Abstract
Several sorghum [Sorghum bicolor (L.) Moench) cultivars have been shown to possess moderate levels of resistance to fall armywonn (FAW), Spodoptera frugiperda (J.E. Smith). The objective of this study was to increase this level of resistance by combining two elite sources of antibiosis. The inbred line 'AF28', which increases FAW larval mortality, was crossed with landrace San Bernardo III, which reduces FAW fecundity. Fifty-nine F4 inbred lines derived from this cross were screened in the field by artificial inoculation with FAW larvae. A scale of 0-9 was used to rate individual inbred lines for foliar damage 7 and 14 days after inoculation. The average of both rating dates ranged from 2.5 to 8.5 with a mean of 5.49. One inbred line, (AF28 × San Bernardo III)-28, was found to have a rating score more than 2 standard deviations below the mean and was determined to be a line possessing potential combined sources of resistance to FAW. Further tests with (AF28 × San Bernardo III)-28 in comparisons to sorghum, with and without antibiosis resistance, confirmed that (AF28 × San Bernardo III)-28 possesses the combined effects of both sources of antibiosis resistance. The effects of the test sorghums on biological parameters of the FAW is evidence of heritable differences in resistance to this pest.
