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: Tomato spotted wilt virus (TSWV) is a relatively new disease in the U.S. peanut production areas. This virus can cause serious yield losses and there are no effective chemical control measures. The objective of this study was to examine advanced peanut breeding lines from two breeding programs for their reaction to TSWV. Fourteen breeding lines, a highly susceptible cultivar, and a moderately resistant cultivar were grown in tw locations. Ten of the breeding lines showed a significantly higher level of resistance to TSWV than the moderately resistant cultivar. Eight of these breeding lines also had significantly higher yield than the moderately resistant cultivar at both locations. This information will be used to determine which of these breeding lines have the potential to be released as cultivars.
Technical Abstract: Experiments were conducted at the Univ. of Georgia, Coastal Plain Expt. Station, Lang Farm, Tifton, GA and at the North Florida Research and Education Center, Marianna, FL. Randomized complete block designs with six replications were used in both locations. Genotypes evaluated included lines from the Univ. of Florida breeding program and the USDA breeding program and runner-type cultivars, Georgia Green and Georgia Runner as resistant and susceptible standards. All tests were maintained as recommended for commercial production. Plants were dug and inverted at approximate optimum maturity for each breeding line or cultivar based on the hull-scrape maturity index and/or visual maturity estimates. Pods were harvested mechanically, and pod yields were determined for each plot. Spotted wilt intensity ratings were made by counting the number of 0.31-m portions of row containing plants severely stunted, chlorotic, wilted, or dead due to spotted wilt. Five evaluations were made, with final intensit (FI) ratings made immediately prior to digging. Counts of severely affected loci were converted to percentage of row length severely affected. Area under the disease progress curve (AUDPC) was calculated for each plot, and AUDPC and FI ratings were used for comparison of genotypes. Epidemics of spotted wilt were severe at both locations. There was no significant location x genotype interaction for AUDPC or FI ratings. Across locations, AUDPC values of eight genotypes and FI ratings of ten genotypes were lower than those of Georgia Green. Location x genotype effects on yield were significant. Yields of eight lines were greater than those of Georgia Green in both locations.