Submitted to: Biological and Cultural Tests for Control of Plant Diseases
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/10/1999
Publication Date: N/A
Citation: Interpretive Summary: Early and late leaf spot are prevalent diseases in the U.S. peanut production areas. These diseases cost U.S. peanut farmers approximately $100 million in yield losses and cost of control. The objective of this study was to examine advanced peanut breeding lines for resistance to leaf spot. Twenty-four breeding lines, a highly susceptible cultivar, and a moderately resistant cultivar were grown in one location. Sixteen of th breeding lines had lower disease severity ratings than Florunner, the susceptible check cultivar, and Southern Runner, the moderately resistant check cultivar. Seventeen of the breeding lines had higher pod yields than Florunner. Five breeding lines had significantly higher yields and lower disease severity ratings compared to Southern Runner. This information will be used to determine which of these breeding lines have the potential to be released as cultivars.
Technical Abstract: Twenty-four peanut breeding lines were examined in 2-row 4.6 m long field plots for resistance to leaf spot. The research was conducted in a field of Tifton loamy sand at Coastal Plain Experiment Station, Tifton, GA. Peanuts were planted May 20,1998 (4 seed/30 cm) in two-row plots with row spacings of 0.9m. A randomized complete block design with three replications was used. Standard cultural practices for peanut production were followed with the exception that no fungicides were used for leaf spot control. Entire plots were rated for leaf spot severity 135 days after planting (DAP) and 144 DAP which was just before harvest. A subjective 1-10 rating scale based on disease incidence and defoliation where 1= no disease, and 10 = dead plant was used (Knauft et al., 1988, Peanut Sci. 15:9-13). All peanuts were dug 21 Oct. Samples were dried to 10% moisture before weighing. Data were subjected to analysis of variance, and Fisher's LSD Values (P<0.05) were calculated for mean separation. Cercosporidium personatum and Cercospora arachidicola were present in the test. Sixteen of the breeding lines had lower disease severity ratings than Florunner, the susceptible check cultivar, and Southern Runner, the moderately resistant check cultivar, both at 135 DAP and 144 DAP. Seventeen of the breeding lines had higher pod yields than Florunner. Five breeding lines C10-43, C11-20, C11-142, C11-154 and C12-54 had significantly higher yields and lower disease severity ratings compared to Southern Runner.