The four grafted melon genotypes; Ismaillawi, Ananas El-Dokki, PI 124111 and the F1 (Ismaillawi PI124111), on Lagenaria siceraria rootstocks were found to have higher mean values of all studied developmental characters than the respective values of ungrafted genotypes. The differential increase in developmental characters in different scion genotypes revealed that the PI124111 followed by the F₁ (Ismaillawi x PI124111) were the best combination with this rootstock under irrigation conditions using under-ground water of EC 1.7 m.mhos. In vitro translated mRNAs isolated from leaves of dark-treated grafted and ungrafted melon genotypes on Lagenaria siceraria rootstock, showed that after one week of grafting date, mRNA samples of F₁ (Ismaillawi x PI 124111) expressed two more protein bands (108.4 and 41.7KD) than those of ungrafted plants. After two weeks of grafting date, mRNAs of leaves of dark-treated grafted F₁ plants showed to have the transcript of additional third protein band with a molecular weight of 67KD which was also found to be absent of in vitro translated mRNAs of respective ungrafted plants. The differential display of in vitro translated mRNAs of roots and leaves of both scion and rootstock of dark-untreated plants showed that the two unique protein bands (108.6, 42KD) which were also appeared in L. siceraria roots found in the in vitro translated mRNA samples of leaves of F1 melon scion grafted on L. siceraria rootstock. The results suggest that both the two transcripts of mRNAs either might be migrated from the roots of L. siceraria rootstock to scion leaves or stimulated to be transcribed in scion leaves as a response of signals originated in roots of the rootstock. Positive subtractive enriched cDNA fragment, after two rounds of PCR amplification, was observed with a size of about 200bp which will be used as a probe for fishing a complete cDNA involved in enhancing the developmental characters of grafted melon plants on L. siceraria rootstocks.