Optimization of growing conditions, substrate-types and their concentrations for acclimatization and post-acclimatization growth of in vitro-raised flame lily (Gloriosa superba L.) plantlets

Majority of tissue culture-raised flame lily (Gloriosa superba L.) plantlets do not thrive following their transfer from in vitro conditions to in vivo field conditions. Such plantlets need to be acclimatized with high survival rate in order to ensure the availability of quality planting materials so that supply of colchicine can be sustained. In this study, various factors viz. different tenures of acclimatization (2 weeks, 3–6 weeks, 7–10 weeks, 11–14 weeks, and 14 weeks), and different potting mixtures [such as (a) sterilized vermiculite + sterilized soil at culture room; (b) garden soil : sand : vermiculite; 2:1:1 under shade in net-house (SNH); (c) garden soil : sand : farmyard manure; 2:1:1 potted plants in direct sun light (DSL); (d) garden soil : sand : farmyard manure; 2:1:1 potted plants in DSL; (e) field-transferred plantlets after 3rd week in experimental field/home garden under DSL] were optimized to obtain maximum growth responses during in vivo acclimatization of G. superba. Amongst all the tested growth parameters, the SNH (b) condition was found to be the most suitable in terms of survival rate (100 %), followed by 60.71 % in natural habitat (a, c–e). In contrast, plantlet height (~ 146 cm) and number of shoot/plantlet (~ 14) were highest in natural habitat (a, c–e) followed by SNH (b) condition that exhibited lower plantlets height (~ 10 cm) and less number of shoots/plantlet (~ 3). Present study reports a successful acclimatization protocol for this medicinal herb to ensure its maximum in vivo survival eventually to meet the demand of large-scale quality propagules as a sustainable source of colchicine.