Novel strategy for maintenance and mass multiplication of gynoecious line in bitter gourd through micropropagation

This study was undertaken to standardize an efficient protocol for in vitro mass multiplication and maintenance of bitter gourd gynoecious line for its use in hybrid seed production. The apical bud gave better response than nodal segment for culture initiation. Murashige and Skoog (MS) basal medium supplemented with 6 benzyl-amino purine (2 mg/l) + α-Napthalene acetic acid (0.2 mg/l) was found best for in vitro survival (81.3%) in plantlets raised through nodal segment, while it was 77.84% in apical bud. The minimum duration (5.53 days) for bud sprouting was recorded for apical bud. Medium combination MS + BAP (1.0 mg/l) + IBA (0.1 mg/l) + GA₃ (0.3 mg/l) was found best earliest shoot proliferation (11.9 &14.62 days for apical bud and nodal segment). The apical bud and nodal segment regenerated 4.77 and 3.56 shoots/explant, respectively on the same medium. Elongation of microshoots was achieved maximum with MS + GA₃ (1 mg/l). The micro-shoots were rooted on full-strength MS medium supplemented with GA₃ (1 mg/l) + activated charcoal (100 mg/l). Minimum days were recorded for rooting (10.81) for apical bud and 11.49 days for nodal segment. The percent survival (81.25%) was maximum in glass jar with PP cap in the shoot tip derived plantlets, which was at par with the nodal segment (80.94%). Rooted plants were acclimatized in the greenhouse and subsequently established in soil. The protocol developed for this study led to an alternative for easy maintenance and use in gynoecious inbred development in bitter gourd.