Yield and Compositional Profile of Eggplant Fruits as Affected by Phosphorus Supply, Genotype and Grafting

The present experiment addressed the effects of two phosphorus regimes (30 and 90 kg ha(-1), hereafter P-30 and P-90) on yield and composition of eggplant fruits in 'Birgah' and 'Dalia', whether or not these cultivars were grafted onto Solanum torvum 'Espina'. The P-30 regime did not reduce yield, and promoted fruits' dry matter and total phenols content, along with their concentrations of macronutrients, mesonutrients (S and Na) and micronutrients (mostly Cu, B, Zn); however, their Fe concentrations were depressed. The rootstock 'Espina' increased fruit yield, dry matter content, epicarp chroma (in 'Birgah') and Ca content, together with their concentrations of B and Zn (especially at P-30), but reduced their Fe content, mostly under P-30. Thus, the reduced P supply and grafting proved to be effective tools to enhance fruit yield, carpometric and almost all nutritional traits in eggplant, in a framework of more sustainable crop management. However, the reduced fruit concentration of Fe suggests that the affinity of the rootstock with specific micro minerals should be taken into account, along with the option to adopt complementary practices (e.g., targeted micronutrient fertilizations) to manage the micro mineral composition of eggplants.