Variation of quality traits of storage root and their relationships with major agronomic traits in edible sweet potato

China is the largest sweet potato planting country and producer in the world. Sweet potato contains many nutritional elements which are useful for human health. The breeding of edible sweet potato with high quality and yield has become a major research goal for sweet potato breeders. The changes of quality traits of storage root during development and their relationships with major yield traits in three edible sweet potatoes [Ipomoea Batatas( L.) Lam] were studied. The starch content of edible sweet potato varieties showed an uptrend of"rise-fall rise"50-92 d after planting,slightly fluctuated afterwards,and increased as a whole. The soluble sugar and reducing sugar contents were similar,both contrary to the starch content 50-92 d after planting. The dynamics of starch content and dry matter content was similar in general. The crude protein content appeared similar trend to soluble sugar content,while total carotene content varied among three sweet potato varieties,following the order of Sushu 8 Xushu 23 Lizixiang. The starch content was positively correlated with fresh and dry weights of storage root. Daily growth rates of soluble sugar dry weight was positively correlated with fresh weight of storage root. And accumulation of soluble sugar was synchronized with the expansion of edible sweet potato storage root.