Somatic embryogenesis and its conver- sion into plantlets in a multipurpose bamboo, Dendrocalamus hamiltonii Nees et Arn. Ex Munro

Abstract

New sprouts from the nodal segments of the fieldselected, mature, elite bamboos were used for the induction of embryogenic callus. Murashige and Skoog medium with BA and 2,4-D (1.0 mg/l each) was essential for culture establishment and callusing. Subsequently, elimination of 2,4-D and a corresponding increase in BA concentration induced embryogenesis. Upon transfer to sucrose -enriched medium without PGRs, these embryos matured and germinated into plantlets within 21 days, with a conversion rate of about 80%. The protocol thus established showed a low frequency of albinos when embryos were matured on a high sucrose (8%) containing medium under diffuse light conditions (5 μmol m –2 s –1 ). Rhizome formation took place upon prolonged culturing in the same medium and served as excellent propagules for multiplication. The plantlets were hardened and up to 78% survival rate was achieved in soil under greenhouse conditions. BAMBOOS form the backbone of rural economy of many southeast Asian countries. In recent years, bamboos have become important in social forestry programmes due to their short rotation cycles, fast growth and the possibility to be progressively harvested on a sustainable basis. Dendrocalamus hamiltonii is one such species which is popular for its strong culms that are used as structural support in local buildings, and the leaves serve as nutr itive fodder for milch cattle during winter months. Natural regeneration is dwindl ing due to the anthropogenic pressure on the local habitats. The traditional propagation method by ‘offsets’ limits the number of propagules, and even use of nodal segments for propagation is cumbe rsome and labour-intensive for large-scale establishment of bamboo plantations. Therefore, it is imperative to adopt alternative methods for rapid multiplication, and tissue culture techniques come handy. Although multiple shoot formation is accomplished with comparative ease, rooting of such shoots is still incon sistent in D. hamiltonii, and only up to 25–30% shows rooting 1 . In this con