Plant hormones applied in in vitro cultures of Diospyros kaki

Diospyros kaki (Persimmon) was regenerated by direct organogenesis from in vitro grown leaf callus. A remarkable shoot multiplication rate of 25 was achieved within 18 weeks from 4 weeks old clumps applying trans-zeatin (2 mgl-1) and indole-3-butric acid (0.2 mgl-1). 

You plan to establish a mass propagation.

Which group of growth regulators (plant hormones) do the applied plant hormones in this report belong to?

IAA (indole-3-acetic acid) and IBA (indole-3-butyric acid) are naturally occurring plant hormones of the auxin- family. IAA is the most common and best known plant hormone among the auxins. Auxins play an important role in the coordination of many growth and behavioural processes in the plant. They contribute to organ shaping and are therefore fundamental for a proper development of the plant itself.

BAP (6-benzylaminopurine) is a synthetically produced cytokinin of the adenine-type. It stimulates cell division and influences the formation of blossom and fruit.

TDZ (thidiazuron) is a cytokinin of the phenylurea-type.

The plant growth regulator t-Zea (trans-Zeatin) also belongs to the family of cytokinins and occurs naturally.  It promotes growth of lateral buds and stimulates cell division to produce bushier plants.

http://en.wikipedia.org/wiki/Indole-3-acetic_acid

http://en.wikipedia.org/wiki/Indole-3-butyric_acid

http://en.wikipedia.org/wiki/6-Benzylaminopurine

http://en.wikipedia.org/wiki/Cytokinin

Why is there still a caveat about genetic authenticity of the clonal offspring?

Plants that have been produced by plant tissue cultures are normally identical clones of the mother plant. However, there is a phenomenon called somaclonal variation.

Somaclonal variation means all variation originating in cell and tissue cultures, where mistakes in the reading of genetic information happen frequently.

The main reasons for variations are chromosomal rearrangements, but the variations can be genotypic or phenotypic. In the latter case changes can be either genetic or epigenetic in origin. Typical genetic alterations are changes in chromosome numbers, chromosome structure and DNA sequence. Typical epigenetic related events are gene amplification and gene methylation.

Somaclonal variation is an important source of genetic variability. Yet for operations which require clonal uniformity it can be a great disadvantage, like in this case the rapid propagation of elite genotypes from Diospyros kaki.

Suggest how genetic authenticity is to be verified

There might be some morphological changes visible to the naked eye. If there are no changes visible, plant screening procedures can be applied to detect somaclonal variation.
There is a method called cytogenetic analysis. With this method chromosomal alteration and ploidy changes can be highlighted.  
The different molecular analytic techniques work with molecular markers to identify DNA sequences. 
  

https://en.wikipedia.org/wiki/Somaclonal_variation

http://cdn.intechopen.com/pdfs/40179/InTech-Somaclonal_variation_in_tissue_culture_a_case_study_with_olive.pdf

original article:
Sutter F. (2010), Diospyros kaki L. Plant regeneration via in vitro leaf derived callus