Abscission is an important physiological process that limits yield and indirectly affects fiber quality in cotton. In an attempt to identify genes associated with abscission in cotton, a cDNA library with a titer of 10⁷ pfu/ml was established in the Uni-Zap XR vector. The cDNA library was produced using mRNAs extracted from petiole abscission zones of ethephon treated seedlings. An additional abscission subtracted cDNA library with 2124 individually isolated recombinant cDNA clones was constructed. Randomly selected clones from the subtracted cDNA library were excised in vivo and plasmid DNAs of 42 clones have been analyzed by dot blot. The nylon membranes containing DNAs from the 42 different isolates were probed with ³²P labelled first strand cDNA prepared from abscission zone mRNAs of both treated and control tissues. DNA dot blot hybridization showed that all 42 clones are induced in the abscission zone. Northern analysis and DNA sequencing are in progress to identify the cDNA clones and study expression of these genes in abscission zone tissues.