Methods of transformation

Early work by Guri and Sink,⁶⁶ Rotino and Gleddie⁶⁷ and Rotino et al.⁶⁸ demonstrated the feasibility of transformation of eggplant via A. tumefaciens with a transformation efficiency of 7% in the latter case. However, Billings et al.⁶⁹ wereunsuccessful in transforming their experimental material using one of these two methods. After studying the effects of growth regulators, they devised an improved method that included thidiazuron and gave an transformation efficiency of 20.8%. The transformation efficiency seems to depend strongly upon the geno type. For instance, La Porta et al.⁷⁰ were unable to transform their lines using the protocol of Billings et al.,⁶⁹ which proved very efficient with some other genotypes,^{71, 72} while they obtained a transformation frequency of 8.3% with the protocol of Rotino and Gleddie.⁶⁷ It appears therefore that eggplant is not a recalcitrant species, but care must be taken in adapting the transformation protocol to the genotype.