Published online by Cambridge University Press: 27 March 2009
The joint scaling test of Cavalli (1952) and the six-parameter procedure of Jinks & Jones (1958) were applied to test the adequacy of the additive-dominance model and to estimate various main and interaction gene effects for five characters, namely, final plant height, ear length, number of spikelets per spike, number of grains per spike and yield per plant, in three wheat crosses (Kalyan Sona × Norteno 67, Norteno 67 × WL 212 and K. Sona × Moti). Goodness of fit of the model varied from cross to cross for the same character except for number of grains per spike and yield per plant for which the model was inadequate for all three crosses. The two methods were in complete agreement regarding the presence of epistasis in the material. Among the interaction parameters, the component [1] showed the greatest effect for most of the characters in all three crosses where there was evidence of epistasis.