia spp., which varied significantly in their reaction to R. solani. The microencapsulated-mycelium methodology has several advantages over existing methods, including its high-throughput capacity, efficient use of time and space, ease of quantification of inoculum, and consistent results over replicate trials. This methodology could be applied to assess resistance to Rhizoctonia spp. in other crops. |
| Databáze: | OpenAIRE |
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