Twenty-five strains of disease repressive bacteria (DRBs) from an industrial collection were examined in greenhouse tests on 15 cotton genotypes that varied in possession of multipleadversity resistance (MAR) characteristics. Positive interactions (based on ANOVA) occurred between certain genotypes and DRB isolates, and these interactions were more frequent within the MAR types as compared to the semi-MAR or non-MAR types, suggesting some preferential mechanism exists for enhancing the DRB strains. Genotype rankings based on positive interactions were intermediate to their corresponding parental lines, suggesting inheritance of a mechanism that encourages the interaction to occur. For example, genotype T8-27, ranked as No. 12, was derived from a cross between SP-37 (a MAR cultivar ranked No.8) and DES-56 (a non-MAR cultivar ranked No.15). The repression of seedling disease pathogens on MAR types as compared to non-MAR types, and associated with certain DRB treatments, occurred in the presence of high pathogen counts and suggests that pathogens may be neutralized or prevented from causing disease rather than killed by a "factor" of MAR plus specific DRBS. A few genotype by DRB interactions were evaluated in 1991 AR field trials.