The genetic basis of pH, colour and soluble solids in processing tomato is examined . In a first experiment, aimed at identifying the base populations with which to start selection, parents, F, and F2 progenies of an 8 x 8 diallel cross without reciprocals were tested .
The results indicate that additive, dominance and additive x additive epistatic effects were noticeable for the three characters . Higher order interlocus interactions were also detected .
As to the soluble solids, a trait for which higher order epistatic effects were less marked, the breeding potential of the cross combinations was assessed by calculating the expected mean values at the F . generation. Some cross populations having C 33' or C 35' as parent appeared to be superior .
A second experiment was conducted to collect data on the heritability of the foregoing qualitative traits by utilizing the regressions of F 3 offspring on F2 Parents . The low heritability coefficients observed would suggest the ineffectiveness of individual selection in early generations .
In both the F2 and F3 generations rather low correlation coefficients among the three quality traits were observed .