Abstract: Three potato （Solanum tuberosum L.）varieties, namely Atlantic, Eugene, and Holland, were used as materials to determine the starch content in tubers of different diameters and analyze the relationship between starch content and tuber diameter. The results showed that the amylopectin content of the three tested potato varieties was significantly higher than the amylose content, indicating that amylopectin was the dominant starch type, and the cortex was the main storage site for starch. The tuber diameters corresponding to the accumulation peaks of amylose and amylopectin contents in different parts of the three varieties were different. Before the peak, the starch content increased with the increase of tuber diameter. Except for individual cases, the differences in starch content between different diameter grades of tubers reached a significant level, showing a linear growth trend with a good correlation. The tuber starch content of atlantic was the highest, and the correlation with tuber diameter was the best , so it could be used as a key object for studying the variation law of potato starch content. Meanwhile, according to the variation law of starch content in tubers of the three varieties, it was concluded that there was a positive correlation between starch growth rate and starch content.

Key words: potato（Solanum tuberosum L.）, starch content, tuber diameter, medulla, cortex, change