Grafting Compatibility and Environmental Conditions on Soilless Eggplant (Solanum melongena) Grown in the Mediterranean Greenhouse

Grafting techniques represent an efficient tool to enhance plant growth and development. The study aims to explore the effects of different grafting combinations on the growth of eggplants under diverse greenhouse conditions. Eggplant cultivar Black bell (Bb) was employed as scion, while the hybrid F1 Beaufort (Be) and Solanum torvum (To) were utilized as rootstock. The hypothesis behind this study pertains to grafting incompatibility with Beaufort F1. It postulates that this incompatibility can be mitigated by manipulating soil and greenhouse temperatures. The experimental factors encompassed plant combinations (Bb, Be/Bb and To/Bb), as well greenhouse and substrate temperature (both cold or heated). The Be/Bb combination showed higher values of plant vegetative traits, but it exhibited low grafting compatibility. Additionally, physiological analysis confirmed the presence of excessive growth and vegetative disorder within the Be/Bb combination. Examination of the xylem vessels revealed notable differences between the grafting combination involving Bb and the rootstock F1 hybrid Be/Bb, compared to the one with To/Bb and the non-grafted Bb. Specifically, the area, diameter and number of xylem vessels were approximatively 45% higher in Be/Bb than in To/Bb and the non-grafted Bb. Furthermore, a robust linear correlation was observed between plant height with morphometric and physiological traits, except fruits sets. This study lays the basis for a novel protocol for agriculture, addressing the excessive vegetative growth in rootstocks regulating air and substrate temperatures.