Evaluation of sorghum entries for resistance toHelicoverpa armigeraHübner (Lepidoptera: Noctuidae) under natural field conditions

Abstract

Abstract The relative resistance of 71 sorghum, Sorghum bicolor (L) Moench entries to the American bollworm, Helicoverpa armigera (Hüb.) (Lepidoptera: Noctuidae) was evaluated under natural field infestation condition in two locations in the eastern Sudan. The number of larvae per five heads (HL/5 heads) and the magnitude of damage (HOR), measured on a rating scale of 0–9, were used to measure resistance. The grand mean for the 71 entries was 7.80 and 1.95 in the first location, and 2.45 and 1.96 in the second location for HL/5 heads and HDR, respectively. The entries Tetron, Zanebelshah, P.988∗, Silca and Trokash were the least susceptible to H. armigera expressed as lowest larval counts and lowest damage ratings across both trials. The entries IS.7349∗, Feterita Iriana, Super Feterita, Culum, Wadelfahel, Fererita Bafta. Wad Yabis, White Aker and IS.7271∗ were the next most resistant as measured by the same parameters. None of these 14 entries, of which 11 were indigenous and three exotic, had mean HL/5 heads higher than 4.50 (<1 larva per head) or mean HDR of more than 1.0 in either trial.