Case Study on Varietal Mixed Planting as an Option of Variety Use in Sugarcane in Tanegashima

摘要

In Tanegashima, a southwestern island of Japan, where sugarcane production is limited by low temperatures and frost (Hayashi, 2011), cane growers have traditionally relied on specific superior varieties such as NCo310 or NiF8, and are currently obliged to choose from a limited selection, including NiF8, NiTnl8, and Ni22 (Fig. 1). NiF8 is a dominant variety with poor adaptability to low temperatures but high tolerance to the main sugarcane diseases. Although the area cultivated for NiF8 is gradually reducing, that for NiTnl8 is increasing because it tolerates low temperatures and yields are high even without mulching; however, due to its high elongation ability, disorderly lodging often occurs in strong winds (Terajima et al., 2010). The growing area of Ni22 is also increasing slightly because the variety has a high ratooning ability, tiller number, and sugar content, although it is not so vigorous in a new planting (Irei et al., 2010). Thus, each variety has both advantages and disadvantages.