Temperature and Photoperiod Effects on Tuber Production and Specific Gravity in Diploid Potatoes

Abstract Tuberization response, average number of tubers produced per tuberized plant, total tuber yield, average tuber weight, and average tuber specific gravity were measured for six diploid potato clones grown under long and short day conditions at 22°/18°C and 18°/14° in the phytotron. Average number of tubers and total tuber yield were significantly greater under short days than under long days. Significant temperature × photoperiod interactions were found for these two variables. Lack of significant photoperiod, temperature, and photoperiod × temperature effects on average tuber weight suggests that significant increases in average yield occur due to an increase in the average number of tubers produced and not to an increase in the size of individual tubers. Average tuber specific gravities were significantly greater at 18°/14° than 22°/18°. A significant temperature × photoperiod interaction was found for this variable.