DEVELOPMENT OF A NEW INITIAL BREEDING MATERIAL IN SUNFLOWER (HELIANTHUS-ANNUUS L) USING DIRECT ORGANOGENESIS AND SOMATIC EMBRYOGENESIS

Immature zygotic embryos from three inbred lines of sunflower (Heliant hus annuus L.) were used as donor material for the induction of direct organogenesis and somatic embryogenesis. The scope of the spontaneous ly appearing somaclonal variation has been studied among the regeneran ts produced according to the method of Freyssinet & Freyssinet (1988), and was compared to the results obtained after gamma ray mutagenesis (7 and 10 Gy). Freshly excised immature zygotic embryos were used for irradiation treatment. Genetic changes occurring spontaneously during the regeneration procedure were observed for date of flowering, vegeta tion period, plant height, head diameter, 100() seed weight, kernel oi l content, and fatty acid composition. The mutagenic treatment had a m arked stimulatory effect on the frequency of the regenerants produced and the degree of the observed changes. The 7 Gy treatment was most ef ficient for the majority of the characters studied. The type of change s was correlated with the genotype. The degree and type of somaclonal variation, with or without mutagenic treatment, should be sufficient f or an application in the production of new breeding material.