Photosynthetic Consequences of Late Leaf Spot Differ between Two Peanut Cultivars with Variable Levels of Resistance

Singh, M.P. and Erickson, J.E. and Boote, K.J. and et al, . (2011) Photosynthetic Consequences of Late Leaf Spot Differ between Two Peanut Cultivars with Variable Levels of Resistance. Crop Science, 51 (6). pp. 2741-2748.

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Late leaf spot (LLS) caused by Cercosporidium personatum (Berk. & Curt.) Deighton reduces leaf CO2 assimilation rate (Asat) and accelerates leaf defoliation, which together lead to major reductions in peanut (Arachis hypogaea L.) yield worldwide. This study was conducted to determine whether differences in photosynthetic response to LLS severity exist among peanut cultivars of differing resistance. Field experiments were conducted in 2008 and 2009 to study the effects of LLS on Asat of tagged leaf cohorts, and photosynthetic response of similar age leaves to LLS in peanut cultivars with more (York) and less (Carver) quantitative resistance. A nonlinear model, y = (1 − x)β was used to analyze Asat data, where y is relative Asat, x is measured visual lesion area, and β represents the relationship between virtual and visual lesion area. Progression of LLS severity on leaf cohorts was slower in York than in Carver. However, the reduction in Asat with leaf cohort age was similar across the cultivars. This paradox could be explained by a higher β value in York (4.6) than in Carver (3.6), indicating a greater relative reduction in Asat beyond the necrotic lesion area in York. This greater reduction in Asat in York compared to Carver was most closely related to a reduction in maximum carboxylation velocity. Results indicated that future efforts to improve LLS resistance should include sustaining Asat in response to LLS infection along with slower disease progress.

Item Type: Article
Additional Information: This project was supported by the National Peanut Board Southeastern Peanut Research Initiative, Florida Peanut Producers Association, and the Florida Agricultural Experiment Station.
Uncontrolled Keywords: Assimilation rate, pathogens, Photosynthesis, Disease Severity, Data Analysis.
Author Affiliation: Agronomy Dep., Univ. of Florida, P.O. Box 110965, Gainesville, FL 32611
Subjects: Crop Improvement > Genetics/Genomics
Plant Physiology and Biochemistry > Plant Physiology
Divisions: Groundnut
Depositing User: Mr Balakrishna Garadasu
Date Deposited: 15 Mar 2013 10:52
Last Modified: 15 Mar 2013 10:52
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