RESPONSE OF GRAFTED AND SELF-ROOTED TOMATO PLANTS TO SALINE CONDITIONS IN CLOSED SUBSTRATE SYSTEM

Grafting could be used as a means to alleviate salt stress in some greenhouse vegetables if appropriate rootstock is selected. In this research, the response of tomato rootstocks ‘Beaufort’ (L. esculentum × L. hirsutum) and ‘Resistar’ (L. esculentum) against to salinity was compared with self grafted ones (cv. Gokce F₁) in a PE covered greenhouse during the autumn and spring season of 2007-2008. Plants were grown in perlite (6 L plant^-1) with the density of 3.5 plants m^-2. The electrical conductivity of the nutrient solution supplied to the plants, which had a standard composition for tomato, was adjusted to 2.0 (control), 6.0 or 10.0 dS m^-1 by adding 0, 42 or 84 mmol L^-1 NaCl in order to determine rootstock-salt reaction. The experimental design was randomized parcels with 2 factors with 3 replicates. The results showed that rootstocks increased plant height, stem diameter, root and shoot fresh and dry weight, total and marketable yield. These parameters decreased dramatically with the increase of salinity. Salinity stress especially reduced mean fruit weight and increased amount of nonmarketable fruits. Although higher yield was obtained at 2 dS m^-1 in both growing seasons, the plants grafted onto Beaufort had the highest yields under saline conditions. It was concluded that grafting could increase plant vigor and yield resulting in better performance under saline conditions, however detrimental effect of salinity was more severe in spring season.