Abstract: 【Objective】 The aim of this research is to define the edible quality index and to provide a basis for edible purple-fleshed sweetpotato breeding. 【Method】 The content of anthocyanin, dry matter, soluble sugar and reducing sugar in steamed root, and taste index were measured from 276 purple sweetpotato strains. In addition, the relationships between nutritional compositions and taste of steamed purple sweetpotato were analyzed. 【Result】 As the great variation coefficient of anthocyanin content, it is easy to screen high anthocyanin content varieties in purple sweetpotato breeding. It is the best method that ayamurasaki was crossed with non-purple-fleshed parents containing high sugar to improve the taste of filial purple-fleshed F1 generation of ayamurasaki. Reducing the group level of anthocyanin content would benefit to improve the breeding efficiency of edible purple-flesh sweetpotato. Even thoughanthocyanin content leass than 90 mg·100g^-1FW, there was still a good breeding efficiency of edible purple-flesh sweetpotato with high anthocyanin content. There was a better efficiency of edible purple-fleshed breeding when dry matter content ranged from 27.5% to 38%, whereas the best breeding efficiency for dry matter content was ranged from 32% to 36.5%. Moreover, increasing the group level of soluble sugar content in steamed root would help to improve the efficiency of edible purple-fleshed breeding. Anthocyanin content showed highly significant negative effects on sweetness and fragrance of purple sweetpotato, and its negative effects on taste up to 51.30% of taste incremental contribution from soluble sugar. Dry matter content was highly significantly positively correlated with texture, fragrance, and coarse fiber of purple sweetpotato, but it was highly significantly negativelycorrelated with viscosity, and was closely significantly negatively correlated with sweetness. Therefore, dry matter content was little influence on total taste. On the other hand, soluble sugar in steamed root showed a significant effect on taste of purple sweetpotato, in which soluble sugar content had a highly significantpositive correlationwithsweetness,viscosity and texture. Furthermore, non-reducing sugar content had more contribution to sweetness, fragrance, and texture than reducing sugar content, and the contribution to taste incremental from non-reducing sugar was 2.3 times than that of the reducing sugar content. Sweetnessoccupiedan extremely important positionin the taste evaluation ofpurple sweetpotato, and its contributionrate of taste increment was up to 55.38%.【Conclusion】The content of anthocyanin and soluble sugar in steamed root is an important index for edible purple-fleshed varieties.In conclusion, it should take into account both nutrition andfood quality in edible purple-fleshed breeding, and anthocyanin content should be controlledless than90 mg·100g^-1FW. The best way for traditional edible purple-fleshed sweetpotato breeding is to select purple-fleshed parent hybrid with high sugar-containing non-purple-fleshed parent.

Key words: purple sweetpotato, taste, anthocyanin, sugar, dry matter content