Basal medium constituents and their concentration play an important role in growth and morphogenesis of plant tissues cultured in vitro. In this study effect of different inorganic nutrients (CoCl 2 , MnSO 4 , ZnSO 4 , CuSO 4 and AgNO 3 ) on callus induction and plant regeneration in Paspalum scrobiculatum and Eleusine coracana was examined. A 59 and 39 increase in regeneration response at enhanced levels of CuSO 4 was noted for kodo and finger millets, respectively. Significant improvement in plant regeneration was also observed with the increase in levels of Co and Mn. Addition of AgNO 3 to the basal medium also had a stimulatory effect on callus induction and plant regeneration. Optimization of nutrient level in the basal medium has highly significant role in obtaining maximum regeneration response from explants and callus culture.

Agrobacterium-mediated transformation protocol has been developed for Eleusine coracana (var. PR-202) by varying several factors which influence T-DNA delivery. Green nodular regenerative calli with meristematic nodules of seed origin were used as the target tissue for Agrobacterium tumefaciens-mediated gene transfer. The highest frequency of transformation (44.4%) was observed when callus was infected, co-cultivated and incubated at 22°C. Incorporation of higher level of CuSO 4 in the regeneration medium had significantly positive effect on the recovery of transformed plants. PCR analysis of T 0 and T 1 generation plants with nptII-specific primers revealed the amplification of nptII gene. Southern blot analysis of six regenerated plants confirmed selectable marker gene integration in three plants. This is a first report on Agrobacterium-mediated genetic transformation of finger millet and will pave the way for further studies in this and other millet crops.

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An efficient and reproducible protocol for Agrobacterium tumefaciens mediated genetic transformation was developed for kodo millet (Paspalum scrobiculatum L.) by optimizing various parameters. Agrobacterium strains EHA 105 and LBA 4404 harboring plasmids pCNL 56 and pCAMBIA 2300, respectively, provided the highest transformation efficiency. Addition of acetosyringone (AS) in infection medium (200 µM EHA 105, 250 µM–LBA 4404) and co-cultivation medium (50 µM) increased the transformation efficiency. Transient and stable expression of gus gene was confirmed with histochemical assay of infected embryos and leaves of transformed plants, respectively. The best GUS response was obtained by pretreatment of callus with an antinecrotic mixture (10 mg/L Cys + 5 mg/L Ag + 2.5 mg/L As) at infection time of 20 min followed by co-cultivation for 3 days (EHA 105) and 5 days (LBA 4404) in dark. Regenerated transgenic plants were obtained after 8 to 10 weeks of selection on callus induction medium (NAA 0.5 mg/L, BAP 1 mg/L) containing 50 mg/L Kan + 250 mg/L Cef and were rooted for 2 weeks on MS medium containing PAA (1 mg/L) and phytagel. The plantlets established in greenhouse showed normal growth. Therefore, the protocol developed in the present study can be used for development of improved varieties of kodo millet.