Influence of Genetic Selection on Diapause Termination of the Pink Boll worm1, 2, 3

Abstract

Investigations were conducted to determine if diapausetermination of the pink bollworm, Pectinophora gossypiella (Saunders), involves inherited characteristics. A 2-way selection was performed on a natural-diapausing population; the 1st larvae to terminate diapause composed an “early-pupating line” while the last larvae to terminate comprised a “late-pupating line.” Six and 5 generations were observed from the early- and late-pupating lines, respectively. The early-pupating line remained unchanged until the 5th generation and all generations terminated significantly earlier than those of the late line which was progressively later in terminating diapause with the longest termination time occurring in the 5th generation. Reciprocal crosses between the 2 lines indicated no dominance of either termination time. Sex-linkage was indicated, however, because the early-female × late-male cross-terminated significantly later than its reciprocal. Diapause termination appeared to be under genetic control in that the time of parental diapause termination influenced the time of diapause termination in the progeny. Consistency in the time of diapause termination in the early-pupating line indicated homogeneity of this characteristic. Conversely, the observed diversity in the time of diapause termination in the late individuals indicated a heterogeneous population.