Ginger (Zingiber officinale Roscoe)

Medicinal plants have long been used in the treatment of several diseases throughout the world. Ginger (Zingiber officinale Roscoe), a herbaceous perennial plant from the Zingiberaceae family, is one of those plants. There are 24 genera and 300 species under this family; the genus Zingiber has about 20 species as well (Newman, 2001). It is found in tropical and subtropical regions that bear flowers. It used as a spice, food, flavouring agent, and medicine.

In 2019, the global production of ginger was 4.08 million tons, which demonstrates its significant economic value in world trade (Li et al. 2021). It cannot be sexually propagated due to poor flowering and ginger is an unfertile species that failed to set seed (Kambaska & Santilata, 2009). Therefore, ginger plant possesses perennial tuberous or rhizomatous that are used for its vegetative propagation (Nair, 2019). The plant generates an upright, annual stalk (pseudo-stem), 60 to 90 cm tall, with dark green leaves. Its stalks are covered with flat sheaths that may be taken off stalk; 8 – 12 distiches leaves are present on the stem. The leaves are with long blades, or flat and stalk less blades; are alternative (alternate), lance late, linear lance late, specula, 10 to 21 cm tall and 2 to 2.5 cm wide.

The presence of a high polyphenols and flavonoids content in its leaves, stem, and rhizome has been defined as the critical factor for its pharmacological effects (Ghasemzadeh et al., 2010). These polyphenols and flavonoids compounds are natural sources of antioxidants (Haida et al., 2019). As rhizome is an economically exploited part of the plant, using a high proportion of ginger rhizomes as starting material for cultivating the plant in the next growing season negatively affects its supply in the market. It has been used as spice and medicine for treating cancer (Zhang et al., 2021); cardiovascular disease (Ghafoor et al., 2020); diabetes (Said et al., 2020); and several other illnesses such as cold, nausea, asthma, and cough (Choi et al., 2018). Owing to the global pandemic of COVID-19, ginger consumption gained more interest. It helped alleviate the severe symptoms of COVID-19 positive patients and reduced the recovery time in those patients (Rangnekar et al., 2020).

The success of in vitro technique largely depends on the aseptic culture establishment, shoot regeneration capacity, rooting, and acclimatization. Rhizome buds, which are often used as the source of explants in Zingiberaceae, have been proven to be more responsive. However, the initial establishment of contamination-free culture is difficult owing to the exposure of rhizomes to various soil pathogens (Meenu & Kaushal, 2017; Thakur et al., 2018). These pathogens need to be eliminated by surface sterilization of the explants. Vegetative propagation of ginger has a high risk of spreading infections. Slow propagation rate and the risk of disease transmission by sectioning of the rhizomes have deprived propagation by conventional means. Therefore, plant tissue culture is considered the best alternatives method that may supply a large number of planting materials (Hamirah et al., 2010).