Gamma Irradiation of 4th Instar Larva of Angoumois Grain Moth and Effects on Parent and Their Generations

Abstract

Late fourth stage larvae of Angomous grain moth, Sitotroga cerealella (Olivier) were gamma irradiated with doses 0 ( control), 25, 50 75, 100, 125 and 150 Gy. The moths originated from larvae irradiated with 150 Gy became sterile. Irradiation of males as larvae with substerilizing doses of 25 and 50 Gy induced inherited F| sterility which reduced the population. F| progeny exhibited more sterility than their parent generation. Also F| males inherited more sterility than F| females. Adult fertility recovered in F2 and F3 generations. Increasing the competition ratio in favour of irradiated male parents or F| males and females from 1:1 to 5:1 (I:U) gave more reduction in egg viability. The percentage of egg infertility was increased by increasing the dose. The calculated competitiveness values for all ratios and doses used around 1.0 which mean that irradiated males 4- stage larvae or their F| moths were full competitive with normal moths and more effective in suppressing population of Angomous grain moth.