Abstract: Paeonia rockii is considered to be one of the main progenitors of Chinese tree peony cultivars,and hybridization is likely to be the most important way for incorporation of genetic composition of Prockii.However,no molecular evidence has shown relatedness of woody peony cultivars to Prockii so far.In this study,Prockii was used as a maternal parent crossing with other three Chinese woody peony cultivars (Psuffruticosa ‘Hai Tang Zheng Rong’,Psuffruticosa ‘Yan Zhi Hong’ and Psuffruticosa ‘Sheng Dan Lu’)  as paternal parents.The relationships between the F1 hybrids and their parents were analyzed using ISSR (Intersimple sequence repeat) markers.Our results showed that ISSR fragments present in both parents were detected in the genomes of the F1 generation.Therefore,it is possible that some Chinese woody peony cultivars with a large blackpurple blotch at the lower part of petals originated through hybridization with Prockii as a parent.Our results also suggest that ISSR markers are useful for identification of hybrids and classification of cultivars.

Key words: Paeonia rockii；Psuffruticosa；Hybridization；ISSR Marker；Cultivar identification