EFFECT OF CHEMICAL MUTAGENS ON TAGETES ERECTA

Two mutagenic reagents, Diethyl sulphate (DES) and sodium Azide (SA), were used to study their effects on the morphological characteristics of Tagetes erecta (L.) cvs. Petite Yellow and Hawaii , as well as  the possibility of  mutation induction  in the M1 and M2 generations. Seeds were treated with different DES and SA concentrations : 0 (distilled water) 1000, 2000, 3000, 4000 and 5000 ppm.  for six hours.
DES mutagen at low concentration (1000 ppm.) increased the seed germination percantage, while high concentrations (2000 - 5000 ppm.) decreased it .  No Petite Yellow plants were survived after being treated with the high concentration (5000 ppm.) treatment .  The DES concentrations of 1000, 2000 and 4000 ppm   caused decreases in the plant height of both cultivars in the M1- generation. The DES doses from 2000 to 5000 ppm. significantly decreased the plant height in M2- generation in Hawaii Cv.  There were no significant increases in the number of branches per plant in Petite Yellow , but there were significant differences in Hawaii in both generations. The concentration of 2000  ppm. DES  significantly  delayed the flowering in the M1- generation of Petite Yellow  while 1000 and 5000 ppm. concentrations delayed the flowering in the M1-generation of Hawaii . DES concentrations of 3000 and1000 ppm markedly  increased the  dry weight in the M2- generation of  Petite Yellow and Hawaii plants respectively.
                SA mutagen at low concentration (2000 ppm.) significantly  increased the percentage of germinated seeds, of Petite Yellow in the M2- generation.  There were no significant differences among the treatments on plant height of Petite Yellow , while there were significant differences in both generations of Hawaii . There were no significant differences between the effects of the different treatments on the number of branches and the number of days to flowering  in both cultivars . However, there were significant differences among  the treatments on the number of inflorscences per plant. The differences were not significant for the dry weight  of  both cultivars in both generations .
                Generally, the results had also indicated that DES and SA was effective in inducing morphological changes and mutations , and the induced changes were found to affect the following characters ; growth habit, flower colour and the number and size of ray florets .