The affect of medium component and embryo age on callus induction and plant regeneration from immature embryos of HR8 maize inbred line

SUMMARY

The effective regeneration system plays important role in plant transformation. In general, maize (Zea mays L.) is recalcitral plant in regeneration, except some high regenerable lines as A188, H99, HiII… which have been used for transformation. Besides, plant regeneration capacity depends on genotype. It was also affected by medium component and the other factors.

HR8 and HR9 are high regenerable lines were used in this study. There was no significant difference among callus induction rates for immature embryos cultured on MS or N6 medium containing 20 g/l sucrose, 2 mg/l 2,4-D, 100 mg/l casein hydrolysat, 25 mM L-proline, 10 mg/l AgNO₃ and 0.2% phytagel.

Incorporating 10 mg/l AgNO₃ into phytagel solidified N6 medium supplemented 20 g/l sucrose, 2 mg/l 2,4-D, 100 mg/l casein hydrolysat, 25 mM L-proline promoted callus production from cultured immature embryos of HR8 line. Under these conditions, approximately 90.5% of the xplants produced calli after 2 to 3 weeks incubation in the dark at 28⁰C and plant regeneration frequency was 26.6%. The optimum embryo age for scutellar callus initiation was 18-20 days post-pollination (approximately 1-2 mm size respective).

Pham Thi Ly Thu, Pham Minh Thoi, Le Huy Ham, Do Nang Vinh
Institute of Agricultural Genetics