Plant regeneration of some Egyptian maize genotypes from type II callus maintained under water stress conditions [electronic resource].

Includes references.

This study was carried out in an attempt to initiate a high embryogenic callus (type-II) in some Egyptian maize genotypes and to regenerate drought tolerant (DT) plants from DT calli. Four out of ten maize genotypes responded successfully to initiate type-II callus from the immature embryos, viz, the inbred lines Sd-7 and Sd-34, the single cross SC-10 and the three-way cross TWC-310 using N6 medium supplemented with 2 mg/12, 4-D, 100 mg/l casein hydrolysate, 2.3 g/l L-Proline, 15.3 g/l silver nitrate and 3% sucrose. Values of growth characteristics of type-II callus were gradually increased with increasing number of subcultures. Maintained callus on media containing increased concentrations of polyethylene glycol (PEG) inducing water stress showed a gradual decrease in all studied callus growth parameters. Calli of the crosses SC-103 and TWC¬310 had larger absolute values of growth traits than those of the inbreds Sd-7 and Sd-3 4 under all concentrations of PEG; which might be attributed to heterosis phenomenon. Plant regeneration of type-II callus was successfully achieved from the four genotypes, with a maximum regenerability in the three-way cross TWC-310. Exposing callus to increased drought stress conditions decreased the regeneration ability in a gradual manner. Plants regenerated from drought tolerant calli reached to maturity and their progenies will be evaluated for drought tolerance. Key words: Zea mays, type-II callus, regeneration, drought tolerance, immature embryo, in vitro selection.

Summary in Arabic.

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