Abstract: As a short\|day plant， most of sweetpotato varieties cant naturally bloom in northern area of China under the long time light. In order to overcome this obstacle， a combination method of grafted and short\|day treatment was usually used to promote the sweetpotato flowering and fruiting. In this study， three different rootstocks， two grafting methods and two sun light treatments were used to study the affinity of different rootstocks and grafting methods and the impact on sweetpotato flowering and fruiting. The results showed that the sweetpotato diploid wild species （Ipomoea crassicaulis） was the best rootstocks， which not only had a wide range of affinity， but also can significantly improve the flowering and fruiting of sweetpotatos. Thus it can save the cost of breeding and improve breeding efficiency.

Key words: sweetpotato, wild species, graft, rootstocks