The obvious symptoms of waterlogging response in cotton are leaf chlorosis (yellowing) and dropping squares & bolls. In addition, Huck (1970) showed that tap root growth stopped within 30 min of reducing the oxygen in the soils, and that the growing point of the root was completely dead within 3 hrs. In other plant species, these responses have been associated with the effect of ethylene, produced in response to lack of oxygen (Pratt, 1953; Jackson, 1984; 1985; Jackson & Drew, 1984; Raskin & Konde, 1984; Stead, 1985; Voesenek & Blom, 1989; Osborne, 1991;Reid & Wu, 1991; Brady & Speirs, 1991; Voesenek et al, 1992; Drew, 1997). Ethylene is known to accelerate premature senescence, defoliation and boll dehiscence in cotton (Hall et al, 1957; Kirzek, 1986), but the involvement of ethylene in cotton's response to waterlogging has not been demonstrated. AVG (aminoethoxyvinylglycine)is an inhibitor of ethylene production. It can be used to indicate the involvement of ethylene production in physiological processes. Improvements in commercial production of AVG provide an exciting opportunity to explore the importance of ethylene production in plant responses to waterlogging in the field. To achieve meaningful results, dose-response tests are necessary to establish the concentration of AVG that is high enough to inhibit ethylene formation while low enough to minimise nonspecific and possibly toxic effects to the plants from AVG itself(Jackson, 1991).