Boll weevil, Anthonomus grandis Boheman, oviposition nonpreference was measured on day-neutral lines of primitive cotton, Gossypium hirsutum L. The day-neutral lines were developed from photoperiodic stocks which were identified to be more resistant than M-8 in laboratory oviposition test in the early 1970's. The pbotoperiodic stocks were crossed to 'Deltapine 16' and the progeny were selected for the day-neutral flowering habit. These progeny were then backcrossed once or twice to their respective original primitive stocks and selected for day-neutrality after each backcross. Seven day-neutral lines (3F4's, 2BClF4's, and 2BC2F4's) were evaluated using a laboratory technique to measure boll weevil oviposition.

Six of the seven day-neutral lines (T-256DN F4, T-323DN F4, T-340DN F4, T-109DN BClF4, T-763DN BC2F4, and T-764DN BC2F4) received significantly less boll weevil oviposition than the susceptible checks, 'Stoneville 213' and Deltapine 611. The rate of oviposiiton on the day-neutral lines ranged from 69 to 81% of the check cultivars. The nature of the resistance is at present unknown; however, it is not attributed to any morphological trait.