Effect of grafting on morphology of Solanum melongena and Solanum torvum Sw. hybrids

Solanum melongena is susceptible to numerous diseases and parasites, particularly the bacterial and fungal (Fusarium and Verticillium) wilts, nematodes and some insects. Solanum torvum is resistant to Verticillium wilt, root-knot nematodes as well to some mycoplasmas. It is known that interspecific hybrids resulting from cross hybridization of these species are almost sterile. The objective of this study was to investigate the effect of grafting on the morphology of interspecific diploid and tetraploid hybrid (Solanum melongena × Solanum torvum) plants. The plants of two interspecific hybrid genotypes (AU2/I-6, AU4/I-10) were obtained by in vitro germination of seeds produced by crossing Solanum torvum and the eggplant cultivar, ‘Faselis F₁’. The buds of these 2 interspecific diploids and 2 tetraploids (autotetraploid Kol53, amphidiploid U4/IV-I-4) genotypes that were obtained by colchicine application were grafted on ‘Pala’ and ‘Faselis F₁’ rootstocks. Then the grafted plants were grown in a glasshouse and the morphological characteristics were studied. In diploid genotypes, grafting significantly affected some properties of the plant; such as branch number, leaf blade width, and length, leaf lobbing, petiole length, leaf hair, inflorescence type, flower or bud number per inflorescence, calyx length, corolla number and width. However, the effect of grafting was not significant in tetraploid genotypes.