Macro- and Micropropagation of Plants for Income Generation

Abstract

The present chapter focused on the development of the macro–micro multiplication system of three economically important plants in silviculture (Rattan palm—Calamus thwaitesii), agriculture (Banana cultivars), and medi-culture (‘aromatic ginger’—Kaempferia galanga) for consistent production, sustainable utilization, and income generation. In C. thwaitesii, macro multiplication is through seeds and suckers, while micro multiplication is accomplished by somatic embryogenesis, axenic seedling culture, and shoot tip derived offshoot culture. For somatic embryogenesis, zygotic embryos cultured in Murashige and Skoog (MS) medium supplemented with 7.0 mgL−1 2,4-dichlorophenoxyacetic acid (2,4-D) induced semi-friable calli which transferred in the same medium augmented with 0.5 mgL−1 6-benzylaminopurine (BAP) and 0.2 mgL−1 α-naphthaleneacetic acid (NAA) induced ~12 discrete globular embryoids in 6 weeks. The isolated embryoids in hormone-free medium yielded 65% plantlets. The embryoids and axenic shoots thus obtained exhibited maximum shoot induction in a medium supplemented with 0.1 mgL−1 Thidiazuron (TDZ). The shoot initials after subculture in medium supplemented with 0.4 mgL−1 BAP and 0.1 mgL−1 TDZ produced shoot proliferation followed by elongation in basal medium. The elongated shoots produced roots in medium supplemented with 3.0 mgL−1 naphthaleneacetic acid (NAA). With this established protocol, ~5940 rooted plantlets could be harvested after 40 weeks from a single embryoid. Similarly, axial shoots were induced from the shoot tip of C. thwaitesii suckers on MS medium supplemented with 0.4 mgL−1 BAP and 0.1 mgL−1 each of TDZ and NAA. The shoot initials obtained were transferred to fresh medium of the same composition for shoot multiplication, and such multiplied shoots were transferred to ½ MS hormone-free medium for shoot elongation. The elongated shoots (5–7 cm) were then transferred to 3.0 mgL−1 IBA/4.0 mgL−1 NAA to raise plantlets. The plantlets thus obtained were hardened in a mist house for 8 weeks, then to 50% shade house for another 16 weeks and the well-established 6-month-old nursery plants reintroduced to selected forest segments exhibited 79–86% field establishment even after 3 years of observation. Thus, the mass multiplication system developed in C. thwaitesii ensure a continuous supply of quality planting material to the cane-based cottage industry.