Harmonal effect on multiplication of Solanum tuberosum L.

In vitro culture techniques may be used for the biotechnological advancement of this plant. Although NAA induced somatic embryos upto heart shaped stage, recovery of plantlets were not possible. 3 per cent sucrose was found optimum for somatic embryogenesis. Developmental stages of somatic embryos were almost similar to zygotic embryogenesis of dicotyledons. Histological observation showed initiation of somatic embryos from the deep region below the epidermal layer of explants. Complete plants were recovered in the first subculture containing same concentration of 2.4-D. A protocol for the induction of direct shoot organogenesis was developed from leaf explants. The two hormone combination tested, NAA and Kn favoured for the callus mediated shoot initiation while NAA and BAP supported direct shoot regeneration. Maximum response of shoot multiplication was noticed with sucrose (3%) and commercial cane sugar was also equally good. Histological studies revealed the differentiation of meristemoids in the deep layer of cells and participation of epidermal cells above the meristemoid in the organization of shoot. BAP 0.5 mg/1 was found suitable for optimum growth and elongation of shoot. Rooting was best in half-strength MS medium with 1.0 mg/1 IBA. Among the two kinds of incubation conditions adopted for hardening of regenerated plants, unsterilized soil substrate, ordinary water and incubation under shade conditions gave maximum success.