All human beings depend on agriculture that produces food of the appropriate quality at the required quantities. Food production, for both quantity and quality, in developed and developing countries around the globe, cannot rely solely on classical agriculture. During the last two decades, biotechnology have been adapted to agricultural practices and have opened vistas for plant utilization. Plant biotechnology has two important components, like tissue culture and molecular biology, which is changing the plant science in some areas.
The better insight into the control of plant regeneration, morphogenesis and control over patterns of cell division achieved is due to three major discoveries:
(1) the totipotency and regeneration ability of plant cells and tissues, as revealed by cell culture and micropropagation,
(2) production of secondary metabolites
(3) genetic engineering.
These have enabled both the control and biotechnological manipulation of vegetative growth, generative patterns and of micropropagation. Micropropagation is used routinely to generate a large number of high-quality clonal agricultural plants, including ornamental and vegetable species, and in some cases also plantation crops, fruits and vegetable species. Micropropagation has significant advantages over traditional clonal propagation techniques. These include the potential of combining rapid large-scale propagation of new genotypes, the use of small amount of original germplasm (particularly at the early breeding and/or transformation stage, when only a few plants are available), and the generation of pathogen-free propagates.
Micropropagation
Micropropagation begins with the selection of plant material to be propagated, clean stock material for propagation is important in the production of the healthiest plants. Often plants are first virus indexed to make sure they are clean and free of viruses. Once the plant material is chosen for culture, the collection of explant(s) begins and is dependent of the type of tissue to be used, and can include stem tips, anthers, petals, pollen and others. The explant material is then sterilized on their surfaces, usually in multiple courses of bleach and alcohol washes and finally rinsed in sterilized water. This small portion of plant tissue, which may be as small as a cell, is placed on a growth medium, typically containing sucrose as an energy source and one or more plant growth regulators (plant hormones).
Usually the medium is thickened with agar to create a gel which supports the explant during growth. Some plants are easy to grow on simple mediums but other plants need more complicated mediums before they will successively grow; some mediums include vitamins, minerals and amino acids. The medium is sterilized during preparation to prevent fungal and bacterial contaminations that can outgrow and smother the explant. Autoclaves and filter sterilization are used to remove potential contaminates; under smaller scales of production a pressure cooker is often used. The plant tissue should now begin to grow and differentiate into new tissues. For example, media containing cytokinins are used to create branched shoots from plant buds.
Multiplication
Multiplication is the taking of tissue samples produced during the first stage and increasing their number. Following the successful introduction and growth of plant tissue, the establishment stage is followed by multiplication. Through repeated cycles of this process, a single explant sample may be increased from one to hundreds or thousands of plants. Depending on the type of tissue grown, multiplication can involve different methods and mediums. If the plant material grown is callus tissue, it can be placed in a blender and cut into smaller pieces and recultured on the same type of culture medium to grow more callus tissue. If the tissue is grown as small plants called plantlets, hormones are often added that cause the plantlets to produce many small offshoots that can be removed and recultured.
Pretransplant
This stage involves treating the plantlets/shoots produced to encourage root growth and "hardening." It is performed in vitro, or in a sterile "test tube" environment. Root growth does not always occur in the earlier stages in plant cell culture, and is of course a requirement for successful plant growth after the micropropagation procedure. It is performed in vitro by transferring the plantlets to a growth medium containing auxin(s). "Hardening" refers to the preparation of the plants for a natural growth environment. Until this stage, the plantlets have been grown in "ideal" conditions, designed to encourage rapid growth. Due to lack of necessity, the plants are likely to be highly susceptible to disease and will be inefficient in their use of water and energy. Hardening typically involves slowly weaning the plantlets from a high-humidity, low light, warm environment to what would be considered a normal growth environment for the species in question. This stage (pretransplant) is not always performed, instead being incorporated into the last stage by encouraging root growth and hardening ex vitro, or in nonsterile plant media.
Objective
The main objective of this project work is
• To optimize the hormones BAP, FAP for multiplication of banana and to find out the suitable hormone for multiplication of banana.
• To optimize the rooting hormones like IAA, IBA, NAA and CHARCOAL.
• To compare the rooting hormones and to find out the best suitable hormone that enhances rooting in banana.
Method
Five different liquid medium culture methods for meristem propagation of bananas were investigated and compared with solid medium culture.
Treatments studied were: gelled culture medium (treatment 1); liquid medium with immersion of the plants (treatment 2); liquid medium with cellulose culture support (treatment 3); liquid medium with partial immersion of the plants (treatment 4); liquid medium aerated by bubbling (treatment 5); liquid medium with temporary immersion of the explants for 20 min every 2h (treatment 6). The highest multiplication rate (>5) was observed in explants subjected to temporary immersion in the mediu m.(D.Alvard et al.,1990) S.P.Anand and Jeyachandran.R.2004.have achieved high frequencies of multiple shoot regeneration from nodal explants on MS fortified with 5 mg/l BAP and 0.5 mg/l IAA in Musa spp.
The effects of indolebutyric acid (IBA) and α-naphthaleneacetic acid (NAA)] on in vitro propagation of banana (Musa spp. AAA) were of carbon sources (sucrose, glucose, fructose and mannitol) and auxins were studied .Of the carbon sources used ,sucrose induced highest frequency of shoot proliferation.Higher frequency of root induction was obtained in IBA and NAA combination (1:1; concentration of 2 mg dm−3) than at other concentrations of IBA or NAA alone.
Banana suckers were selected for micropropagation of banana. The suckers were collected from chembarambakkam. All the suckers were subjected to viral indexing before the sucker were selected for micropropagation. The explants were obtained from mother plants of grandnaine. The sucker was Immersed in Bavistin (Fungicide) over night at low concentration to avoid surface fungal contaminations. Bavistin was discarded and was rinsed well with sterile water.Tween 20 was added and washed for 20 mins to clean the surface of the sucker. After these treatments the explants was taken to Laminar Air Flow Chamber (LAF). Laminar air flow chamber was clean with 90 % alcohol before the micropropagation of banana. Forceps and blade holders with number 10 blades are steriled in steripot.The sucker was transferred in to clean sterile bottle and sterilized with 70% ethyl alcohol for 45 seconds. Then the suckers were treated with 0.12% mercuric chloride for 8, 10, 12, and 14 minutes.
Conclusion
Micro propogation technology can be used to mass propogate any kind of plants with genetically identical.In my studies I tried banana grande naine variety,the most cammon and wanted in agricultural business.Micropogation technology or plant tissue clture involves two different steps.One is initiation or sterilization of explants with mercuric chloride to get the clean cultures.The second step is media standardization to get different stages like multiplication,shooting and rooting.I concentrated in multiplication of banana. From my experiments I concluded 0.12%mercuric chloride for 12 min is the best concentration and timings for first sterilization.
Here it is obtained 70%succes rate. In second sterilization 0.1%for 5minutes is the best. Regarding multiplication of banana BAP 5mg/lit is the best among the other treatments.If we consider the cost BAP is cheaper than FAP.So BAP is the best hormone for multiplication of banana. In rooting hormone IAA could give 60% success and NAA could give 50%. Use of IBA gave only 20% of rooting.by using 2.0gm/l of charcoal 95% of rooting was observed in banana.Hence charcoal is considered as the best for rooting in banana..