Influence of osmotic stress, physicochemical factors and nitrogen supplements on embryogenesis and plantlet formation in Guizotia abyssinica Cass. (Niger)

An efficient protocol for somatic embryogenesis was developed for the edible oilseed crop Guizotia abyssinica Cass. (cv. IGP 76). Induction and proliferation of callus was achieved from cotyledonary explants on MS medium amended with 1.5 mg l−1 6-benzyladenine (BA) and 0.5 mg l−1 naphthalene acetic acid (NAA). Several auxin/cytokinin combinations, physical conditions, osmotic stresses and supplementary components, viz., amino acids and casein hydrolysate were tested for induction of embryogenic callus. Higher frequency of embryogenic calli (73.7 %) and somatic embryos per culture (22) were observed on MS + 1.5 mg l−1 BA + 0.5 mg l−1 NAA + 0.5 % NaCl. Histological analyses showed typical globular and other stages of embryo development. The MS medium lacking growth regulators was best for the maximum germination of embryos (53.4 %) and formation of plantlets (65.4 %). Regenerated plantlets were acclimatized and transferred to the field with 62 % survival rate. © 2014, Indian Society for Plant Physiology.