By using two tomato genotypes, "227/1" (Fe chlorosis susceptible) and "Roza" (Fe chlorosis tolerant), and their reciprocal F-1, F-2 and BC1 generations, the inheritance of tolerance to leaf Fe deficiency chlorosis of Roza was studied. Plants were grown in a nutrient solution and subjected to 2.0 x 10(-6) M Fe EDDHA and 10 mM NaHCO3 to induce Fe deficiency stress by stabilization of pH to 7.8-8.2. A rating scale of 1-3 for chlorophyll was used and both monogenic and polygenic inheritance hypotheses were tested. Better responses to Fe deficiency, as measured by SPAD meter values, were obtained from the cross "Roza x 227/1" than from the reciprocal cross. Data from F-2 and BC1 suggest Fe chlorosis tolerance of Roza is to be controlled by polygenic loci with a relatively high additive effect.