Effect of Growth Regulators on Meristem Culture and Plantlet Establishment in Sweet Potato ['Ipomoea Batatas' (L.) Lam.]

Sweet potato shoot apical meristems with 1-2 leaf primordia were aseptically isolated and cultured on liquid or solid Murashige and Skoog (MS) medium supplemented with different plant growth regulators. Primary shoot induction was most effectively promoted by liquid MS medium supplemented with 2.0 mg/l Kn plus 0.5mg/l GA 3. In this combination about 75% of excised meristems responded with an average vigor of 0.79. The shoots were regenerated without intervening any callus formation. The use of TDZ or BAP produced callus instead of shoot development and therefore not recommended for meristem culture. Following primary establishment, the primary shoots were further cultured on semisolid MS medium supplemented with 2.5mg/l Kn+0.5mg/l GA 3 for proper shoot growth. The developed shoots were further micropropagated by node cutting. For optimal micropropagation by node cutting, MS medium supplemented with 3.0mg/l Kn+0.5mg/l GA 3 was most effective. More than 75% of these micropropagated plantlets were successfully established and showed new leaf development under soil condition. This optimized meristem culture technique would be useful for developing uniform and virus-free clones of sweet potato in which viral diseases are predominant.