Dynamics of late blight development and comparative resistance of potato varieties in Kenya

Host resistance is an important component for the management of late blight [Phytophthora infestans] on potato, in the highland tropics, where effective fungicide use is limited because of the cost of application. Potato cultivars with major resistance genes to late blight (population A) and minor o...

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Autores principales: Olanya, O., Ojiambo, P., Nyankanga, R.
Formato: Journal Article
Lenguaje:Inglés
Publicado: Informa UK Limited 2006
Materias:
Acceso en línea:https://hdl.handle.net/10568/99985
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author Olanya, O.
Ojiambo, P.
Nyankanga, R.
author_browse Nyankanga, R.
Ojiambo, P.
Olanya, O.
author_facet Olanya, O.
Ojiambo, P.
Nyankanga, R.
author_sort Olanya, O.
collection Repository of Agricultural Research Outputs (CGSpace)
description Host resistance is an important component for the management of late blight [Phytophthora infestans] on potato, in the highland tropics, where effective fungicide use is limited because of the cost of application. Potato cultivars with major resistance genes to late blight (population A) and minor or quantitative resistance genes to the disease (population B) were evaluated in field studies at two locations in Kenya during 2000, 2001, and 2002 cropping seasons. Disease severity, area under disease progress curve (AUDPC), infection rates, tuber blight, and tuber yields were assessed to determine the effectiveness of cultivar resistance to potato late blight. Significant differences (P < 0.05) in AUDPC were detected among cultivars. Progress of late blight on potato cultivars was best described by the nonlinear form of the logistic model. Infection rates ranged from 0.0047 to 0.3105 logits per day and were generally higher on susceptible than resistant cultivars. Rates of disease progress were highest on the susceptible control 'Kerr's Pink' (0.3015 logits per day) and lowest on ‘Rutuku' (0.0047 logits per day), a cultivar derived from population A. The rates of disease progress on population B cultivars were significantly (P < 0.001) higher than those on population A in seasons of severe late-blight epidemics. Significant (P < 0.05) differences in tuber blight development were also detected among the cultivars. Significant negative correlations were observed between AUDPC and tuber yield for cultivars of population A, but no correlations were observed for cultivars of population B. This suggests that cultivars of population B are less influenced in their yield by late blight than those of population A and may be more suited for use where late blight is a recurring problem.
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spelling CGSpace999852024-05-15T05:11:10Z Dynamics of late blight development and comparative resistance of potato varieties in Kenya Olanya, O. Ojiambo, P. Nyankanga, R. genes infection tropics blight Host resistance is an important component for the management of late blight [Phytophthora infestans] on potato, in the highland tropics, where effective fungicide use is limited because of the cost of application. Potato cultivars with major resistance genes to late blight (population A) and minor or quantitative resistance genes to the disease (population B) were evaluated in field studies at two locations in Kenya during 2000, 2001, and 2002 cropping seasons. Disease severity, area under disease progress curve (AUDPC), infection rates, tuber blight, and tuber yields were assessed to determine the effectiveness of cultivar resistance to potato late blight. Significant differences (P < 0.05) in AUDPC were detected among cultivars. Progress of late blight on potato cultivars was best described by the nonlinear form of the logistic model. Infection rates ranged from 0.0047 to 0.3105 logits per day and were generally higher on susceptible than resistant cultivars. Rates of disease progress were highest on the susceptible control 'Kerr's Pink' (0.3015 logits per day) and lowest on ‘Rutuku' (0.0047 logits per day), a cultivar derived from population A. The rates of disease progress on population B cultivars were significantly (P < 0.001) higher than those on population A in seasons of severe late-blight epidemics. Significant (P < 0.05) differences in tuber blight development were also detected among the cultivars. Significant negative correlations were observed between AUDPC and tuber yield for cultivars of population A, but no correlations were observed for cultivars of population B. This suggests that cultivars of population B are less influenced in their yield by late blight than those of population A and may be more suited for use where late blight is a recurring problem. 2006-03 2019-03-03T05:54:30Z 2019-03-03T05:54:30Z Journal Article https://hdl.handle.net/10568/99985 en Limited Access Informa UK Limited Olanya, O., Ojiambo, P. & Nyankanga, R. (2006). Dynamics of late blight development and comparative resistance of potato varieties in Kenya. Canadian Journal of Plant Pathology, 28, 84-89.
spellingShingle genes
infection
tropics
blight
Olanya, O.
Ojiambo, P.
Nyankanga, R.
Dynamics of late blight development and comparative resistance of potato varieties in Kenya
title Dynamics of late blight development and comparative resistance of potato varieties in Kenya
title_full Dynamics of late blight development and comparative resistance of potato varieties in Kenya
title_fullStr Dynamics of late blight development and comparative resistance of potato varieties in Kenya
title_full_unstemmed Dynamics of late blight development and comparative resistance of potato varieties in Kenya
title_short Dynamics of late blight development and comparative resistance of potato varieties in Kenya
title_sort dynamics of late blight development and comparative resistance of potato varieties in kenya
topic genes
infection
tropics
blight
url https://hdl.handle.net/10568/99985
work_keys_str_mv AT olanyao dynamicsoflateblightdevelopmentandcomparativeresistanceofpotatovarietiesinkenya
AT ojiambop dynamicsoflateblightdevelopmentandcomparativeresistanceofpotatovarietiesinkenya
AT nyankangar dynamicsoflateblightdevelopmentandcomparativeresistanceofpotatovarietiesinkenya