2019 Volume 12 Issue 1 Pages 16-22
Effective utilization and maintenance of sugarcane varieties are important for realizing sustainable, stable and high production. In this research, we collected statistical data and conducted questionnaire survey to clarify usage situation after release of the varieties. On the composition of varieties, there are many areas with more than 30% of one specific variety. Especially in Kumejima, Miyakojima, Tanegashima and Yoronto, where the risk of disease spread is higher due to higher ratio of ratoon area, diversification of used variety is required. In the southern part of the mainland Okinawa, Minami- and Kita-daitojima, Iheyajima, Amamioshima, Kikaijima, and Yoronto, the proportion of “other varieties” is as high as 20 to 40%, which is due to use of un-recommended varieties and mixed varieties. In addition, the questionnaire survey revealed that the benefits of utilizing multiple varieties, such as suitable varieties and risk diversification, are recognized. On the other hand, there are many problems of multiple varieties such as mixed varieties, complicated pulling seedling and seedling management, and too much number of varieties to select. Regarding mixed varieties, complementary planting for missing plant is considered to be a main reason, and it can be solved by enhancing planned seedling field and seedling beds for raising. In addition, it is necessary to print a handbook that both producers and extension stuffs can utilize and support efficient variety selection and composition without bias.
