Control of root and shoot‐bud formation from potato tuber tissue cultured in vitro

Comparative studies on the control of root and shoot‐bud formation and plant regeneration have been undertaken in discs (1 × 6 mm in diameter) excised from tubers of potato (Solanum tuberosum L. cv. Irish Cobbler) cultured in vitro. The results clarified that the optimal culture conditions for shoot‐bud formation were quite different from those for root formation and, in conclusion, that (1) shoot‐buds were produced when cultured in modified White's medium containing 0.25 M mannitol with 2.3 μM zeatin and 0.57 μM indole‐3‐acetic acid (IAA) at 20°C under relatively high light irradiation, while (2) roots were readily formed when cultured in modified White's medium containing 29 mM sucrose with 4.7 μM kinetin plus 1.7 μM IAA at 30°C in darkness.