Sucrose utilization and reducing sugar appearance during in vitro tuberization were studied in seven potato genotypes. The genotypes showed significant differences in the rate of sucrose utilization and the appearance of reducing sugars per 40 ml of microtuber induction medium over 60 days of incubation. As high as 60 per cent sucrose was utilized from the medium during in vitro tuberization. No quantitative relation could be established between sucrose utilization and reducing sugar appearance in the medium. Increased sucrose utilization resulted in an increment in average microtuber weight and microtuber yield. The rate of sucrose utilization did not have any influence on micro tuber number. The study showed that sucrose was mainly responsible for bulking rather than for induction of microtubers.
