leondumoulin.nl: 1: Somaclonal Variation in Crop Improvement I (Biotechnology in Agriculture and Forestry) (): Professor Dr. Y. P. S. Bajaj: Books.
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Thailand isolated improved varieties of banana and chrysanthemum using this technique Singh, Single cell callus cultures from F1 embryos rescued were initiated and induced to form plants showing somaclonal variation which were then selected for BYDV resistance. Cytological analysis of the genotypes showing stable resistance revealed that chromosomal rearrangement of the chromosome carrying Thinopyrum introgressed segment had occurred during the tissue culture phase to confer the stability Brettell et al.
The Biotechnology Centre at the Indian Agricultural Research Institute IARI has standardized the protocols of plant regeneration of Brassica carinata and is isolating somaclonal variants suitable for Indian conditions. Useful somaclonal variants for earliness, plant height, maturity, etc.
In vitro techniques for plants provide systems analogous to the prokaryotic systems where variants can be selected and mutations can efficiently be induced and isolated at cellular level.
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By applying effective selection pressure on naturally variant or mutagenically treated cell cultures viz. Using this technique, Chinese, Indian and Filipino scientists have isolated rice mutants tolerant to higher concentrations of salt. Mutants having higher protein and Iysine content in their seeds were also isolated.
Using this approach, pathogen-resistant mutants of tobacco, rice, wheat, barley, sugar cane and maize have been isolated and used in breeding programmes in several countries. In Japan, Nakajima, , disease-resistant lines of rice, tomato and tobacco were isolated using this approach Table 1. Table 1 Examples of disease-resistant plants successfully selected using tissue culture, Japan.
The technique is being used in several Asian countries, particularly in the case of orchids, peanuts, cotton, cabbages, citrus and peaches. In India, promising recombinants have been obtained using embryo rescue techniques in distant crosses of cultivated Phaseolus, jute and peanut. In China, using embryo rescue and in vitro culture of a distant hybrid Triticum aestivum x Agropyron elongatum, a new wheat variety, Xiaoyan No.
In Japan, three cultivars each of Citrus, Prunus, and Brassica species, and five cultivars of Lilium species were developed in recent years using the embryo rescue technique Ito, Japan and China are particularly deeply involved in this work. During the past ten years or so, as listed by Nakajima , Japanese scientists have reported successful protoplast culture in more than 70 plant species Table 2.
In China, plants regenerated from protoplast have been obtained in about 30 species, including vegetables, medicinal plants, legumes, and other economic crops as well as woody species such as poplar, elm and rubber trees. For the first time, Chinese scientists regenerated plants from monocot Polypogen fugax.
With recent reports of success on protoplast culture and regeneration of wheat, it is now possible to have protoclones of most of the major food crops.
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However, in several cases, the regeneration frequency is low and should be improved. The Republic of Korea had produced cybrid lines of mushrooms which outyielded the best parents and checks by about percent. Successful regeneration of plants from cell fusion are reported from about 50 interspecific and intergeneric protoplast combinations in the region.
Half of these are known from Japan Table 3. Using cell fusion techniques, scientists have developed novel citrus hybrid varieties, such as "Oretachi" orange plus trifoliate orange , "Shuvel" Satsuma mandarin plus navel orange , "Gravel" grapefruit plus navel orange , "Murrel" murcott plus navel orange and "Yuvel" Yuzu plus navel orange. Using asymmetric cell fusion techniques, Japanese scientists developed Ms-F , the first commercial tobacco male sterile line developed in the world bred by cell fusion.
Such asymmetric male sterile lines for commercial exploitation of F, hybrids have been also bred in carrots, cabbages and eggplants Nakajima, In China, somatic hybrids between Nicotiana tabacum and N. Chinese scientists have also pioneered the pollen tube gene introduction technique for cotton and rice breeding. In this technique, after self-pollination, the desired exogenous DNA is introduced to the embryonic cells. Seeds which develop from such transformed embryos result into transformed plants, thus avoiding the need for protoplast fusion technique.
Genes responsible for disease resistance and other traits have been transformed successfully in rice and cotton.
But this technique has low repeatability. In fact, the entire cell fusion technique has not been as successful in producing somatic hybrids as initially expected. With the availability of Agrobacterium-mediated and biolistics-based methods of gene transfer, the thrust on the protoplast fusion approach has somewhat slackened, although the asymmetric fusion method has special appeal for production and diversification of cytoplasmic male sterility and manipulation of other cytoplasmically controlled systems.
Cultured plant cells retain their metabolic potential and can be used efficiently for producing useful secondary metabolites of commerce such as pharmaceuticals, dyes, food additives, sweeteners, flavours and taste enhancers, essential oils and aromatic products. Herbal medicines are popular in China, India and other Asian countries and are gaining importance in the West.
