By comparing their population parameters, fecundity and sex ratio, we examined the performance of four genetically variable populations of Trichogramma pretiosum Riley, two highly inbred pure lines (98%) with low and high performance (2 and 43 respectively) and two genetically variable lines (product of 26 inbred lines) with 2 or 40 generations. The population parameters determined were Ro, T, and λ as rm and fertility, and the overall results indicate significant differences between all the lines. The genetically variable line with two generations had the best performance, then the genetically variable with 40 generations, then line 43 and finally the pure line 2. Fertility and sex ratio were observed at 48 h and compared to overall. After 48 hours, no significant differences were found in fertility between the genetically variable lines to pure line 43. After 48 h, the sex ratio did not differ significantly between the two genetically variable lines and the pure line 43. However, total sexual ratios showed higher number of males in the genetically variable lines.
