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Ginger (Zingiber officinale Rosc, Family- Zingiberaceae): A Natural Gold (Gosh, 2011) has an ancient history. It is possible that as long as 5,000 years ago, spice caravans were carrying dried Ginger from India to the Middle East. It is one of the best known of spices and it is believed that its medicinal properties have been known in China for thousands of years. Indeed, the plant was mentioned in Emperor Shen Hung's Pen Tsao Ching (The Classic Book of Herbs), which he wrote in 3000 BC. Although frequently associated with Traditional Chinese medicine, Ginger has an ancient reputation in India and is specifically mentioned in the Ayurveda, the Hindu manual of medicine written in the fifth century B.C. The ancient Romans also valued Ginger for its' culinary and medicinal uses. Largus, a physician in the Roman army and the author of a book entitled, “De Compositione Medicamentorum” described the Roman military expedition to Britain and was responsible for the introduction of Opium and Ginger to the island. Another Roman, Pedianos Dioscorides, wrote about Ginger in his famous, “De Materia Medica” (77BC). Subsequently, Ginger received a mention in the Islamic holy book, the Koran where it says that among the righteous in Paradise are passed vessels of silver and goblets of glass and a cup, the admixture of which is Ginger. Later, when the spice came to medieval Europe, Queen Elizabeth-I used it as a digestive aid. The Chinese records showed ginger was cultivated in the Malacca region (Malaysia) in 1416. During the 15th century, Spanish explorer called Francisco de Mendosa transplanted the Ginger plant that by 1547 and brought it back to Spain from the East Indies. Thereafter, following the arrival of Spanish explorers and settlers to the North American continent, Ginger was soon introduced and became naturalised there.
Ginger, one of the most valued horticultural crops of the world, is used extensively as spice and for its medicinal properties. Estimated world trade of ginger is US$ 2900 million. India is the largest producer of ginger in the world (0.38 million tons in 2009) cultivated about 1.06 lakh hectares. The ginger rhizome contains various biologically active compounds such as gingerol, shogaol, ginger protease, capsaicin and several sesquiterpenes like zingiberol, zingiberenol (Tang and Eisenbrand, 1992). The species is distributed in tropical and subtropical Asia, Far East Asia and Africa (Wahyuni et al., 2003). Although the origin is unknown, the species probably originated in tropical Asia and China (Purseglove et al., 1981) where it is under cultivation for centuries (Ravindran et al., 2005). In India, most of the popular commercial varieties are clonal selections from traditional cultivars. The crop improvement programmes of this species are confined to evaluation and selection of naturally occurring clonal variations (Rout et al., 1998; Palai and Rout, 2007). Samples are unable to select from diverse agro-ecological conditions due to low genetic diversity in ginger (Ravindran et al., 2005).
Ginger belongs to Family: Zingiberaceae (Hooker, JD., 1894) is a herbaceous, perennial, the rhizomes of which are used as an important spice and medicine. The botanical name for Ginger - Zingiber officinale - was given by the Swedish botanist C. Linnaeus. It comes from the Sanskrit word of singabera, which means 'shaped like a horn.' The term officinale simply means that the plant is commonly available and is useful to humans in medicine and as a food. The Family contains about 1400(aprox.) species in 50 genera, along with four other families is placed in the order Zingiberales which belong to class Monocotyledones. It is one grown as an annual herb for its spicy underground rhizomes. Rhizomes give rise to branched roots. The pseudostems reach a height of 50–120 cm. It has dark, erect stems with simple, lanceolate, and smooth leaves are alternate and about 25 cm long. The thick, fibrous buff to white tuberous rhizome is perennial and has a spicy, warming smell and a pungent, citrus like taste. It blooms have a small green inflorescence with white and maroon flowers. Ginger is asexually propagated from the rhizome. The flowers of ginger are usually sterile and rarely set seed.
