Abstract: A novel type of mutant of planetree (Platanus occidentalis L. ), which was produced via γ-ray irradiation, does not form lower buds yet its vegetative organs grow normally. Genetic analysis showed that this was clue to the deletion of DNA fragments in the mutant genome. Through genomic subtraction technique, a 2.0 kb DNA segment (pBS 2.0) was isolated, which is only present in wild planetree genome, but is absent in mutant genome.

Key words: Genomic subtraction, Deletion mutant, Platanus occidentalis