Correlations, epistasis, and heterosis of plant height and internode length in barley

The correlation between total height and its components, and between these and yield components, and the presence of nonallelic interactions and heterosis were studied in barley by means of a 6 × 6 diallel cross. The estimation of interaction and heterosis parameters were made in P1, P2, F1, F2, B1, and B2 generations according to the Jinks and Jones model. Total height had a positive correlation with each internode length. The values of such correlations seemed to indicate that peduncle length could be a good index of total height. The plants with short basal internodes had less total height and longer intermediate internodes. The positive correlation of total height with yield and its components suggests that the selection for short culm and short basal internodes would be to the detriment of yield. The predominant interaction was of the duplicate type, the total height being the character with greater epistasis. In the crosses with heterosis, this was always positive. 'Albacete' × M-168 and A.1.-2 × M-...