Climate change impacts
As a result of global warming, Citrus unshiu (mikan) are increasingly subject to delayed peel pigmentation, peel puffing, and damage during storage. In recent years, shipments have had to move forward due to global warming, and while some shipments are taking place in December, there has been shortages in March shipments, which has led to requests from the market to secure shipment volumes. However, as mentioned, March shipments have suffered from deterioration while in storage.
Adaptation activity
The Shizuoka Prefectural Research Institute of Agriculture and Forestry has selected a new S1200 mikan variety to address these issues, and there are high expectations that the variety will become popular among producers. The new "S1200" is a very late-season variety, taking about one month more for its peel to color than the conventional "Aoshima Onshu", and is therefore harvested a month later, it is also characterized by less peel puffing (Fig. 1). Previous studies have shown that the new S1200 variety can be stored until April in conventional storage containers, as it is harvested in the second half of December. In addition, the citric acid content is slightly higher, enhancing its suitability for storage. Producers, agricultural cooperatives, wholesalers, prefectural authorities, and other relevant organizations are working together to promote the new variety. In addition, blue LED and ultraviolet light sources are being developed, which have been confirmed to suppress the growth of blue mould, and to decrease the rate of decay for fruit in storage, as a way to improve storage efficiency (Fig. 2).
Outputs / Expected benefits
The development of new varieties and technology to combat higher temperatures is expected to reduce the impact of rising temperatures on the cultivation of mandarins.
