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dc.contributor.advisorBanniza, Sabineen_US
dc.creatorMwakutuya, Edmoreen_US
dc.date.accessioned2006-04-20T17:47:55Zen_US
dc.date.accessioned2013-01-04T04:29:29Z
dc.date.available2006-04-21T08:00:00Zen_US
dc.date.available2013-01-04T04:29:29Z
dc.date.created2006-04en_US
dc.date.issued2006-04-07en_US
dc.date.submittedApril 2006en_US
dc.identifier.urihttp://hdl.handle.net/10388/etd-04202006-174755en_US
dc.description.abstractStemphylium blight is a defoliating fungal disease caused by Stemphylium botryosum. It has become more prevalent in Saskatchewan. Although not much is known about the biology of the fungus, increasing lentil (Lens culinaris) yield losses of up 62% have been reported in Bangladesh and India. The infection of lentil by S. botryosum was investigated under a range of temperatures (5 to 30°C), wetness periods (0 to 48 h) and wetness periods interrupted by dry periods of 6 to 24 h. The experiments involved testing the impact of environmental conditions on germination of conidia on glass slides and stemphylium blight infection on lentil (cv. CDC Milestone). Generalised linear models and non-parametric tests were used to determine the effects of these factors on conidial germination and disease development. Infection levels increased with increasing temperature and wetness duration. A latent period of 48 h was observed at 25°C and 30°C under continuous wetness. The duration of the latent period increased with decreasing temperatures and decreasing wetness duration. S. botryosum required warm temperatures (above 25°C) and a minimum wetness period of 8 h for optimal disease development. Low levels of infection were observed within the first 2 h of incubation at 10°C and increased with longer wetting periods up to 48 h and temperatures up to 30°C. The pathogen could maintain infectivity during interrupted wetness periods despite its requirement for prolonged wetness periods. Infection levels were not significantly affected by interrupting dry periods of 6 to 24 h although long dry periods (24 h) combined with higher temperatures (30°C) resulted in a decrease in stemphylium blight severity. Germination studies on glass slides supported these findings. Response surface models were developed that provided a good fit for the response of conidial germination to temperature and wetness duration. The coefficients of determination for the regression of observed against predicted effects ranged from 0.88 to 0.97. The general additive model could also be used to predict stemphylium blight severity responses to temperature and wetness duration (scaled deviance = 1.04). However, that model tended to overestimate infection levels especially at lower temperatures. The coefficients of determination for the observed against predicted effects at 5 to 30ºC ranged from 0.77 to 0.92 for the general additive model.en_US
dc.language.isoen_USen_US
dc.subjectlentilen_US
dc.subjectStemphylium blighten_US
dc.subjectSaskatchewanen_US
dc.titleEpidemiology of Stemhylium blight on lentil (Lens culinaris) in Saskatchewanen_US
thesis.degree.departmentPlant Sciencesen_US
thesis.degree.disciplinePlant Sciencesen_US
thesis.degree.grantorUniversity of Saskatchewanen_US
thesis.degree.levelMastersen_US
thesis.degree.nameMaster of Agriculture (M.Agr.)en_US
dc.type.materialtexten_US
dc.type.genreThesisen_US


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