Morphogenetic Response of Cotyledon and Leaf Explants of

Callus cultures from cotyledon and leaf explants of a Spanish cultivar of melon (Amarillo Oro) were tested for growth and morphogenic capacity on several culture media with different concentrations of IAA (indole-3-acetic acid) in combination with 1.0 mg.L-1 BA (6-benzylaminopurine) or 6.0 mg.L-1 KIN (kinetin). The best results were achieved with cotyledon explants. The leaf explants presented low bud formation capacity. Variability of organogenic response on cotyledons of different age (7, 5, 3 and 1-day-old) was evaluated. The age of explant had a significant influence on bud induction. Cotyledon explants from 7-day-old seedlings showed higher organogenic index and development of shoots when cultured onto MS medium supplemented with 1.5 mg.L-1 of IAA and 1.0 mg.L-1 of BA. The effect of cut type of cotyledonary explants on organogenic response was also investigated. Explants cut transversally showed the best results. The addition of copper sulfate in the culture medium promoted a qualitative improvement of the regenerated shoots