Sugarcane production in Japan dropped to a record low of 1,186,000 tons in 2004. Severe drought and tropical storms (typhoons) often reduce sugarcane yields. In order to avoid these environmental stresses, an early harvest system and early maturing cultivars are required. The maturing characteristics of one early maturing clone (“KY96T-547”) were thus investigated in breeding experiments to clarify effective methods of identifying early maturing clones. The results of spring planting crops in a regular breeding program and autumn planting crops intended for early harvest were also analyzed. Among the spring planting crops, the early maturing clone exhibited earlier increases in brix value at the top position of the stem, with higher orders of brix for this clone also being observed at the top. The coefficient of variance for the top brix among approximately 50 clones was higher than that for other stem positions. The coefficient of variance was higher at the beginning of October, when the brix values of early maturing clones increased. This is the best time for screening at the research site . Among the autumn planting crops, the early maturing clone matured October or November at the same level as in the regular harvest season.