EVALUATION OF A SORGHUM POPULATION FOR RESISTANCE TO FALL ARMYWORM (LEPIDOPTERA, NOCUITDAE)

Several sorghum [Sorghum bicolor (L.) Moench] cultivars have been show n to possess moderate levels of resistance to fall armyworm (FAW), Spo doptera frugiperda (J.E. Smith). The objective of this study was to in crease this level of resistance by combining two elite sources of anti biosis. The inbred line 'AF28', which increases FAW larval mortality, was crossed with landrace San Bernardo III, which reduces FAW fecundit y. Fifty-nine F-4 inbred lines derived from this cross were screened i n 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 da ys 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 x 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 c ombined sources of resistance to FAW. Further tests with (AF28 x San B ernardo III)-28 in comparisons to sorghum, with and without antibiosis resistance, confirmed that (AF28 x San Bernardo III)-28 possesses the combined effects of both sources of antibiosis resistance. The effect s of the test sorghums on biological parameters of the FAW is evidence of heritable differences in resistance to this pest.