الفهرس 
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Abstract
Stem nodes of cassava (Manihot esculenta Crantz), American cultivar, were treated with different concentrations of clorox at different times (10, 20 and 30 % clorox for 5, 10 and 15 min). The lowest significant contamination and the highest significant survival percentages were recorded with 20% clorox for 15 min. Sterilized and survival nodal explants were cultured on MS medium supplemented with different concentrations of BA and Kin (0.1, 0.3, 0.5 and 1.0 mg L-1 -#102;-#114;-#111;-#109; each one alone) incombination with 0.05 mg L-1 of NAA. Maximum number of shootlets per explant (5.67) was achieved on MS medium supplemented with 1.0 mg L-1 BA + 0.05 mg L-1 NAA (proliferation medium). For shootlets multiplication, each shootlet was re-cultured on proliferation medium for two subcultures to investigate the effect of number of subcultures on multiplication rate. Maximum multiplication rate (~ 110 shootlets per nodal explant) was obtained after 75 days of culturing. For shootlets roots formation different concentrations of NAA and IBA (0, 0.5, 1.0, 2.0 and 4.0 mg L-1 -#102;-#114;-#111;-#109; each one alone) were used. MS medium supplemented with 2.0 mg L-1 IBA achieved the maximum number of roots formation (10.2), root length (14.4 cm) with 100% rooting percentage. In vitro derived plantlets were successfully acclimatized on a mixture of peat moss and sand (1:1) which gave the highest percentage of survival transplanting (100%). In addition, callus cultures of cassava were successfully established. Leaf, stem and root explants of one month old in vitro growing plantlets of cassava were utilized for callus induction on MS medium supplemented with different concentrations of 2, 4-D (0, 5, 10, 15 and 20 mg L-1). The highest callus production was obtained when leaf explants cultured on MS medium supplemented with 15 mg L-1 2, 4- D -#119;-#104;-#101;-#114;-#101; it recorded the maximum values of frequency of callus formation (100%), fresh/dry weights (6.3, 0.581g/jar) and dry matter content (9.2%) with significant differences between treatments. Induced callus was transferred to regeneration medium containing different concentrations of BA, 2iP and TDZ (0, 0.1, 0.5 and 1.0 mg L-1 -#102;-#114;-#111;-#109; each one alone). The highest significant regeneration percentage and number of regenerated shootlets (73.3% and 2.2, respectively) were observed on MS medium supplemented with 1.0 mg L-1 TDZ. The molecular characterization of the in vivo growing plants and the in vitro derived plantlets (in vitro propagated and regenerated plantlets) was performed. Random Amplified Polymorphic DNA (RAPD) was used to indicate the differences between them using three primers (AM7, AM8 and AM9). Using the primer AM7 gave the highest percentage (100%) of polymorphism. The primer AM7 showed that there were no differences between in vitro derived plantlets and the mother plant. Also, protein analysis was performed to detect the differences between mother plants and in vitro regenerated plantlets. There was polypeptide band (36 kDa) was over expression found in in vitro regenerated plantlet and not detected in in vivo plant. So, the differences between in vivo plant and in vitro regenerated plantlet were not clear. The results demonstrated that there were not observed variations between them. These results confirmed that tissue culture technique was providing safety for in vitro propagation of cassava plant.