Resumen
Measurement of physiological traits can be used to monitor plant water status, for irrigation scheduling or to predict the expected yield in open-field production of vegetables. This study evaluates the changes in stomatal conductance, chlorophyll fluorescence (Fv/Fm), relative chlorophyll content (SPAD), and canopy temperature at different stages of development of processing tomato to show their relationships with the yield and quality under well-irrigated, deficit irrigated, and non-irrigated conditions. Under non-irrigated conditions, during flowering with fruit setting and early fruit development the highest canopy temperature, lowest stomatal conductance, and Fv/Fm were measured, while the SPAD value was the highest. Under this condition, the correlation between the SPAD value, fruit weight, and marketing yield was positive, but it was negative with the total soluble solid (°Brix). During flowering with fruit setting, under deficit irrigation conditions a close significant positive correlation was found between the SPAD value and the fruit weight, marketing yield, and vitamin C content of fruits. During this period, under regularly irrigated conditions, the SPAD, Fv/Fm, and canopy temperature related to stomatal conductance. Stomatal conductance had significant influence on yield and quality under non-irrigated and well-irrigated conditions while the SPAD value and canopy temperature had significant influence on under deficit irrigated conditions.