Bibliographic citations
Sánchez, E., (2018). Mustia hilachosa del frijol Thanatephorus cucumeris (Frank) Donk en la provincia de Coronel Portillo, departamento de Ucayali [Tesis, Universidad Nacional Agraria La Molina]. https://hdl.handle.net/20.500.12996/3641
Sánchez, E., Mustia hilachosa del frijol Thanatephorus cucumeris (Frank) Donk en la provincia de Coronel Portillo, departamento de Ucayali [Tesis]. : Universidad Nacional Agraria La Molina; 2018. https://hdl.handle.net/20.500.12996/3641
@mastersthesis{sunedu/3227592,
title = "Mustia hilachosa del frijol Thanatephorus cucumeris (Frank) Donk en la provincia de Coronel Portillo, departamento de Ucayali",
author = "Sánchez Marticorena, Eliel",
publisher = "Universidad Nacional Agraria La Molina",
year = "2018"
}
A survey for the presence of the perfect stage of Rhizoctonia solani was carried out in bean producing areas of the province of Coronel Portillo, Ucayali region. At the same time, it was looked for resistance to the fungus in bean cultivars introduced from CIAT-Colombia. Isolations were made in the laboratory of the National Agrarian University, La Molina and the greenhouse of the National University of Ucayali.The results of the survey showed that the fungus is distributed in all the surveyed areas; with a 9 and 38% average incidence. The four isolates of Thanatephorus cucumeris, obtained from the survey areas, showed differences in their cultural characteristics. The sclerotia produced in culture medium differed markedly from those formed on the bean plant; thus, in the culture medium the sclerotia reached a size of 1-5 mm, distributed individually on the plate or forming aggregates of 1 to 2 cm in diameter; whereas, those produced on the infected tissues had round or elliptical shapes whose size ranged between 0.5-1.0 mm in diameter.The 4 isolates obtained from Pucallpa, developed in a range of 25 to 30 ° C, but stopped growing above this level. Regarding pathogenicity, both in leaves and roots and hypocotyls, isolate 3 obtained from Pucalpillo were more pathogenic at the root and hypocotyl level; whereas, isolate 5 was the most pathogenic of the leaf level. All isolates were compared with anastomosis groups available in the UNA La Molina library (GA-1, GA.2 y GA-4). Isolates 3 and 5 were determined to correspond to the GA-4; whereas 1 and 4 corresponded to GA-1 Thirty-nine bean tolerant cultivars introduced from the International Center for Tropical Agriculture (CIAT) were evaluated in the greenhouse. Many showed little development and burns at the edges of the leaves; others, presented a high index of severity; while cultivar MUS-3 did not show symptoms of the disease. Cultivars MUS-18, DOR-364, BAT-1155 e BAT-1297, presented moderate symptoms of the disease on the tissue. When inoculating under greenhouse conditions with the most pathogenic isolate at leaf level, the five cultivars, introduced from CIAT, MUS-18, MUS-3, BAT-1297, BAT-1155 and DOR-364, had the lowest incidence rates, (2.85, 3.42, and 6.38% respectively). Regarding the severity, cultivars MUS-3 and BAT-1297 showed the lowest severity rates (0.19 and 0.16 % respectively). At the field level, the cultivars selected in the greenhouse confirmed their qualities: MUS-18 and MUS-3 with incidences of 2.85 and 3.42 and severity of 0.26 and 0.19 respectively, were considered resistant; while others, as tolerant; Also, the two cultivars with lower incidence and severity rates: MUS-3 and MUS-18, showed the highest yields of dry grain.
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