RAPD Analysis of UV-B-Induced Variations in Somaclones of Vernonia cinerea

Plantlets were regenerated through callus-mediated organogenesis after UV–B irradiation (280–320 nm, 0.863–5.28 kJ m) in Vernonia cinerea and were analyzed by Random Amplified Polymorphic DNA with 10 random decamers to assess UV–B induced polymorphism. A total of 45 different somaclones were selected based on difference in morphology compared to the parent plant. Out of the 10 primers chosen for initial screening of polymorphism in these 45 somaclones and one parent plant (total 46 genotypes), 8 primers gave amplified polymorphic products. A total of 1347 scorable bands were generated. The value of PIC (polymorphic information content) for each primer ranged from 0.238 to 0.361 with an average of 0.285. Pair-wise genetic similarity coefficients generated from all possible genotypes ranged from 0.3929 to 0.9667. All the calliclones exhibited up to a mean of 77.5% variation from the parent genotype except somaclone 14 that showed 97% similarity. As indicated by the genetic similarity indices, UV-B irradiation is a good way for generation of high frequency morphological and genetic variants during callus mediated shoot regeneration in V. cinerea and can be used for selection towards desirable traits, such as salt or drought stress. _____________________________________________________________________________________________________________