Development of an Efficient Regeneration System for Egyptian Cultivar(s) of Barley (Hordeum vulgare L.)

Abstract

Cultivated barley (Hordeum vulgare L.) belongs to the Triticeae in the grass family, Poaceae. Barley ranks as the world’s fourth most important cereal crop after wheat, maize and rice. It is grown over a wide environmental range than any other cereal crop. It is more tolerant to drought, summer frosts, saline and alkaline soils than other cereals; the grain is used for human food, animal feed and malt (FAO, 1998). Although barley is an important member of the cereal crops, it lags behind in gene transfer technology with regard to the introduction of elite agronomic traits such as disease and herbicide resistance. Non-sexual transfer of DNA to cereal species such as Hordeum vulgare L. has historically been problematic, chiefly because of problems encountered during attempts to regenerate cultured transgenic cells. Frequently, few or no plants can be recovered following selection for transformed cells, or only albino can be recovered (Lemaux et al., 1999). The recovery of fertile plants from transgenic callus is a critical component of many cereal transformation systems (Bregitzer et al., 1998; Hussein et al., 2004; Assem et al., 2008). Efficient regeneration of plants from transformed embryogenic callus is often limited to specific genotypes that exhibit vigorous plant regeneration (Bregitzer et al., 1998).
Improved plant regeneration from elite barley cultivars will facilitate their genetic transformation. The media composition is an important key factor influencing the regeneration ability of different genotypes. Different media compositions have been applied by Bregitzer (1992) and Hussein et al. (2004). Therefore, it is necessary to optimize the regeneration conditions for the Egyptian cultivars.
The objectives of the present investigation were: to establish an efficient regeneration system for some Egyptian barley genotypes using immature embryos as explants, and to evaluate the effect of different media composition on the embryogenic response and regeneration ability of the barley genotypes.