Evaluation of two potential Cucumis spp. resources for grafting melons

Cultivation of Cucumis melo is hampered by soil stresses. Grafting is used to overcome these limitations. Different cucurbits belonging to several genera have been used as rootstocks for melons: Cucurbita, Lagenaria, Luffa, etc. However, negative effects on fruit quality appear in some rootstock-scion combinations. The selection of new resistant rootstocks that do not cause this negative impact in quality is necessary to improve melon cultivation. In this work, we evaluated two rootstocks, closer genetically to melon scions than those usually employed: a) an F1 hybrid between a commercial melon (C. melo subspecies melo var. inodorus market class Piel de Sapo) and one exotic accession (C. melo subspecies agrestis var. chinensis) with resistance to Monosporacus cannonballus, the causal agent of melon vine decline, and with a certain level of tolerance to Fusarium oxysporum f. sp. melonis race 1.2, that causes Fusarium wilt, and b) an accession of Cucumis metuliferus, highly resistant to M. cannonballus, F. oxysporum 1.2 and evaluated and classified as highly resistant to Meloidogyne spp. in this work. Grafting compatibility of these two selected genotypes with commercial melons was good. All grafted plants displayed higher vigour and earlier flowering than ungrafted plants. Fruits from plants grafted onto C. metuliferus showed similar quality than those from ungrafted/selfgrafted plants. However, fruits from plants grafted onto the F1 (inodorus × chinensis) had in this experiment lower brix degree than the ungrafted controls. The resistance to soil borne pathogens found in C. metuliferus and the good performance regarding plant development and fruit quality of the scions indicate that this species is a promising rootstock for melons.