In order to detect gene action and epistatic effects
for drought tolerance indicators, 22 diverse genotypes of durum wheat
were used in a randomized complete block design with three replications
under rainfed and irrigated conditions in the Agricultural Research Center
of Kermanshah, Iran. Analysis of variance revealed enough genetic variation
and possibility of selection between genotypes. Mean comparison, using
Duncan multiple range test, indicated that genotypes 12, 13 and 21 were
suitable in drought conditions. In three-dimensional plot, based on STI
index, genotype 21 was grouped as a one cluster. Triple test cross analysis
indicated epistatic effects for heading date, ruin irritability and proline
content in the rainfed condition. Both additive and non-additive gene
actions were significant for grain yield, proline content and ruin irritability
in the water stress condition. For these traits, selection in segregating
generations and hybridization breeding methods were offered. Only additive
gene action was predominant for heading date in the rainfed condition.
Thus, selection in early segregated generations and massive selection
are considered. Higher D than H for all characters was showing incomplete
dominance. Correlation coefficient(r) between sums and differences of
lines were non-significant, indicating ambidirectional nature of dominant
genes between lines.
E. Farshadfar, S. Mahjouri and M. Aghaee, 2008. Detection of Epistasis and Estimation of Additive and Dominance Components of Genetic Variation for Drought Tolerance in Durum Wheat. Journal of Biological Sciences, 8: 598-603.