Callus Induction and Plant Regeneration from Immature Embryos of Sweet Sorghum (Sorghum bicolor Moench)

BACKGROUND AND OBJECTIVE: Regeneration of plant through tissue culture technique is a critical process in transformation of plants. This study sought to establish the effect of genotype and auxin concentration on callus induction from different sweet sorghum genotypes (IESV92008DL, IESV92001DL, IESV92021DL, ICSV700 and ICSV93048). MATERIALS AND METHODS: In this study, MS medium supplemented with five levels of the hormone 2,4-D (0, 1, 2, 4 and 6 mg L(-1)) to assess the effect of the hormone 2,4-D on callus induction and regeneration was used. RESULTS: The highest callus induction frequency was observed at 2 mg L(-1) 2,4-D for all the genotypes, IESV92008 gave the highest callus induction frequency among all the genotypes at 2 mg L(-1) 2,4-D. The lowest callus induction frequency was observed 0 and 6 mg L(-1) for all the genotypes, the two genotypes ICSV700 and IESV92021 were observed to give the lowest callus induction frequency among all the genotypes used in this study. Embryogenic callus induction frequency was observed to be higher at 2 mg L(-1) 2,4-D and the genotype IESV92008 gave the highest callus induction frequency among all the genotypes used. Induction of shoots was achieved in MS medium supplemented with 3 mg L(-1) 6BA and 1 mg L(-1) IAA, the highest regeneration efficiency was obtained from the three genotypes ICSV93048, IESV92008 and IESV92001, respectively. CONCLUSION: This study discovers the importance of the auxin 2,4-D on callus induction and regeneration of sweet sorghum and this will help the researcher to develop protocols for transformation of sweet sorghum.