Thermal unit use efficiency during growth and sucrose accumulation in sugarcane

Thermal unit use efficiency (°Cd) during growth and sugar accumulation in sugarcane varieties, representing high and low sucrose content was examined in a field experiment for two years. Leaf and stem development during the early and grand growth phases utilized 1684°Cd in 1986–87 or 1860°Cd in 1987–88 seasons, while during the maturity periods the corresponding values were 1062°Cd in 1986–87 and 1090°Cd in 1987–88. Varieties Co 7712, Co 7704 and CoC 671 which had high sucrose % juice at harvest (> 20.0%) had also positive and significant correlation with accumulated thermal units (r=0.8738**) while in low sugar (<17.0%) varieties the correlation was r=0.7986**. High ratios of sucrose/°Cd suggested a greater thermal unit use efficiency (TUE), particularly in high sucrose containing varieties.