Effect of Canola Physical Mutation on Plutella xylostella (L.) Life Table

Life history of insect herbivores is unclear after feeding on mutant lines of many crops. To shed light, demographic parameters of Plutella xylostella on three canola cultivars (“Zar”, “RGS”, “Talaye”) and their physical mutation-derived lines (“Zar 9-9”, “RGS 8-1”, “RGS 10-2”, “RGS 8-13” and “Talaye 8-3”) were determined under greenhouse condition. Methods of life table including the female age specific life table and the age-stage, two-sex life table were applied. According to two-sex life table, there was no significant difference between demographic parameters of P. xylostella on “Talaye” and “Zar” in comparison with their mutant lines, but significant differences were observed between these parameters on mutant lines of “RGS”. Having suitable cultural traits, “RGS 8-1” was more susceptible than the other two mutant lines and its control cultivar “RGS” in terms of population growth of the pest. According to the two-sex life table, the net reproductive rate (R0), intrinsic rate of increase (r), and finite rate of increase (λ) were the highest on RGS 8-1 (98.63 offspring per individual, 0.208 and 1.231 day-1, respectively). Also, population projection showed the rapid growth of the pest on the latter line. There was a little difference between the same population parameters estimated by two methods of life table. Investigating some consequences of plant breeding using radiation techniques on insect fitness not only leads plant breeders to do more unfailing selections but also provides some enlightenment in pest management programs effectively when plantation of such crops is prioritized.