I think chance of getting somaclonal variations are more in callus regenerated plants than somatic embryos. If we go beyond 7-8 subcultures (through callus or shoot tip/axillary buds), the chances for getting variation is more. We have not observed any variations in somatic embryo regenerated plants in our lab.

Yes, somatic embryos have less genetic variability compared with the regenerants from calluses. Somaclonal variation depends upon the concentration of auxin particularly 2,4-D. If plants are not produced from a callus after 4-6 months, attempts should not be made to regenerate plants and new cultures should be initiated.

Please read this paper:

Singh, R. J., T. M. Klein, C. J. Mauvais, S. Knowlton, T. Hymowitz, and C. M. Kostow. 1998. Cytological characterization of the transgenic soybean. Theor. Appl. Genet. 96: 319 - 324.

Plants regenerated via somatic  embryogenesis (SE) tend to have less soma clonal variation than those obtained through organogenesis. Somatic embryos often arise from single cells and follow a strict developmental pattern comparable to zygotic embryogenesis which screens out mutations in genes governing embryogenesis. On the other hand, organogenesis involves multiple cells and defects in one cell could be compensated by other neighboring cells. Thus there is greater chance of defective cells getting included in the regenerated plant and thereby contribute to soma clonal variation.

I agree that chances of getting somaclonal varaiation is through callus regeneration or from isolated single protoplast culture.

Read: S.S.Bhojwani and M.K.Razdan. 1996. Plant Tissue Culture: Theory and Practice (2nd Revised Edition). Elsevier, Netherlands

or

M.K.Razdan. 2003. Introduction to Plant Tissue Culture, 2nd Edition. Science Publishers, Enfield USA. 

I think somatic embryogenesis leads to more somaclonal variation than organogenesis pathway.

At first, with due respect to my friends/ respected Sir, who give the previous answers, I want to say the statement "callus regenerated plants than somatic embryos" or "somatic embryos have less genetic variability compared with the regenerants from calluses" is not right. Because the somatic embryos may also induced from callus. So "either somatic embryo or callus derived plant" concept is not correct.

Secondly, though the somatic embryos are often arise from single cells where organogenesis involves multiple cells; so chance of somaclonal variation is greater in Somatic embryos. Because if the genetically variant cell can participate in somatic embryogenesis pathway then the product is obviously somaclonal variant, but if one cell is genetically variant among of the multiple cells which participate in organogenesis pathway then the product plants may not somaclonal variant. Because the genetically variant (or different from other normal cell) cell not produce the entire plants.

How can I study the uncertainty of propagation in the structural-acoustic systems? - ResearchGate. Available from: https://www.researchgate.net/post/How_can_I_study_the_uncertainty_of_propagation_in_the_structural-acoustic_systems [accessed Aug 18, 2015].

Dear Researchers,

Thank you very much for your helpful comments.

What are your opinions on direct organogenesis? How do you compare this pathway with somatic embryogenesis and indirect organogenesis?

Dear friend, direct organogenesis not comparable with  somatic embryogenesis pathway.  I mean direct pathway can compare with indirect pathway.

Organogenesis pathway may be direct or indirect. Similarly the somatic embryogenesis pathway is also either direct or indirect. 

The difference between direct & indirect pathway is in case of direct pathway the organ / somatic embryo can induce directly from the explant without any callus formation, whereas in case of indirect pathway the organ / somatic embryo can induce via callus formation.

Somatic embryogenesis mean formation of bipolar structure, whereas organogenesis means formation of unipolar (either shoot pole or root pole) structure.

somaclonal variations are more in organogenesis rather than somatic embryogenesis.

Somaclonal variations are more prevalent in organogenesis from callus tissue since callus cells are in an offactive state of cell divisions and more prone to chromosomal aberrations due to a no. of factors in the medium. Hence, the plants regenerated from such cells will be invariably polyploids or aneuploids

 I mean in an active state

Very interesting discussions. This is to Moquammel Haque. From your arguments one can see that indirect somatic embryogenesis could give rise to a good number of somaclonal variations as the cells from which embryos develop have already gone through callusing before embarking on embryogenesis pathway. Now, what should we expect as the difference  between direct organogenesis and direct somatic embryogenesis? And any publications on this?

Dear Haque,

Do you mean that we can't compare direct somatic embryogenesis with direct organogenesis? Can't we indicate what types of plantlets show more variations - plantlets from direct organogenesis or plantlets from direct embryogenesis?

Please attach reliable documents.

I have been working on rescuing F1 hybrid of Glycine max (soybean; 2n=40) x G. tomentella, 2n=78 for 25 years. I produced F1 plants with expected 2n=59. These plants were produced through the medium only 1ml\L BAP. I did not identify even amphidiploid. I had to use colchicine to double the chromosomes to produce amphidiploid (2n=118). I have not identified somaclonal variants. Thus, this is the end of further discussion. I have extensively covered this topic in my book on Plant Cytogenetics, second edition published by CRC Press..  

Dear Ali, the main source of somaclonal variation is "unorganized" callus, what always have a high ROS accumulation. That's why direct somatic embryogenesis have a very few probability for induction of somaclonal variation. Same is true for micropropagation. But as soon as you induce completely unorganized growth, the probability of somaclonal variation increasing dramatically. Best wishes!

Dear Researchers,

It is clear that the chance of variation via indirect regeneration (somatic embryogenesis or organogenesis) is higher than direct regeneration and I didn't ask it. I want to compare direct somatic embryogenesis, direct organogenesis and axillary shoot proliferation with each other and also indirect somatic embryogenesis with indirect organogenesis.

(Not direct with indirect regeneration................)

Regards

Fully concur with Ali. Both of us are interested only in comparisons of

1. Direct somatic embryogenesis  vs direct organogenesis or Axillary shoot proliferation?

2. Indirect somatic embryogenesis vs indrect organogenesis

Occurrence of scv depends on how many cycles of sub-culturing the callus has gone through before it develops SE or organogenesis.

It is Organogenesis which leads to more somaclonal variations than somatic embryogenesis

Organogenesis will lead more som. variation due to its multicellular nature, whereas som. embryos are mostly unicelluar in origin and  develop true-to type plants.

Please provide experimental adat and references

Does anyone know of publications where differences in the level of somaclonal variation of organogenesis and indirect somatic embryogenesis are reported, leaving aside ploidy and chimeras? It is important to take into account DNA methylation, histone modifications, and microRNA.

Another question, does anyone know if there are publications that report continuous clonal propagation through indirect organogenesis as we do with indirect somatic embryogenesis in callus or cell suspensions?