1.1 Introduction
Ginger (Zingiber officinale Rosc) is a monocotyledonous, herbaceous, tropical plant belonging to the family Zingiberaceae. It’s a perennial plant usually grown as an annual crop. The crop is native to southern Asia mainly in India and china from where it spread to most tropical and subtropical countries. The plant is erect, has many fibrous roots, aerial shoots (pseudo stem) with leaves, and the underground stem (rhizome) where the ginger spice is obtained (Vasala, 2012). The roots of ginger are of two types, fibrous and fleshy. After planting, many roots having indefinite growth grow out of the base of the sprouts. These are the fibrous roots, and the number of such roots keeps on increasing with the growth of tillers. These fibrous roots are thin, have root hairs (Ravindran and Babu, 2016).
As a prelude to other parts of this study, this chapter will discuss the background upon which this study was initiated, the statement of problems that led to this study, the Aim and Objectives of the study. Others are Significance of the study, Scope of work, Research questions, Limitations of the Study and Definition of technical terms.
1.2 Background of Study
Ginger (Zingiber officinale Rosc) is a perennial herb that grows from underground rhizomes. The rhizomes are often mistakenly called the “roots”. Botanically, it is the rhizome that is characterised with the slightly hot, citrus-like taste and aroma. Ginger belongs to the family, Zingiberaceae. Members of the family are mostly advance monocotyledonous plants and are rhizomatous herbs. They are found throughout the tropical and subtropical regions but are mainly distributed in Asia. Ginger is the tenth most important spice in the world (McGee, 2004). Ginger rhizomes are used in pharmaceutical industries. It is rich in secondary metabolites such as oleoresin (Bhagyalakshmi and Singh, 1988). The demand for fresh and dry ginger and its essential oil in the world market is high. Ginger is propagated vegetatively using underground rhizomes. Most farmers use planting materials saved from previous harvest. These materials could have been sold for cash. Contingent on this, many farmers are reluctant to use healthy succulent rhizomes for planting. These are rather sold thereby resulting in shortage of planting materials.
Tissue culture technique can be applied to mass-produce seedlings for distribution to ginger farmers. This however, is not cost effective now due to lack of the necessary materials required for tissue culture. Most of the materials for tissue culture are not locally available and are therefore procured at high amount. One of such materials is the gelling agent, agar. Agar represents one of the most expensive tissue culture media components. It is widely used for preparing solid and semisolid plant tissue culture media because it withstands temperatures of about 1000C without being denatured (Scholten and Pierik, 1998). Therefore, establishment of plant micro propagation laboratories must be based on cost effectiveness. Gelatin that is cheaper when used at a concentration of 100g/1 is currently not widely used because it denatures at 250C. Methocel (methyl cellulose) an alginate is also cheaper than Agar. However, Adaoha and Roscoe (1982) observed that there are two disadvantages associated with the use of alginates. The first is that solutions cannot be autoclaved without alginate breakdown during sterilization at high temperatures. The second disadvantage is that, alginate reacts with divalent metal cations (Be2+, Mg2+, Zn2+, Cd2+, Hg2+ and Pb2+) which may cause nutrient deprivation.
Ginger has no information on the primary centers of domestication since ginger rhizomes can be easily transported over long distances and spread all over the tropics and subtropics hence the most dominantly grown spice as discussed by Ravindran and Babu (2016). Dinesh (2017) stated that ginger is one of the earliest known oriental spice. Ginger was introduced in East Africa by the Arabs in the thirteenth century (Okwuowulu, 2016).
Therefore, in Nigeria where the research was carried out, the activities that was conducted is to know the Effect of Different Concentrations of IAA (Plant Hormone) on Root Initiation.
1.3 Statement of Problems
Investigation revealed that ginger producers lack appropriate skills, knowledge and information on ginger plant hormone (Geta and Kifle, 2011). The producers are not aware of market information like value chain information including price at the end markets, demand situation and quality of the products. These compel them to sell at relatively low price. The determinants of this profit are also not known well. This is partly due to limited research on horticultural crops. Lack of such knowledge makes it uncertain to the traders as to what prices to charge, and at what frequency to trade. If this uncertainty is not urgently addressed, many traders will be driven out of retail ginger trade, to the detriment of Nigeria’s economy.
1.4 Aim and Objectives of Study
The aim of the study is to investigate the Effect of Different Concentrations of IAA (Plant Hormone) on Root Initiation. In achieving this aim, the following specific objectives were laid out as follows:
- To investigate the effect of different concentrations of plant hormone on root initiation.
- To determine the best pre-initiation treatment for in-vitro ginger multiplication.
- To compare agar gelled medium with cassava gelled medium in in-vitro propagation of ginger at the initiation stage.
- To determine the effect of plant growth hormones – auxin and cytokinin on in-vitro propagation of ginger using agar as a gelling agent.
1.5 Research Questions
The study came up with research questions so as to be able to ascertain the above stated objectives. The specific research questions for the study are stated below as follows:
- What is the effect of different concentrations of plant hormone on root initiation?
- What is the best pre-initiation treatment for in-vitro ginger multiplication?
- What is the effect of plant growth hormones – auxin and cytokinin on in-vitro propagation of ginger using agar as a gelling agent?
- What is the linkage between agar gelled medium with cassava gelled medium in in-vitro propagation of ginger at the initiation stage?
1.6 Significance of Study
This study will be of immense benefit to plant scientist and other researchers who intend to know more on this study and can also be used by non-researchers to build more on their research work. This study contributes to knowledge and could serve as a guide for other study.
1.7 Scope of Study
The scope of the research is focused on the Effect of Different Concentrations of IAA (Plant Hormone) on Root Initiation in Nigeria.
1.8 Limitations of the Study
During the course of this study, many things militated against its completion, some of which are:
- Time Constraint: The time frame given to accomplish this project was very short due to school academic calendar and it was carried out under pressure which made the researcher not to implement some necessary features.
- Research material: availability of research material is a major setback to the scope of the study.
- Frequent power failure: This made the researcher append more money on fuel to ensure sustainable power.
- Financial Constraint: Insufficient fund tends to impede the efficiency of the researcher in sourcing for the relevant materials, literature or information and in the process of data collection (internet).
1.9 Definition of Terms
Ginger: Ginger is a flowering plant whose rhizome, ginger root or ginger, is widely used as a spice and a folk medicine.
