Micropropagation of tetraploid watermelon is important to cope with high cost of seed. Seeds of tetraploid watermelon were grown in vitro to raise seedlings. Hypocotyl and cotyledonary explants and media supplemented with plant growth regulators (BAP and NAA) was explored for callus induction and organogenesis. Data was collected for callus, shoot and root induction. Maximum callus induction was observed at BAP 5 mgL-1 (76.66%) from cotyledon and (73.33%) from hypocotyls explant. The callus induced from different explants was sub-cultured on the shoot regeneration medium. Higher shoot induction (96.66%) was observed from cotyledon and hypocotyl explant (76.66%) on MS + 1.0 mgL-1 BAP + 0.2 mgL-1 NAA with maximum number (6.3) of shoot per explant and average shoot length 4.5 cm. Among different types (NAA and IAA) and concentrations (0, 0.1, 0.3, 0.7, 1.0 mgL-1) of auxins investigated for root induction, maximum frequency of rooting was observed in 0.1 mgL-1 NAA while no root formation was observed at higher levels of auxin (1.0 mgL-1). Similarly in case of number of roots per shoot maximum root (4.3) was obtained on MS medium supplemented with 0.1 mgL-1 NAA. Key Words: Regeneration, Explant, Tetraploid, Water Mello
