Study on adaptability and yield stabilityof durum wheat varieties in uniform regional yield trials in cold dryland areas.

In order to study of adaptability, yield stability and tolorance to environmental stresses (drought and heat) of dryland promising durum wheat genotypes, this study was conducted during two cropping seasons (2001-2003) in two separate experiments and three regions of cold dryland area(Maragheh, Sararood and Ghamloo). Experiments included seven promised durum wheat genotypes with one durum wheat check (Zardak) and three bread wheat genotypes (one landrace, Azar-2 and Sardari) and excuted in RCBD with four replications. In first experiment in each location simple ANOVN and combined ANOVN for two years had implemented. Lin and Binns parameter, coefficient of variation of grain yield and rank method were used for determination of stable genotypes. Results of combined ANOVA showed that year, location, genotype and interaction effects of Y _e L and Y_e L _eG were highly significant (P 0.01). The highest grain yield was belonged to first year (1.880 t/ha), Sararood(2.640t/ha) and after bread wheat varieties Azar ¡V2(2.320t/ha) and Sardari (2.270t/ha) line no.4 (61-130/414-44//¡K) with 1.960t/ha has the highest grain yield among durum wheat genotypes. Results of stability analysis with lin and Binns method showed that lines no.8, 7, 6 and 3 had the highest stability comparing the bread wheat genotypes and durum check. The results of rank method showed that all durum genotypes had the lowest comparing with Zardak (check) and the lowest SDR was belonged to line no. 4. Second experiment excuted under rainfed and irrigated (sowing date and spike emergence date) conditions. Quantitative criteria of stress resistance as: stress tolerance index (SSI) and geometric mean productivity (GMP) were used for genotypes response to stresses. Results of second experiment showed that among the durum wheat genotypes line no. 4 has the highest tolerance to environmental stresses (heat and drought). The conclusion of results showed that line no. 4 can be recommended for cold dryland areas of Iran.