Macro- and Micropropagation of Plants for Income Generation

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AbstractThe 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.Similarly, the propagation of banana cultivars plays a major role in the agriculture business. It involves macro–micropropagation methods for the supply of quality planting materials. Macropropagation is a very slow method of multiplication that consists of decapitation, decortications, and hardening, which produce only 50–60 shoots per sucker in 4–5 months. Therefore, the expectation of mass multiplication through micropropagation of bananas is very high. In the case of micropropagation of banana cultivars, usually full-strength MS medium supplemented with different concentrations of cytokinins particularly BAP (1–5 mgL−1) is sufficient for culture initiation and multiplication. The shoot bunches thus obtained were transferred to hormone-free MS basal medium for root formation. The hormonal concentration may vary according to the variety of bananas.Furthermore, macro–micro multiplication methods of the highly priced, medicinal and aromatic plant Kaempferia galanga is also demonstrated here for large-scale production, supply, and income generation. Macropropagation is carried out through rhizomes which remain dormant during drought, and they sprout 2–4 plants per rhizome in a year during the onset of spring which is uneconomic. Therefore, micropropagation has given more importance to this species. For micro multiplication, its axillary buds along with basal rhizome part (1 cm) were implanted on MS medium supplemented with 0.5 mgL−1 BAP to induce 1–3 shoots within 30 days. Single shoot isolated from such cultures and subcultured on medium supplemented with 4.0 mgL−1 BA along with 1.0 mgL−1 each of Kinetin and IAA produced an average of 30 shoots after 60 days of culture. Shoot elongation and rhizogenesis were parallel with shoot multiplication irrespective of the hormonal treatments. The roots developed were green and thick, and the number varied from 4 to 8. The rooted plants were hardened in the mist house (28 ± 2 °C, 80 ± 5% RH) for a period of 1–2 weeks and then to a shade net house for 3–4 weeks before transplanting. The plantlets after the short hardening phase transplanted in polybags showed 90–95% survival. Such established plantlets when transferred to the field during southwest monsoon rains facilitated better establishment at 80–90% rate. They showed normal growth like the field-grown plants in their yield and rhizome formation. Thus, the viable highly reproducible propagation systems demonstrated here can be used for the sustained delivery of high-quality planting materials to the beneficiaries thereby creating employment opportunities and income generation to some extent.Keywords Calamus thwaitesii Banana cultivars Kaempferia galanga MacropropagationMicropropagationEmbryoidsAxenic shootReintroduction