Abstract: This paper analysed genetic variation of rooting characters in the new clones of the Aigeiros section. The results indicated that there are highly significant differences in the earliest date of rooting, number of main roots, sum of the lengths of main roots and number of lateral roots in 1-69 poplar × Simon poplar F1 clones and 1-69 poplar × Nigra poplar F1 clones. No great changes took place in heritabilities of rooting ability at varying dates after water culture, which indicated that the rooting ability of these clones was not sensitive to environmental conditions. The dynamic changes of sum of the length of main roots was approached by index curve, which could distinguish the rooting characteristics of various genotypes.