Genetic variability of geographical populations of the bollworm, Helicoverpa armigera Hübner (Lepidoptera: Noctuidae), in west and northwest of IranAbstract : Old World or African bollworm, Helicoverpa armigera Hübner (Lep.: Noctuidae) is one of the key pests causing severe yield losses, infesting several crops such as cereals, pulses, cotton, vegetables and fruit crops as well as wild hosts. It is expected that the recognition of intraspecific variation, its nature and scope, may aid our understanding of the pest and also to predict its spatial and temporal occurrence, to devise effective management strategies, and also to characterize pod borer population responses to control measures. The purpose of this study is to estimate the relative importance of generic and environmental effects on characters of pod borer in Iran. Specimens were collected from several provinces in Iran from tomato. The genomic DNA from H. armigera larvae collected during summer 2006-2007 from five different places were subjected to polymerase chain reaction (PCR) using 10 different SSR primers. The highest numbers of 14 markers were produced by the primer HaSSR1, followed by 9 markers by HaSSR6 with high degree of polymorphism 75?100%. The primers HaSSR6, HaSSR4, HaC87 and HaD47 were found to be highly informative to differentiate populations with a polymorphism information content value of 100 percent. Ten tested SSR primers produced 46 bands in geographical populations. Within population genetic diversity based on Nie s gene index ranged from 0.188 to 0.250 Molecular variance analysis showed significant within and between population variance. The between and within geographical variance accounted for 13.88 and 86.12 percent of total molecular variance, respectively. Cluster analysis based on molecular data in geographical assigned the studied pod borer moth populations into two groups. In this grouping, group one consisted of Golestan population. The maximum and minimum genetic distances were observed between Gorgan- Mughan (0.21853) and Kermanshah- Shahindej (0.05789). Significant correction was not found between genetic and geographic matrices revealed by Mantel test.