Optimization of Callogenesis from Khardel Aswed Brassica nigra L. local Iraqi cultivar
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The current study was conducted to optimize callogenesis protocol for local cultivar of Brassica nigra. The results showed that all the sterilization methods were effective in controlling seed contamination. However, there were noticeable effects for the sterilization methods on the viability of the seeds. The treatment 70% ethanol for 1 minute followed by 30% Fas (contain 6% sodium hypochlorite) for 10 minutes was the best for seeds sterilization. Callus was induced from different explants from In vitro growing seedlings and they respond differently on the different callus induction media. The true leaf and the root explants gave hairy roots on MS medium supplemented with 0.5 mg.L-1 NAA + 2 mg.L-1 Kin which reduced the percentage of callus induction to 4% for both explants. The results also indicated that stem followed by cotyledon showed high percentage of callus induction than other explants (35%, 31%) respectively. Among the three callus induction media, MS medium supplemented with 2 mg.L-1 2, 4-D and 2 mg.L-1 Kin was the most responsive medium with an average of 40.25% callus induction. The interaction effect of the media and the explants on callus fresh and dry weights showed that stem explants grown on MS medium supplemented with 2 mg.L-1 2, 4-D and 2 mg.L-1 Kin gave significantly higher callus fresh and dry weights than other combinations and followed by cotyledon. According to callus color the calli that were induced from different explants on different media under light condition varied in color such as green, brown, pale yellow and greenish white. In conclusion stem and cotyledon of Khardel are the best explants for callus induction on MS basal medium supplemented with 2 mg.L-1 2, 4-D and 2 mg.L-1 Kin.
Keywords: 2, 4-D, Kin, NAA, stem, cotyledon, hairy roots, callus induction