Somaclonal Variation, Clonal Propagation, Micropropagation, Transient, Genetic, Polyploidy, Aneuploidy, Translocations, Inversions

Scholarships Dictionary Visa Details Study Abroad Exam Results Online Test Jobs

	Home
Tissue Culture, Micropropagation and Somaclonal Variation Tissue Culture, Micropropagation and Somaclonal Variation Introduction Cell and Organ Differentiation Cytodifferentiation Organgenic Differentiation Shoot bud Differentiation Somatic Embryogenesis Clonal Propagation or Micropropagation Bioreactors for Micropropagation and for bioactive Compounds List of Plant Materials,Which can be Propagated by Tissue Culture Synthetic Seeds for Micropropagation Production of Virus free Plants ELISA for Detection of Viruses Fungi Bacteria, MLOs, Mycotoxins and Hormones DAC-ELISA PAC-ELISA Maintenance of Male Sterile Parents for Hybrids through Micropropagation Micropropagation of Hybrid Plants Somaclonal Variation

Home >> Plant Biotechnology and Genomics >>Tissue Culture, Micropropagation and Somaclonal Variation >>Somaclonal Variation

	Somaclonal Variation For clonal propagation or micropropagation discussed above, shoot tips or axillary buds are used for direct propagation on culture medium without intervening callus phase. It has been shown in recent years, that regeneration from callus, leaf explants or plant protoplasts leads to the generation of considerable variation, described as ‘somaclonal variation’. This variation includes aneuploids, sterile plants and morphological variants, sometimes involving traits of economic importance in case of crop plants. This variation received increased attention and excitement during 1980s in view of its potential in crop improvement programmes. The usefulness of this variability in crop improvement programmes, was first demonstrated through the recovery of disease resistant plants in potato (resistance against late blight and early blight) and sugarcane (resistance against eyespot disease disease, Fiji disease, and downy mildew). In plants regenerated from callus, not only variability involving both nuclear and organellar DNA is observed, but variability even in chromosome number is observed in long-time cell cultures. This is exhibited in callus and in plants regenerated from the callus.
It may be necessary to remember that the above variation may be transient (epigenetic) or genetic; only the latter is transmitted to the next generation and is thus important for crop improvement of a sexually propagated crop. In several crops R₀, R₁ and R₂ progenies were subjected to genetic analyses and 3:1 segregation was observed, leading to the isolation of true breeding variants. Although the details of the genetic basis of somaclonal variation in most crops are still largely unknown, variation in structure and number of chromosomes has been suggested to be one possible basis. Polyploidy, aneuploidy, translocations, inversions and deletions have been reported in several cases. Meiotic crossing over involving symmetric and asymmetric recombination could also be responsible for a part of the variation observed in the regenerated plants. Methylation at the DNA level in tissue culture has also been considered as a possible reason for ‘somaclonal variation’.
Somaclonal variation has actually been used in plant breeding programmes. A number of plant species, where useful somaclonal variation. Different Steps Involved in Generation and Utilization of Somatic Variation Flow Chart

	Home
List of Some Crop Species where Desirable and Heritable Somaclonal Variation Overcoming Crossing Barriers Using Culture Technques Pre-Fertilization Crossing Barriers on Culture Techniques Post-Fertilization Crossing Barriers Embryo Rescue Embryo Culture Ovule Culture Ovary Culture Other Uses of Tissue Culture Endosperm Culture Nucellus Culture Germplasm Storage Examples of Storage of Plant Tissue Culture Status of Tissue Culture Technology in India Micropropagation Research in India Status of Tissue-Culture Technology in India-Semi Commercial Status of Tissue-Culture Technology in India Commercial Scale Production Somaclonal and Gametoclonal Work in India Secondary Metabolities Research in India

Language >> English | Français | Español | Deutsch | Italiano | Portugues | Japanese | Korean | Sim-Chinese