Abstract: The populations of cotton bollworm, Helicoverpa arrnigera (Hubner), collected from Hami (HM), Xinjiang Uygur Autonomous Region and Hengyang (HY),Hunan Province in China, were crossed and backcrossed in the laboratory. The results showed that there was no significant difference in reproduction, hatching rate of eggsand reproductive duration between the F_l and F₂ moths of the two populations. The critical photoperiods for pupal diapause of HM, HY, HM♀× HY♂, HY♀×HM♂and (HY♀×HM♂)♀×HY♂ strains at 22℃ were 13 h 35 min, 11 h, 11 h 45 min, 11 h43 min and 11 h 9 min, respectively. The LT₅₀ values of diapause pupae of HM, HY,HM♀×HY♂ , HY♀×HM♂ ,HY♀×(HY♀×HM♂) ♂and (HY♀×HM♂)♀×HM ♂ at -15℃ were 159.74 h, 34. 2696 h, 100.65 h, 116. 75 h, 90.78 h and 135.58h, respectively, and the dominance degrees ID (HM♀×HY♂) and D (HY♀×HM♂)] were estimated to be 0.3998 and 0.5926. It indicated that the inheritance of cold hardiness in cotton hollworm is irrelevant to sex and controlled by multiple factors.

Key words: Helicoverpa arrnigera, reproduction, diapause, coldhardiness, inheri- tance