Members of the family have distributions in the tropics of south and south-eastern Asia specially Indomalaysia and cultivated throughout the tropical and sub-tropical region, was among the first vegetative cultivated plants. The plant is a native of Asia, but is grown throughout the tropics and wherever there is a rich soil and a warm climate. There are, however, many naturally occurring varieties of Zingiber officinale, approximately 500 in India alone. Ginger is cultivated in most of the states in India. However, states namely Kerala, Meghalaya, Arunachal Pradesh, Mizoram, Sikkim, Nagaland and Orissa together contribute 70 per cent to the country’s total production. Ginger grows well in warm and humid climate and is cultivated to an altitude of 1500-3500 meter above sea level. Ginger can be grown both under rain fed and irrigated conditions. For successful cultivation of the crop, a moderate rainfall at sowing time till the rhizomes sprout, fairly heavy and well distributed showers during the growing period and dry weather for about a month before harvesting are necessary. Ginger thrives best in well drained soils like sandy loam, clay loam, red loam or lateritic loam. A friable loam rich in humus is ideal. However, being an exhausting crop it is not desirable to grow ginger in the same soil. Differing growing conditions and cultivation techniques result in each variety having its' own unique aroma and flavour.
An ancient remedy, Ginger is used for many purposes. As a stimulant, it helps to improve peripheral circulation. In fevers, it promotes perspiration. It is also excellent for treating dyspepsia, colic and flatulence. Externally, it forms the base for various muscle strains and fibrosistis treatments. It is also used in medicines, particularly in traditional medicines of India (Lawrence 1984; Selvan et al., 2002). Ginger is an important commercial crop in tropical and subtropical countries. The rhizome, or modified underground stem of ginger, is used worldwide as a spice for flavouring a multitude of foods and food-products. India is the largest producer and exporter of ginger in the world, followed by China, Nigeria, Indonesia, Bangladesh and Thailand. In India, Kerala State ranks first in terms of area planted and total production (Selvan et al. 2002). The underground rhizomes are the medicinally and culinary useful part of the plant.
The chemistry of ginger is well documented with the respect to the oleoresin and volatile oil. More than 400 chemicals have been identified in ginger rhizome. Geography, age of rhizome at harvest and extraction methods determines the relative proportions of chemicals. Chemical constituents of ginger classified to volatile oils which constitutes (1-3%) mainly of zingeberene nonvolatile pungent compounds oleo-resin constitute (4-7.5%) mainly gingerols and other constituents with more than 50% of starch, many fats, waxes, carbohydrates, vitamins and minerals. A difference in the type and level of major chemical constituents was detected among ginger rhizomes collected from different plantation regions.
Rhizome rot is a serious disease of ginger causing considerable economic loss to growers in different countries. To ensure effective and sustainable disease management, early detection and authentic identification of pathogen are considered as prerequisites. On the contrary, exploitation of host defense is one of the most reliable non-conventional strategies of plant disease management. The main pathogens associated with this disease are the fungi like Pythium sp., and Fusarium spp., along with the bacterium Pseudomonas spp and the root knot nematode sp. Meloidogyne have been isolated from diseased rhizomes .Plants from infected rhizomes are stunted and yellow, lower leaves dry out and turn brown then eventually all aboveground shoots dry out completely. Plant collapse is very slow (up to several weeks). Diseased rhizomes show a brown discolouration, are normally shriveled in appearance and eventually decay leaving the outer shell intact with only fibrous internal tissue remaining. The disease is spread unintentionally by the use of infected seed pieces from the previous crop, although these may appear normal and healthy. Hence, selecting clean material based on appearance may not be sufficient to control the disease.