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Chinese scientists have been using tissue culture since the late s for the production of ginseng sapanins from Panax ginseng. Diasgenin, a female contraceptive produced from in vitro cultured Dioscorea spp and a male contraceptive based on gossypol from tissue-cultured Gossypium spp are under extensive trials in China. In addition, tissue culture technique has been successfully used in the cultivation of Scopolia acutangula, Artemisia annua, and Rauwolfia yunnanesis.
India is also using this technique for production of diasgenin and other medicinal and aromatic products. Cell cultures can also be used as factories for bioconversion of intermediate compounds into more valuable products. Shikonin, an expensive compound obtained from the roots of Lithospermum erythrorhizon, has been used by the Japanese traditionally as a vegetable dye and in cosmetics and toiletries.
However, due to overexploitation and other human activities, the plant has become almost extinct in Japan. To reduce their dependence on the import of this plant material, Japanese scientists have developed a tissue culture method for the commercial production of shikonin. Another example where tissue culture production of an industrial compound has reached commercial level is berberine from Coptis juponica Fujita, In tissue cultures the yield of high value compounds can be enhanced by feeding the cells with the intermediate compounds of their biosynthetic pathways biotransformation , manipulation of culture conditions and selecting high yielding cell lines.
With further refinements of techniques the bioreactor and fermenter based production of secondary metabolites could be rendered highly cost-effective and time-saving. Several plant species in the region, including a few commercial species, produce recalcitrant seeds and it is thus difficult to conserve them through seeds. Furthermore, some species are shy seed bearers and even fail to produce seeds. In addition, living collections of clonally propagated perennial crops face the problems of maintenance of heterozygous and heterogeneous populations, the long life cycle and large space required, and a high possibility of exposure to the threats of pests and diseases and other biotic and abiotic stresses.
To circumvent these difficulties, in vitro conservation of vegetatively propagated and recalcitrant seed-producing species is being increasingly adopted as a complement to other methods of conservation. For short- to mediumterm storage working and active collections , the slow growth method is used whereas for long-term storage base collections cryopreservation is the method adopted. There is therefore a good case in the region for in vitro storage of several of the important plant species, and the countries involved are in fact building such facilities.
Orchid germplasm is routinely maintained in vitro in India, the Philippines and Thailand. With assistance from the Department of Biotechnology, the National Bureau of Plant Genetic Resources NBPGR , in India has established extensive in vitro storage facilities and is already storing germplasm collections of certain root and tuber crop species as well as a few fruit species. The bulk of the Indian potato collections at Central Potato Research Institute, Shimla, are conserved through tissue culture.
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China is also developing comprehensive facilities for in vitro conservation. The Southeast Asian Banana Germplasm Bank, currently maintained as a living collection in Davao, the Philippines, has already been put under in vitro storage. The country is also maintaining some of its desired soft coconut germplasm through embryo culture.
Malaysia is in the process of duplicating some of its ex situ living collections of oil palm and rubber as in vitro collections.
Several of the Pacific Island countries are maintaining their taro collections in vitro because of the danger of the accessions being lost to viral and other diseases under field conditions. Thus, there is wide scope for using biotechnology for conservation and utilization of tropical plant germplasm Sastrapradja and Sastrapradja, ; Withers, ; Singh, Besides the developed countries, several developing Asian countries are using monoclonal antibody techniques for identification of pathogens and for indexing materials.
In China, more than 50 kinds of hybridoma strains have been constructed which secreted various kinds of monoclonal antibodies to viruses, bacteria, cancer, etc.
Somaclonal Variation in Crop Improvement II in SearchWorks catalog
India is applying monoclonal antibody techniques for the diagnosis and epidemiology of tungro virus of rice and other important viruses. Several other developing countries have also been using this technique coupled with ELISA tests to detect peanut viruses. Volume 10 Issue 1 Jan Volume 9 Issue 12 Dec , pp. Volume 8 Issue 12 Dec , pp. Volume 7 Issue 6 Dec , pp. Volume 6 Issue 6 Dec , pp. Volume 5 Issue 6 Dec , pp.
Volume 4 Issue 4 Dec , pp. Volume 3 Issue 4 Dec , pp. Volume 2 Issue 4 Dec , pp. Volume 1 Issue 4 Dec , pp. Nirrala Production of hairy root cultures of lettuce Lactuca sativa L. Tissue culture and genetic analysis of somaclonal variations of Solanum melongena L. De Gruyter Online Google Scholar. Abstract The present study was designed to analyze genetically somaclonal variants using biochemical and molecular markers. By using the comment function on degruyter. A respectful treatment of one another is important to us.