Abstract: 【Objective】 To analyze pollen viability and stigma receptivity of different Dahlia pinnata varieties,and to provide methods and a basis for parent selection in D. pinnata hybrid breeding. 【Methods】 Seventeen D. pinnata varieties were used as experimental materials. Among them,Genoa was used as a model variety for the screening of the pollen viability detection method and the optimization of the in vitro germination cultivation system. Then,pollen viability and stigma receptivity were compared,and finally hybridization experiments were conducted for validation. 【Results】 The in vitro germination method clearly showed pollen tube elongation in some of pollen grains,and could effectively distinguish viable from non-viable pollen. The optimal culture conditions were 25 ℃,3 h,and pH vaule 6.0,and the optimal culture medium was PEG 4000 20 g/L+sucrose 150 g/L+boric acid 50 mg/L+calcium chloride 80 mg/L. Among the 17 D. pinnata varieties,Genoa was a high-viability variety（germination rate≥50%）,and Lindsay Mitchell was a medium-viability variety（10%<germination rate<50%）. The tubular florets of Local Dahlia,Double Jill,Motto,Sir Alf,and Genoa showed extremely strong stigma receptivity,and all were rated as ++++. Two-way ANOVA showed that the main effects of pollen germination rate and stigma receptivity on seed-setting rate were extremely significant（P<0.001）. Double Jill×Genoa had the highest seed-setting rate（36.67%）,and Motto×Lindsay Mitchell was higher （31.67%）. 【Conclusion】 In D. pinnata hybrid breeding,materials with high pollen viability should be preferentially selected as male parents,and materials with extremely strong stigma receptivity should be used as female parents. The combinations Double Jill×Genoa and Motto×Lindsay Mitchell can improve hybrid success rates and are better parental combinations.

Key words: Dahlia pinnata, Variety, Pollen viability, Stigma receptivity, Hybridization