comparison of comet assay parameter patterns between self-pollinated and cross-pollinated diploid medicago species, their resulting tetraploids and cultivated cultivars

Three parameters of comet assay (tail length, tail intensity, and tail moment) were used to compare the autotetraploids produced from three populations of cross pollinated medicago sativa spp. caerulea  and five diploid self-pollinated species from medicago genus. these specimens were subjected to three concentrations of colchicine (0.1, 0.5 and 1%) alongside five alfalfa cultivated cultivars. in the concentrations of 0.1% and 0.5%, a similar level of increase and pattern was observed in the two autotetraploids medic categories. increasing of concentration from 0.1% to 0.5% resulted in a more pronounced augmentation of comet parameters. autotetraploids induced by the two mentioned colchicine concentrations exhibited increases in the value and pattern of the three comet parameters compared to the cultivated cultivars and the two categories medics in diploid level. at the concentration of 1% colchicine, only two annual medic species produced tetraploids showing very pronounced augmentation of comet parameters in comparison with 0.1% and 0.5% of colchicine. changes in patterns and values of the three parameters in induced tetraploids compared to cultivated alfalfa  and the two categories medics in diploid level, demonstrate differential effects of damages of colchicines from one concentration to another. a new variability in each concentration change will be expected.