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Disease Progress of Early Leaf Spot and Components of Resistance to Cercospora arachidicola and Cercosporidium personatum in Runner-Type Peanut Cultivars
- This study assessed components of resistance for three runner-type peanut cultivars to infection by Cercospora arachidicola (Ca) and Cercosporidium personatum (Cp), the causal organisms of early leaf spot and late leaf spot, respectively. Resistance components were compared to disease resistance observed in the field. A field study monitored the progression of leaf spot incidence and severity in peanut cultivars Georgia Green, Georganic, and DP-1. Time of disease onset (TDO) and temporal epidemic rate (rate) were estimated for incidence with the logistic model, and for severity with the linear model. Early leaf spot was the predominant disease in the field. Estimates of TDO were 9 d later for DP-1 than for Georgia Green, based on incidence models, and 6 and 7 d later for Georganic and DP-1 than for Georgia Green, respectively, based on severity models. Incidence progression rate was highest for Georganic in 2002 and Georgia Green in 2003, while severity progression rate was highest for Georgia Green across years. A detached leaf assay was used to determine components of resistance for these genotypes to infections by Ca and Cp. Infection frequency 30 d after inoculation, lesion diameter, and percent necrotic area were greatest for Georgia Green for both pathogens. Besides a 2-d longer latent period for resistant genotypes, no Ca reproduction differences were detected. For Cp, latent period was shorter for Georganic than DP-1, and sporulation per unit lesion area was greatest for Georganic. Enhanced field resistance to early and late leaf spots reported for DP-1 and Georganic is in part due to lower infection frequencies, smaller lesions, and for DP-1, longer latent periods.
Cantonwine, E.G. , Culbreath, A.K. , Holbrook, C.C. , Gorbet, D.W.
Arachis hypogaea , peanuts , Cercospora , Cercosporidium , plant pathogenic fungi , fungal diseases of plants , disease course , disease resistance , cultivars , genetic resistance , field experimentation , disease outbreaks , disease severity , disease incidence , latent period
- Includes references
- Peanut science 2008 Jan-June, v. 35, issue 1
Journal Articles, USDA Authors, Peer-Reviewed
- Works produced by employees of the U.S. Government as part of their official duties are not copyrighted within the U.S. The content of this document is not copyrighted.