Plants of an obligate short day (SD) potato variety ‘Kufri Sindhuri’ grown in small pots were given three brief light exposures for 5 to 6 minutes, singly and its combination of the three at 4, 8 and 12 hrs after the commencement of 16 hr inductive dark period to study mainly the effects of light breaks on tuber initiation. Exposure of plants to a single light break was not effective, but the three hreaks given to the same plants suppressed tuber initiation. It appears that an uninterrupted dark period of greater than 4 hrs in 24 hrs cycle is essential for tuber initiation. The procedure of giving 3 light breaks at 4 hrs intervals in a dark period of 16 hrs, or possibly even less can be adopted in screening the genetic material for long day (LO) response, in place of 24 hrs light used at present.
