A melon genotype with superior competence for regeneration and transformation

Transformation efficiency of melon is low and is still regarded as a challenge. In this paper, the regeneration and transformation response of 'BU-21/3', a newly characterized melon breeding line, is described. The line seems to be superior in this regard to previously evaluated genotypes. Agrobacterium-mediated delivery of the GUS or GFP reporter genes into cotyledon explants was used to evaluate efficiency of transient and stable transformation. Good transient expression was observed, and stable transformation frequencies of 0.4-1.5 transgenic shoots per explant were obtained. Transgenic plantlets were transferred to a contained greenhouse as early as 8-10 weeks after transformation. Transgenic plants are fertile and exhibit a true-to-type phenotype. The 'BU-21/3' line may become a useful tool for the facilitation of transgenic breeding in melon.