Auxin effects on somaclonal variation and plant regeneration from mature embryo of barley (Hordeum vulgare L.)

Crop improvement through genetic engineering depends on effective and reproducible plant regeneration systems. In barley (Hordeum vulgare L.), immature embryos are the most commonly used as explant source for In vitro regeneration and genetic transformation but, mature embryos are alternative to immature embryo due to the fact that they have advantages such as easy storage and ready availability throughout the year. The effects of different concentrations (2, 4, 6, 8, 10 and 12 mg/l) of three auxins (2,4-D, dicamba and picloram) were evaluated in mature embryo culture of barley. Calli, embryogenic calli and regenerated plants were observed in all of the studied auxins. The MS (Murashige & Skoog basal medium) containing 12 mg/l dicamba was found to be the most effective for embryogenic callus, responded embryogenic callus and regeneration efficiency. Plant tissue culture can bring about genetic changes that are known as somaclonal variation. Genetic and epigenetic changes were examined by RAPD (Randomly Amplified Polymorphic DNA) and CREDRA (Coupled Restriction Enzyme Digestion-Random Amplification) techniques, respectively. Increased auxin concentration led to the decrease in the GTS (Genomic Template Stability) value. DNA hypermethylation occurred in higher concentrations of 2,4-D and picloram, while DNA hypomethylation was observed in dicamba.