Gamma Radiation for sterile insect quality in melon fly, Zeugodacus cucurbitae (Coquillet)

The male pupae of Zeugodacus cucurbitae were exposed to eight different doses of gamma (Cobalt 60 source) radiation (10, 20, 30, 40, 50, 70, 90 and 100 Gy) to determine the optimum dose of gamma radiation that induces sterility with least negative effects on the quality of sterile males. Among eight doses, 50 Gy had induced 80.26% of sterility with the least negative effects on adult emergence (80.50%), adult flying ability (76.10%), deformation (7.90%), adult longevity (26 days) and survival under food stress (51.80%). Although more than 90% of sterility was obtained at 70, 90 and 100 Gy, quality parameters of sterile males, viz., flying ability, longevity, and survival were drastically affected with increased rates of deformations. Mating competitiveness of sterile males (SM) with normal males (NM) for their normal females (NF) at seven different sex ratios viz., 1:1:1, 2:1:1, 3:1:1, 4:1:1, 5:1:1, 7:1:1 and 9:1:1 showed the equally competitiveness of sterile males with normal males for their female mates at 5:1:1 with competitiveness value (CV) of 1.02. However, the sterile males showed superior competitiveness with normal males for their female mates at 7:1:1 (CV = 1.60) and 9:1:1 (CV = 1.98).