Effect of Genotypes and Plant Growth Regulators on in vitro Morphogenesis in Muskmelon (Cucumis melon L.) From Cultured Mature Cotyledons

Mature cotyledons of four cultivars of Cucumis melon were cultured on twenty different fortifications of MS media to assess their in vitro response. Higher in vitro morphogenesis leading to plantlet regeneration was varied considerably due to genotypes and inoculation medium. Culture medium MS2D (MS + 2.0 mg/l 2,4-D + 30.0 g/l sucrose + 7.5 g/l agar) proved well for callus initiation. Inoculation medium MSD.5B (MS + 1. 0 mg/l 2,4-D + 0.5 mg/l BA + 30.0 g/l sucrose + 7.5 g/l agar) induced direct somatic embryogenesis and average number of somatic embryo per explant in higher frequencies. Culture medium MS2D.5B (MS + 2. 0 mg/l 2,4-D + 0.5 mg/l BA + 30.0 g/l sucrose + 7.5 g/l agars) enhanced the frequency of indirect somatic embryogenesis and organogenesis. Nutrient medium MS2NB (MS + 2.0 mg/l NAA + 0.5 mg/l BA + 30.0 g/l sucrose + 7.5 g/l agar) promoted direct organogenesis and plantlet regeneration from direct organogenesis. Medium MS.5B.5Kn.5N (MS + 0.5 mg/l BA + 0.5 mg/l Kn + 0.5 mg/l NAA + 20.0 g/l sucrose + 7.5 g/l agar) regenerated plantlets in higher numbers via somatic embryogenesis and indirect organogenesis. Among the cultivars, Pusa Madhuras was found significantly superior followed by Local, Durgapura Madhu and RM-50 for all culture phases.