The results obtained for the parental, F
generations of a 10 × 10 diallel set (excluding reciprocals) of durum wheat revealed that there were significant differences between all the hundred genotypes for all the characters. The genotypes represented a wide range of expression for almost all the characters. High estimates of GCV (genetic coefficient of variation) were observed for the number of effective tillers, grain yield per plant, harvest index and 1000-grain weight. The low values of GCV recorded for days to heading, grain protein content and plant height indicated their limited scope for improvement. High heritability (h
) values ranging from 92.27% (grain yield/plant) to 99.00% (protein content) were observed for all the characters. The highest expected GA (genetic advance) as a percentage of the mean was manifested for harvest index, followed by plant height, number of effective tillers per plant and grain yield per plant. These traits also possessed high estimates of heritability, indicating that most of the variation in these characters was due to additive gene effects. For protein content high heritability was observed with low genetic gain, indicating non-additive gene effects. Thus, a systematic approach based on selection for harvest index, plant height and number of effective tillers per plant on the basis of high
performance would be the most effective approach for improving the yield level of durum wheat. The wealth of variability available in the hybrid populations offers good prospects for its improvement in the near future.