Optimization of Ionic and Chelated Iron and Its Interaction with Disodium Ethylenediaminetetraacetic Acid for Enhancement of Plant Regeneration in Rice (Oryza sativa L)

Interactive effects of Fe₂(SO₄)3 and Na₂EDTA on callus induction and plant regeneration in indica rice (Oryza sativa cv Pusa Basmati-1) was investigated. Callus induction and subsequent plant regeneration from seed was obtained on MS medium supplemented with 11.31 µM 2,4-D and 2.68 µM NAA + 8.87 µM BAP respectively. Both the callus induction and the plant regeneration media were supplemented with different levels of Fe₂(SO₄)₃, Na₂EDTA and their combinations. Callus induction, its morphogenic potential, average number of regenerated plants as well as the appearance of the regenerants was influenced by the levels of Fe₂(SO₄)₃ and Na₂EDTA. Embryogenic callus could be induced in the presence of Fe₂(SO₄)₃ / Na₂EDTA. Iron was essential for plant regeneration. Non-chelated iron could induce callus formation as well as plant regeneration, yet the chelated form was more suitable. A higher level of Na₂EDTA in the regeneration medium was detrimental. Differential requirement of Fe₂(SO₄)₃ at induction and regeneration level was observed. Method of medium preparation affected the regeneration response. Nearly three fold increase in the number of regenerated plants was achieved with 0.05 mM Fe₂(SO₄)₃ + 0.1 mM Na₂EDTA at callus induction and 0.1 mM Fe₂(SO₄)₃+ 0.1 mM Na₂EDTA at plant regeneration and standard method of autoclaving.