A new sweetpotato variety 'Michishizuku' for alcohol and starch production with high yield and resistance to foot rot.

We developed a new sweetpotato variety, 'Michishizuku', as the raw material for imo-shochu, a traditional Japanese distilled liquor made from sweetpotaoes, and for starch production. Michishizuku was selected from a cross between 'Konaishin' and Kyukei 09187-14 and was released in 2021. Its total yield was higher than that of 'Koganesengan', slightly higher than that of 'Shiroyutaka', and slightly lower than that of Konaishin. The starch content of Michishizuku was significantly higher than those of the other varieties, and its starch yield was 146-147% that of Koganesengan and 93-102% that of Konaishin. Shochu brewing tests confirmed that the alcohol yield of Michishizuku was higher than that of Koganesengan. In addition, the flavor of shochu made from Michishizuku (Michishizuku shochu) was similar to that of Koganesengan shochu, and its sensory evaluation score was slightly higher than that of Koganesengan shochu. Based on these results, Michishizuku is highly suitable for shochu brewing. The viscosity characteristics of the starch of Michishizuku were similar to those of Shiroyutaka and Konaishin, and its whiteness was as high as that of Shiroyutaka. Therefore, Michishizuku is also suitable as a raw material for starch production. Michishizuku exhibited moderately strong resistance to foot rot, which causes severe damage to sweetpotato in the Southern Kyushu area. These characteristics suggest that Michishizuku will contribute to reductions in damage caused by foot rot and the stable production of shochu and starch.