Abstract
Colchicine was applied directly t.o ant.hers excised from thc flower buds of tobacco (.Nicotiana tabacu.m I..) just before the initiation of anther culture, and dip]oidization and development of microspores in thc colchicine-t, reated anthers were investigated. Anther culture response, which was defined as the percentag'e of anthers producing plant lets to the tot.al number of cultured anthers, decreased with the increase in both colchicine concentration and treatmont duration. However, high frequenciGs of diploid plants were obtained among tho plants derived from t.he anthers treated with colchicine. In particular, the hig'hest diploidizat.ion rat.e (66.7% ) was. obtained in the 0.4 % colchicine treat-ment for 8 h. Furthermore, neither ploidy chimera nor growth damage appeared in the generated plants.
