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

Abstract

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 mutatio n-derived lines (“Zar 9-9”, “RGS 8- 1”, “RGS 10-2”, “RGS 8-13” and “Talaye 8-3”) were d etermined under greenhouse condition. Methods of life table including the fema le age specific life table and the age- stage, two-sex life table were applied. According t o two-sex life table, there was no significant difference between demographic paramete rs of P. xylostella on “Talaye” and “Zar” in comparison with their mutant lines, but si gnificant 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 m utant lines and its control cultivar “RGS” in terms of population growth of the pest. Ac cording to the two-sex life table, the net reproductive rate ( R 0 ), intrinsic rate of increase ( r ), and finite rate of increase ( λ ) were the highest on RGS 8-1 (98.63 offspring per individ ual, 0.208 and 1.231 day -1 , respectively). Also, population projection showed t he 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. Investigati ng some consequences of plant breeding using radiation techniques on insect fitness not on ly leads plant breeders to do more unfailing selections but also provides some enlight enment in pest management programs effectively when plantation of such crops is priori tized. Keywords : Age-stage two-sex life table, Diamondback moth, F emale age-specific life table, Gamma ray, Insect fitness.