STM Article Repository

Egyptian clover (Trifolium alexandrinum) has limited genetic variability. Efforts to induce genetic variability through interspecific hybridization in the species have failed due to incompatibility barriers. Present study was taken up to identify the suitable media and development stages for in vitro embryo development. Embryos collected at different developmental stages were cultured in six different culture media. These media differed in basal composition, hormonal concentrations and sucrose content. Globular embryo was observed 2-3 days after pollination (DAP) followed by heart shaped embryo in 4-5 DAP, torpedo shaped embryo in 5-7 DAP and cotyledonary stage in 7-9 DAP. Highest plantlet regeneration was observed from heart shaped embryos on EC3 media (75.2% of germinated embryos). Callusing was observed in germinated embryos in all the media that supported germination. However, media EC1 and EC2 showed higher callusing response. Torpedo shaped embryos responded better in EC3 media showing 60% germination and 78.9% plant regeneration. Considerably good callusing response to culture conditions in all the media EC4 and EC1. Cotyledonary stage gave highest response to culture conditions in all the media combinations for embryo germinations as well as for plantlet regeneration. EC3 medium with MS basal salts containing only Kinetin (0.5 mg/l) and moderate sucrose (3%) was the best for embryo germination. EC4 media with high adenine and high sucrose supported high callusing and reduced germination.