Asian Research Journal of Agriculture

Aims: The present work was carried out to break dormancy of microtuber from storage environment for seed potato multiplication as well as regulating their future use.

Study Design: The experiment was laid out in a completely randomized design with three replications.

Place and Duration of Study: The experiment was conducted in the Tissue Culture Laboratory of Bangabandhu Sheikh Mujibur Rahman Agricultural University, Salna, Gazipur, Bangladesh during the period of September 2010 to February 2011.

Methodology: The experiment having two factors. First factor; microtuber weight which are graded as S₁ = >500 mg, S₂ = 250-500 mg, S₃ = <250 mg and second factor; seven levels of GA₃ viz. G₁= 0.0 mg L^-1, G₂ = 25 mg L^-1, G₃ = 50 mg L^-1, G₄ =100 mg L^-1, G₅ =150 mg L^-1, G₆ =250 mg L^-1, and G₇ = 500 mg L^-1. To determine the most effective level of GA₃ were applied on graded fresh microtuber that had been cold-stored at 4-5°C for 6 week. Sprouting was monitored every 2 days’ interval. Microtubers per treatment were soaked in different concentration of GA₃ for 24 h in the light, and then placed for incubation under 16/8 h d/n cycle.

Results: The lowest number of days (13) was taken to induce sprout in case of heavier microtuber and highest number of days (20.44) required for sprouting of smaller microtuber when 500 mg L^-1 of GA₃ was used. Microtubers exposed to lower concentrations of GA₃ exhibited short length sprout. The trend of fresh weights of sprouts decreasing with the decrease of microtuber weight. The microtubers of >500 mg grade produced more sprout mass unit^-1 length of sprouts than other two grades.

Conclusion: Microtuber <250 mg has longer periods of dormancy than larger microtubers and breaking their dormancy, 500 mg L^-1 GA₃ showed superior performance.