Abstract
M.Tech.
Sorghum [Sorghum bicolor (L.)] is classified as a relatively recalcitrant crop due to its
poor amenability to in vitro and genetic manipulation. An efficient and reproducible
in vitro plant regeneration method is vital for a successful transformation of any crop.
Plant regeneration and transformation of eight selected elite sorghum genotypes was
studied. Immature zygotic embryos were used as explants and cultured on two
different callus induction media. Three genotypes ICSV1111N, SRN39 and P898012
were found to be highly regenerable producing 5.99; 5.1 and 4.74 regenerants per
explant respectively on the G2+L-proline callus induction medium. The eight elite
sorghum genotypes were co-bombarded with the uidA reporter gene and manA
selectable marker gene. Bombarded immature zygotic embryos were selected on
G2+L-proline callus induction medium supplemented with mannose as a selective
agent. PCR Positive transformants were only obtained from genotype P898012.
Furthermore the genotype P898012 was stably transformed with a lower DNA
amount of manA minimal transgene. The manA gene presence was confirmed with
PCR and southern blot analyses and a transformation efficiency of 0.38% was
attained. The fertile transgenic plants displayed simple integration patterns, and the
gene was also inherited to the T1 progeny of manA resistant trasnsformants in a
Mendelian fashion.