The Columbia lance nematode (CLN), Hoplolaimus columbus Sher.,is a serious pathogen of cotton in the Southeastern region of the United States. The use of tolerant cotton varieties is the most economical and environmentally safe method of CLN control. However, information comparing resistance or tolerance of cotton cultivars is limited. The objectives of this study were to identify the type of gene effects involved in the inheritance of any apparent field tolerance to CLN. Field studies were conducted at two locations under naturally infested nematode soil conditions using four suspected tolerant cotton (Gossypium hirsutum L.) cultivars (Deltapine 90, KC380, Stoneville 506, Coker 304) and one susceptible cotton cultivar (La. 213-613 RP) their crosses, and their respective generations P(1), P(2), F₁, F₂, F₃, BC(1)P(1), and BC(1)P(2).

Epistatic effects were significant in two of the four families evaluated. Additive and dominance effects were significant in one family. Gene action was different for each family and should prove useful in combining various parents for increased field tolerance to CLN.