Rhizome rot of ginger caused by Pythium aphanidermatum (Edson) Fitz is a major constraint for the production of healthy rhizome, sometimes causing total failure of crop (Fagaria et al. 2006). Chemical control of this pathogen is not economical because of high cost of chemicals; break down of resistance, environmental pollution, deleterious effect to non target beneficial soil micro-organism and ultimately the choice of the consumer for a organic product. Rhizome rot or soft rot is a highly destructive disease in ginger; in some areas of the world, soft rot is known to destroy 80 to 90% of the annual crop (Lawrence, 1984; Dake, 1995). Many species of the oomycete pathogen Pythium have been associated with soft rot, but, of them, the most prevalent and widely distributed species is P. aphanidermatum (Dake and Edison, 1989). This oomycete pathogen is soil borne. Infection begins at the collar region of the pseudostem and spreads into the rhizome, and can cause complete decay of the inner tissues. Associated foliar symptoms appear initially as yellowing of lower leaves, which gradually spreads to all leaves of the plant, followed by wilting and complete desiccation (Selvan et al., 2002).
Pythium soft rot of ginger is notoriously difficult to manage (Kamoun et al. 1999). Chemical treatment of seed rhizome (Lawrence 1984; Selvan et al. 2002) and the application of bio-control agents (Selvan et al., 2002)15 have been used to control soft rot. However, genetic improvement, the most desirable method of disease management, has been so far limited in ginger for two reasons. First, all ginger cultivars available today are highly susceptible to soft rot and no resistance or tolerance source has yet been identified (Dake, 1995). Second, since ginger is an obligatory asexual species (Hooker, 1894), propagated exclusively through its rhizomes, gene introgression through sexual crossing is impossible. Consequently, no effort has been made to systematically evaluate the wild relatives of ginger for soft rot resistance.
Recent progress in somatic hybridization (Fock et al., 2000; Collonnier et al., 2003; Tek et al., 2004) functional genomics (Yamazaki and Saito, 2002) and transgenic approaches (Punja, 2001; Song et al., 2003) suggests the possibility of broadening the genetic base of ginger through these non-traditional molecular approaches. In this study, we evaluated a selected set of species belonging to the family Zingiberaceae in order to locate a suitable donor for soft rot resistance. In this study molecular characterization is done on rhizomes of ginger using is enzymes such as Esterase, Acid phosphatase, Peroxidase and Polyphenolic oxidase are being multiple forms of enzymes and proteins are primary gene products. Variation in their structure should give reliable information about the variability in their genome as they are less susceptible to environmental influence than the secondary products of metabolism which are formed as a result of enzyme activity. Isoenzymes are theoretically well suited to identify closely related individuals or clones, simply by comparison of phenotypic banding patterns. Besides isoenzymes total soluble protein and DNA markers are evaluated.
RAPD (Random Amplified Polymorphic DNA) is the most advantageous in order to amplify the DNA since the DNA sequence is not known. RAPD does not require any specific knowledge of the DNA sequence of the target organism. The identical decamer primers will or will not amplify a segment of DNA, depending on positions that are complementary to the primers' sequence. For example, no fragment is produced if primers annealed too far apart or 3' ends of the primers are not facing each other. Therefore, if a mutation has occurred in the template DNA at the site that was previously complementary to the primer, a PCR product will not be produced, resulting in a different pattern of amplified DNA segments on the gel.
Soft rot is the most destructive which results in total loss of affected clumps. The disease is soil-borne and is caused by Pythium aphanidermatum, P. vexans and P. myriotylum are also reported to be associated with the disease. The fungus multiplies with buildup of soil moisture with the onset of south west monsoon. Younger sprouts are the most susceptible to the pathogen. The infection starts at the collar region of the pseudo stem and progresses upwards as well as downwards. The collar region of the affected pseudostem becomes water soaked and the rotting spreads to the rhizome resulting in soft rot. At a later stage root infection is also noticed. Foliar symptoms appear as light yellowing of the tips of lower leaves which gradually spreads to the leaf blades. In early stages of the disease, the middle portion of the leaves remain green while the margins become yellow. The yellowing spreads to all leaves of the plant from the lower region upwards and is followed by drooping, withering and drying of pseudostems.
