Direct Regeneration from Leaf Disc Explants of Peanut: Grafting Improves Survival Rate
Keywords:Grafting, In vitro regeneration, Leaf disc, Naphthalene acetic acid, peanut.
Leaf discs of 0.5 cm diameter from 10 days old seedlings of four peanut cultivars were cultured on Murashige and Skoog (MS) medium supplemented with twelve different combinations of Thidiazuron (TDZ) and Naphthalene acetic acid (NAA). The highest number of responding explants (52.67%) with the highest number of shoot buds (5.65) per responding explant was achieved at a combination of 0.5 mg/l NAA and 0.5 mg/l TDZ. The explants were then shifted to fresh MS medium containing 8 mg/l Benzylaminopurine (BAP) and 0.5 mg Indole Acetic Acid (IAA) for shoot elongation. Root induction was highest (56.07%) at half-strength MS medium supplemented with 1.5 mg/l NAA. Grafting of in vitro regenerated shoots on 10 days old seedling rootstock showed highest (61.30%) success rate. The survival rate of plants obtained from grafting was almost double (45.76%) than those achieved by rooting of shoots (22.41%). There was significant variation among four varieties regarding the number of responding explant, the number of shoots per explant, rooting or grafting percentage and survival rate. Golden proved to be the best variety in terms of the number of plants reaching maturity.