SUNFLOWER TISSUE AND CELL-CULTURES AND THEIR USE IN BIOTECHNOLOGY

Sunflower is one of the major crops worldwide for oil and protein production. Until recently sunflower improvement has largely been achieved through classical sexual crossing. However, the germplasm of the cultivated sunflower being rather limited, the application of biotechnological techniques overcoming the sexual barriers would be desirable. The development of such technology largely depends on the ability to regenerate intact fertile plants from organs, tissues or protoplasts. An overview of plant regeneration by direct or indirect organogenesis and embryogenesis from explants, gynogenesis, anther culture and embryo rescue is presented. The use of these techniques, associated with several biotechnological methods such as somaclonal variation, screening for various characteristics, interspecific crossing or genetic transformation, designed to enrich the genome of sunflower, is described. Special attention is paid to protoplast technology. A presentation of plant regeneration from protoplasts is proposed and the main bootlenecks involved in this area are discussed. Finally, sunflower improvement through direct gene transfer and somatic hybridization involving protoplasts is reviewed.