Abstract
This study investigated the effect of grafting on the vegetative growth and reproductive development of tomato plants under controlled prolonged heat stress conditions. The heat tolerant tomato cultivar (cv.) 'Summerset' and the eggplant cv. 'Black Beauty' were selected as rootstocks and the heat sensitive tomato cv. 'UC 82-B' as scion. Grafted (tomato/tomato (T/T), and tomato/eggplant (T/E)) and non-grafted plants were grown under high (37/27 degrees C day/night) temperature and control (26/20 degrees C) temperature conditions in growth chambers. The experiments were conducted twice with the same conditions. This study indicated that grafted plants developed better under heat stress conditions than the non-grafted ones. T/E plants, for instance, showed significantly higher values of chlorophyll fluorescence at late fruiting stage, greater leaf area, leaf fresh and dry weight, number of pollen grains per flower and lower values of electrolyte leakage than non-grafted 'UC 82-B' at 37/27 degrees C. Also T/T plants had a better vegetative growth than 'UC 82-B'. However, there was no positive effect on reproductive traits including yield due to grafting. Further combinations with good productive scions and heat stress tolerant rootstocks need to be tested.