Influence of Photoperiod and EDTA Salts on Endogenous Gibberellic Acid Concentration of Tissue Culture Grown Potato Microplants

Kufri Bahar, a leading potato variety is facing a problem of deshaped elongated tubers. Deshaping of tubers in form of elongation with jelly end formation leads to spoilage during transportation and storage. This elongation may be due to the stress conditions and/or enhanced gibberellic acid (GA) formation during micropropagation. Photoperiod and EDTA salts are reported to influence the GA concentration. Therefore, the effect of photoperiod and EDTA salts was investigated on the endogenous GA concentration of tissue culture microplants of potato vars Kufri Bahar and Kufri Lauvkar. The GA concentration in microplants grown in tissue culture media with Na-EDTA, Fe-EDTA and without EDTA ranged from 0.84 to 1.95 nmol/ml FW (fresh weight). In the present study, no correlation was observed between EDTA and GA concentration. Shoot length, internodal distance and number of nodes were more in microplants grown under a long photoperiod (16 h). Root length, number of roots and the number of leaves were high in short photoperiod (12 h) grown microplants. Gibberellic acid content showed similar trend as that of shoot length and ranged from 0.65 to 1.49 nmol/ml. Concentration of GA was more in var. Kufri Bahar compared to var. Kufri Lauvkar under the long photoperiod, which showed that Kufri Bahar is more responsive to photoperiod. High GA content in var. Kufri Bahar microplants grown under the long photoperiod could be the possible reason for tuber elongation. Therefore, to avoid the deshaping of tubers, the photoperiod during in vitro propagation may be shortened, particularly for var. Kufri Bahar.