Influence of Bromoethane, Ethanol and GA(3) on Dormancy Breaking and Subsequent Tuber Yield of Several Potato Cultivars

Effects of bromoethane (BE), ethanol (EtOH), and gibberellic acid (GA(3)) applications were evaluated for dormancy breaking of potato (Solanum tuberosum L.) tubers under room condition. Seed size (30-50 g/tuber) tubers of potato cvs. Gogu Valley, Purple Valley, Bora Valley and Superior were used. In the case of single application of chemicals, higher concentrations of BE and GA(3) resulted in earlier days of sprouting and earlier days to 80% sprouting; in contrast, higher concentrations of EtOH delayed the sprouting. Among the evaluated chemicals and concentrations, BE (0.2-0.3 mL.L-1) showed the most desirable effect in breaking the tuber dormancy, which was about two times earlier than the untreated control. BE treated tubers also produced short and strong sprouts with the highest percentage of sprouted eyes in both of the tested potato cvs. Gogu Valley and Purple Valley. In the other experiment, double application of BE (0.2 mL.L-1) at 24 h interval, and combined application of GA(3) (200 mg.L-1) and BE (0.2 mL.L-1) showed significant effect on breaking the tuber dormancy with high percentage of sprouted eyes and medium-length multi-sprouts; whereas, tubers treated with GA(3) alone produced long sprouts with few sprouted eyes in medium dormancy (Superior) and lone dormancy (Bora Valley) potato cultivars. Tubers treated with. BE (0.2 mL.L-1) alone or combination of GA(3) (200 mg.L-1) and BE (0.2 mL.L-1) treatment showed the most number of main sterns and higher tuber yield in the Subsequent Cultivation Under Field condition without any morphological changes ill tuber and plant characters. Thus, the double application of BE (0.2 mL.L-1) or combined application of GA(3) (200 mL.L-1) and BE (0.2 mL.L-1 is recommended for breaking dormancy of freshly harvested potato tubers in diverse potato cultivars.