Biology and biotechnological aspect of sweet potato (Ipomoea batatas L.): a commercially important tuber crop.

MAIN CONCLUSION: This review highlights the economic importance of sweet potato and discusses new varieties, agronomic and cultivation practices, pest and disease control efforts, plant tissue culture protocols, and unexplored research areas involving this plant. Abstract Sweet potato is widely consumed in many countries around the world, including India, South Africa and China. Due to its valuable nutritional composition and highly beneficial bioactive compounds, sweet potato is considered a major tuber crop in India. Based on the volume of production, this plant ranks seventh in the world among all food crops. Sweet potato is considered a "Superfood" by the 'Centre for Science in the Public Interest' (CSPI), USA. This plant is mostly propagated through vegetative propagation using vine cuttings or tubers. However, this process is costly, labour-intensive, and comparatively slow. Conventional propagation methods are not able to supply sufficient disease-free planting materials to farmers to sustain steady tuber production. Therefore, there is an urgent need to use various biotechnological approaches, such as cell, tissue, and organ culture, for the large-scale production of healthy and disease-free planting material for commercial purposes throughout the year. In the last five decades, a number of tissue culture protocols have been developed for the production of in vitro plants through meristem culture, direct adventitious organogenesis, callus culture and somatic embryogenesis. Moreover, little research has been done on synthetic seed technology for the in vitro conservation and propagation of sweet potato. The current review comprehensively describes the biology, i.e., plant phenotypic description, vegetative growth, agronomy and cultivation, pests and diseases, varieties, and conventional methods of propagation, as well as biotechnological implementation, of this tuber crop. Furthermore, the explored and unexplored areas of research in sweet potato using biotechnological approaches have been reviewed.

Micropropagation of Hedychium coronarium J. Koenig through rhizome bud.

An optimized protocol was developed for in vitro plant regeneration of a medicinally important herb Hedychium coronarium J. Koenig using sprouted buds of rhizomes. The rhizomes with sprouted bud were inoculated on Murashige and Skoog (Physiol Plant 15:473-497, 1962) medium (MS) supplemented with either N(6)-benzyladenine (BA) alone (1.0-4.0 mg L(-1)) or in combination with 0.5 mg L(-1) naphthalene acetic acid (NAA). Of these combinations, MS supplemented with a combination of 2.0 mg L(-1) BA and 0.5 mg L(-1) NAA was most effective. In this medium, best shoots (3.6) and roots (4.0) regeneration was observed simultaneously with an average shoot and root length of 4.7 cm and 4.2 cm respectively. Regeneration of shoots and roots in the same medium at the same time (One step shoot and root regeneration) reduced the time for production of in vitro plantlets and eliminates the media cost of rooting. Cent-percent (100 %) success in plant establishment was observed in both gradual acclimatization process as well as when plants were directly transferred to outdoor in clay pots containing a mixture of garden soil and sand (2:1) without any sequential acclimatization stage.

Critical factors influencing in vitro propagation and modulation of important secondary metabolites in Withania somnifera (L.) dunal.

Withania somnifera (L.) Dunal is a valuable medicinal plant in the Solanaceae family. It is commonly known as Ashwagandha and is widely distributed around the globe. It has multiple pharmacological properties owing to the existence of diverse secondary metabolites viz., withanolide A, withanolide D, withaferin A, and withanone. It is in great demand in the herbal industry because of its extensive use. In this background, the major challenge lies in the rapid multiplication of elite cultivars of W. somnifera in order to produce genetically and phytoconstituents uniform plant material for pharmaceutical industries. Thus it is necessary to explore various biotechnological approaches for the clonal mass propagation and synthesis of pharmaceutically important constituents in W. somnifera. Though there are several studies on in vitro propagation on W. somnifera, yet many factors that critically influence the in vitro response and withanolides production need to be fine-tuned in the pretext of the existing knowledge. The current review focuses on the advancements and prospects in biotechnological interventions to meet the worldwide demands for W. somnifera and its bioactive compounds. This update on in vitro studies on W. somnifera will be useful to many researchers, entrepreneurs, and herbal industries looking for its in vitro mass multiplication and scientific utilization.