Several spp. of Pythium have been reported as causal agents of soft rot in different parts of the world. Six species were recorded in different parts of India (excluding synonymous taxa). Among these, P. aphanidermatum and P. myriotylum are widely distributed, whereas the other species are restricted to certain pockets. Colonies of P. aphanidermatum on corn meal agar with cottony aerial mycelium, on potato-carrot agar with some loose aerial mycelium without a special pattern. Main hyphae up to 10 μm wide. Sporangia consisting of terminal complexes of swollen hyphal branches of varying length and upto 20μm wide. Oogonia terminal, globose, smooth, 20-25μm diameter. Antheridia mostly intercalary, sometimes, broadly sac shaped 10-14μm long and 10-14μm wide, 2 per oogonium, monoclinous or diclinous, oospores aplerotic (18-22μm) diameter, wall 1-2 μm thick. Colonies of P. ultimum on corn meal agar forming cottony aerial mycelium, on potato carrot agar with radiate pattern. Main hyphae up to 11μm wide, sporangia mostly not formed and zoospores very rarely produced through short discharge tubes at 50C. Hyphal swellings globose, intercalary sometimes terminal 20-25μm diameter. Oogonia terminal, sometimes intercalary, globose, smooth walled, 20-24μm diameter, antheridia either one per oogonium, sac like, mostly monoclinous originating from immediately below the oogonium, sometimes hypogynous, or 2-3 and then either monoclinous or diclinous and frequently straight. Oospores are single, globose 12-21 μm diameter and wall often >2μm thick.
Treatment of seed rhizomes with mancozeb 0.3% for 30 minutes before storage and once again before planting reduces the incidence of the disease. Cultural practices such as selection of well drained soils for planting is important for managing the disease, since stagnation of water predisposes the plant to infection. Seed rhizomes are to be selected from disease free gardens, as the disease is also seed borne. Application of Trichoderma harzianum along with neem cake at 1 kg/bed helps in preventing the disease. Once the disease is located in the field, removal of affected clumps and drenching the affected and surrounding beds with mancozeb 0.3% checks the spread of the disease.
Present study on, “Integrated Management of Rhizome rot of Ginger in Orissa” have under taken due to less knowledge in case studies in Orissan agro-climatic zones of Ginger cultivation. There is not any available information or work on soft-rot resistant varieties among cultivars of Zingiber officinale available in Orissa condition. Many reports are there huge loss of crop in field condition and also in storage by which Orissa face economic and qualitative loss. Our aim is selection of resistant variety detecting from both field and laboratory screening. We use advance technology for selection of resistant cultivars through biochemical marker and molecular marker analysis. Besides selection of resistant cultivars, we also emphasize on the cultural practice, use of chemical fertilizer and pesticides, use of available biological control and integrated approach to control the rhizome rot disease in Orissa. To achieve the goal of the present study the following objectives and plan of work have been undertaken.
- To find out pathogens involved different locations and isolation of pathogens proving the pathogenicity.
- To find out a suitable variety with high yield and minimum disease.
- Improvement of biopesticide for disease control.
- Management of disease through integrated biological and chemical methods
- Detection of suitable biochemical and Molecular markers for future breeding programmes to get disease resistant varieties.
- Selection of resistant varieties through biotechnological approach.
(1) Survey of disease at different locations, collection of germplasms and evaluation rhizome rot.
(2)Identification of suitable germplasm on disease resistant.
(3) Estimation of Yield loss due to disease.
(4)Screening through biotechnological approach.
(5) Detection of main pathogen, isolation in Orissa condition.
(6) Phytopathological test through Koch’s postulate.
(7)Biotechnological methods for varietal evaluation-I :Protein content, fibre content, phenol content, Enzymes involved in susceptible and resistant varieties (Polyphenol oxidase,Peroxidase,Esterase etc ).
(8)Biotechnological Method-II: a) Study of Isoenzyme pattern of different varieties. b) Molecular characterization (DNA profiling)
(9) Cultural management by dosages of host nutrient, and plant spacing.
(10) Impact of Biological pesticide, chemical pesticide and integrated approach.