Somaclonal variation

Maddock, S.W. Semple, J.T. (1986). Field assessment of somaclonal variation in wheat. Journal of Experimental Botany, 37, 1114-28. 

Larkin, P.J. Skowcroft, W.R. (1981). Somaclonal variation - a novel source of variability from cell cultures for plant improvement. Theoretical and Applied Genetics, 60, 197-214. 

Somaclonal Variation and Secondary Product Synthesis. The induction and recovery of genetic variants by somaclonal variation technology can have a profound impact on the economic feasibility of secondary metabolite production. While most of the discussion up to this point has focused on cell culture production of secondary compounds, there are clearly a number of instances where whole plant production is both more efficient and economically prudent. This is especially true for those compounds... 

Figure 1. Somaclonal variation for development of high-producing cell lines.

Somaclonal variation in regenerated plants has been observed and reported since cell culture technology was very young (14). 

The original Larkin and Scowcroft paper also espoused the exploitation of somaclonal variation in crop improvement. It has been argued that using tissue culture to induce mutations is operationally and perhaps even mechanistically equivalent to mutagenesis via chemicals or ionizing radiation. A small number of papers have recently appeared, however, which demonstrate that the frequency and spectrum of mutants generated via mutagens vs. cell culture are indeed different (16). 

The application of somaclonal variation to crop improvement is attractive because it is cheap, simple and requires few assumptions as compared to more directed approaches (17). The glaring disadvantage of the phenomenon is that it is not qualitatively controllable. If one possesses a line which is genetically superior in all respect with one or few deficiencies, somaclonal variation can theoretically be induced to mitigate the deficiencies while... 

Increasing the solids content of tomato is a demonstration of the modification of multigenic traits by modern biotechnology. Although various institutions have utilized several approaches, only somaclonal variation has proven successful, with DNA Plant... 

To assist in enhancement of the commercial potential of high-solids variants, work on other important genetic traits is needed. Other somaclonal variations, (both... 

Genetic stability is provided by the fact that the moss is grown in small plant fragments and not as protoplasts or tissue cultures avoiding somaclonal variation. 

Improvement in taste or texture of vegetables and fruits, such as better tasting celery stalks and tomatoes with higher solids content (13). Somaclonal variations for selection of desirable variants, and somatic embryos (artificial seeds) have been especially useful in genetic engineering of improved vegetables. Several of these new crop varieties will be on the market within 2 to 4 years. 

Sowcroft WR, Larkin PJ. Somaclonal variation. CIBA F Symp 1998 137 21-6. 

In the production of somatic hybrids by chloroplast fusion, both nucleus and cytoplasm are combined. Moreover, the occurrence of somaclonal variation during culture and assortment of the cytoplasmic organelles can result in a wide range of hybrid types regarding their nuclear and cytoplasmic constitutions. 

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