Disease Progress of Early Leaf Spot and Components of Resistance to Cercospora arachidicola and Cercosporidium personatum in Runner-Type Peanut Cultivars

Cantonwine, E.G. and Culbreath, A.K. and Holbrook, C.C. and Gorbet, D.W. (2008) Disease Progress of Early Leaf Spot and Components of Resistance to Cercospora arachidicola and Cercosporidium personatum in Runner-Type Peanut Cultivars. Peanut science, 35 (1). pp. 1-10.

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Abstract

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

Item Type: Article
Uncontrolled Keywords: C11-2-39, partial resistance, field resistance, modeling
Author Affiliation: Department of Biology, Valdosta State University, Valdosta GA 31698
Subjects: Plant Protection > Pests
Divisions: Groundnut
Depositing User: Ms K Syamalamba
Date Deposited: 15 Nov 2011 05:05
Last Modified: 15 Nov 2011 05:05
Official URL: http://dx.doi.org/10.3146/0095-3679(2008)35[1:DPOE...
URI: http://eprints.icrisat.ac.in/id/eprint/2763

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