Shoots of haploid,diploid and tetraploid sharing the same genome were cultured in medium and their response of rooting to the composition of the culture medium was investigated.It was found that in medium without growth regulators,shoots of haploid could initiate roots quite efficiently with the shortest time required for the emergence of roots and with the highest rooting rate; the response of diploid was similar to that of haploid and largely different from that of tetraploid,which obviously required longer time for initiation of roots and had the lowest rooting rate.Supplement of naphthalene acetic acid (NAA) at 0.05 and 0.15 mg/l or indole-3-butyric acid (IBA) at 0.1 and 0.3 mg/l to the medium had only a little positive effects on the rooting of diploid shoots and in some cases had even negative effect on the rooting of haploid shoots,but enhanced effectively the rooting of the tetraploid.By supplementing IBA at 0.3 mg/l to the medium,the time required for the emergence of roots of the tetraploid shoots was shortened and the rooting rate was increased largely,and as a result,healthy tetraploid plantlets with fully developed root system could be efficiently propagated.