The nature of genetic variation in an intervarietal cross (J 34 × SS 167) of upland cotton was determined for seed cotton yield, number of bolls, weight of 100 seeds, ginning outturn and halo length. The materials consisted of six generations (P1, P2, F1, B1, B2 and F2) which were raised at two locations. In those cases where the additivedominance model was inadequate, models with different numbers of parameters were applied along with the six-parameter model. A consistent and high negative correlation was observed between [h] and [l], and [i] and [l] in all the models at two locations. Correlation between [d] and [i] was also consistent and negative, but its magnitude was low. Dominance and dominance × dominance, and additive × additive and dominance × dominance components were found to be antagonistic in effects to each other and the interactions observed were of duplicate type, i.e. [h] and [l] had opposite signs.

The dominance component fluctuated greatly over models for a particular character at a particular location. Contrary to this the additive component was observed to be important and consistent over models at a particular location for a particular character. Also this was the only significant component involved in the inheritance of all the characters at both the locations. The expression of different components of variation was highly influenced by the environmental effects.