Production of Rare Hybrids

Hybridization is a well established plant breeding procedure to obtain superior plants by combining useful characters distributed in different plants. However, cross-pollination does not always result in the formation of viable seeds. The cross may fail due to a pre-zygotic barrier to cross ability, which prevents fertilization, or the hybrid embryo may abort due to post-zygotic incompatibility. It is now possible to overcome both types of incompatibility barriers. Hybrid embryo normally aborts on account of the failure of endosperm development or due to embryo endosperm incompatibility, in such instances it can be excised from the young seed and cultured in-vitro. This technique was first used by Laibach to raise viable interspecific hybrids in Linum. Since then embryo culture also called embryo rescue has been successfully applied to several sexually incompatible crosses (e.g., Hordeum vulgare x H. bulbosum, Lycopersicon esculentum x L. Peruvianum)