Abstract: The combining ability and genetic parameters were estimated for 7 ornamental characters in F1 progenies of 12 cross combinations of chrysanthemum（Dendranthema × grandiflorum）hybridized by using a 3 × 4 incomplete diallel cross design（NC II）with three cut-chrysanthemum cultivars as female parents and four potted chrysanthemum cultivars as male parents. The results showed that：（1）Flower diameter，ray floret number and ray floret length were controlled mainly by additive gene action，while plant height and leaf length were controlled principally by non-additive gene action. In addition，leaf width and ray floret width might be controlled both by additive and non-additive gene action.（2）‘Zaoyihong’ had a positive general combining ability（GCA）effect for the 7 ornamental characters involved herein，and‘Hereby’could be used as an important parent in hybridization breeding program aiming for preferable double flowers. The three cross combinations，i.e.‘Hereby’בYumantang’，‘Qingxinhong’בZaoyihong’and‘Hongqueshe’ב03-11-2’，performed quite well special combining ability（SCA）regarding mostof the 7 ornamental characters.（3）Variance of population combining ability and its contribution to hybrid progenies suggested that there was a maternal heredity effect for all the ornamental characters studied except ray floret width. The heritability in broad sense（h2B）of the 7 characters ranged from 59.56%（ray floret width）to 80.40%（ray floret number）. The heritability in narrow sense（h2N）were lower than 50% except ray floret number amounting to 80.40%. These indicating that ray floret number belonged to high heritability characters and selection pressure should be increased for this character in earlier selection.

Key words: chrysanthemum, combining ability, heritability, incomplete diallel cross, ornamental character