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This study was conducted to evaluate the adaptability and grain yield stability of 26 durum wheat genotypes. The studied genotypes were investigated at the dryland research stations of Sararood, Gachsaran, Ilam, Moghan, and Khorramabad under rainfed and supplemental irrigation conditions (only in Sararood) during three cropping seasons (2021-22, 2022-23, and 2023-24). The results of the combined analysis of varance for grain yield showed that there was a significant difference for grain yield for the effect of genotype (G), environment (E), and GxE interaction at 1% probability level. The magnitude of the environmental effects indicates the different environments, which caused the iGxE and then, caused highly variation in the genotypic mean yields. The mean yield of genotypes in the experiment was 3635 kg/ha, ranging from 3166 kg/ha for the Zahab variety to 3929 kg/ha for breeding line G17. The genotypes G17, G14, G24, G22, G23 and G8 had an average yield of 3929, 3896, 3867, 3797, 3797 and 3773 kg/ha, respectively, with a yield advantage of 7%, 7%, 6%, 4%, 4% and 3% over the best check of the experiment (Saverz cultivar) with an average yield of 3656 kg/ha. According to the AMMI model, the breeding line G17 was among the top three choices in 12 out of 17 environments studied, which indicates the general adaptability of this line to most of the environment studieds. According to parametric and non-parametric statistics, the G17, G14, G24, G22 and G23 lines had the highest yield stability across environments. The results of the graphical analysis of the GxE interaction using the GGE biplot model showed that it was possible to group of tested environments into different environmental groups that provide specific adaptation for the genotypes. According to the GGE biplot model, the breeding lines G24, G17, G22, G21 and G10 lines showed the highest level of combination of mean yield and stability simultaneously. Also, breeding lines G14 and G16 with higher mean yield than grand mean had special adaptation to some environments of Kermanshah and lines G23 and G25 had special adaptation to some environments of Gachsaran, Ilam and Khorramabad. Some environments related to the Kermanshah, Gachsaran, Moghan, Khorramabad and Ilam showed a greater discriminating ability and representativenss view of environments than the rest of the environments, which characterized as ideal environments in this study. Based on the results, the selected lines had a significant advantage over the check varieties in terms of mean yield and stability, which indicates a genetic improvement in the durum wheat breeding program for stability and increased production compared to the check varieties.
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