A new variety of summer-grown sweet potato reaching a sugar content of 42 °Brix [1] was showcased this month in Chiba City.
This development marks a significant shift in agricultural production because it removes the traditional need for post-harvest aging to achieve high sweetness. By utilizing selective breeding, growers can now provide exceptionally sweet produce during the summer months, a season when sweet potatoes are typically less available or less sweet.
The variety was unveiled during the “夏のさつまいも博2026” (Summer Sweet-Potato Expo 2026) exhibition held Aug. 8 [2]. The event featured more than 200 sweet-potato-based dishes [3], highlighting the versatility of the crop in various culinary applications. Among the offerings was a “芋づくし蜜芋ソフトクリーム” (honey sweet potato soft-serve) priced at 1,000 yen [4].
Industry experts noted that summer-grown tubers naturally accumulate more sugars, which leads to higher Brix readings. The new cultivar optimizes this natural process to ensure high sugar levels immediately upon harvest. Yoshitaka Sato, a representative of Gotō Shoten Sato no Imoya, said the crop has potential for year-round use.
“Sweet potatoes have a huge variety of processing options, and I think they are something that can be provided throughout the year,” Sato said.
Other participants at the expo included Kokoro no Moto, a yaki-imo shop from Hyogo. The shop has won the national yaki-imo grand prix three times [5]. Their presence at the exhibition underscored the commercial interest in diversifying sweet potato products beyond traditional winter snacks.
The expo served as a platform to demonstrate how breeding and processing can transform a seasonal staple into a consistent, high-value product for the Japanese market.
“A new variety of summer-grown sweet potato reaching a sugar content of 42 °Brix was showcased.”
The introduction of a high-Brix, non-aging sweet potato variety allows Japanese farmers to break the seasonal constraints of the crop's sugar development. By eliminating the curing period, producers can reduce storage costs and bring premium, high-sugar products to market faster, potentially stabilizing the supply chain for sweet-potato-based desserts and processed goods year-round.
