1- Razi University
2- Lorestan Agricultural and Natural Resources Research and Education Center
2- Lorestan Agricultural and Natural Resources Research and Education Center
Abstract: (27 Views)
Background: Barley as one of the oldest cultivated crops in the world, belongs to the genus Hordeum and the family Poaceae with chromosome number of 2n = 2x = 14. According to the latest statistics of the Food and Agriculture Organization of the United Nations (FAO), barley covered approximately 46 million hectares worldwide in 2023, with a total production of about 145.7 million tons, ranking fourth among cereal crops after wheat, maize, and rice. Population growth and the necessity of ensuring adequate food supply, and more importantly achieving self-sufficiency in agricultural production in view of limited water resources and the reduction of cultivated areas, have made the development of high-yielding barley cultivars a major priority in agriculture. Genotype × environment interaction reflects the differential response of genotypes to the environmental conditions, meaning that the best genotype in one environment is not necessarily the best in another environment. Researchers have employed various criteria to investigate genotype × environment interaction, identify stable cultivars, and recommend them, which generally include both univariate and multivariate methods. Recently, the Multitrait Genotype–Ideotype Distance Index (MGIDI) and the Factor Analysis and Ideotype-Design–Based Genotype–Ideotype Distance Index (FAI-BLUP) have been proposed as two effective models for selecting ideal genotypes based on a set of measured traits. Therefore, the objective of this study was to identify stable rainfed barley cultivars among Iranian and European genotypes under diverse climatic conditions of western Iran using a combination of parametric, non-parametric, and multi-trait selection indices (MGIDI and FAI-BLUP).
Methods: Nine genotypes, including six European cultivars and three Iranian cultivars, were evaluated to determine grain yield stability of barley cultivars in western Iran. The experiment was laid out over two cropping seasons (2020–2021 and 2021–2022) at three locations in three provinces—Kermanshah, Lorestan, and Ilam—using a randomized complete block design with three replications under rainfed conditions. Agronomic management practices were applied uniformly across all environments. Combined analysis of variance was performed considering genotype and environment as a fixed and a random effect, respectively. For stability assessment, a set of univariate parametric indices (including Shukla’s stability variance, regression coefficient, deviation from regression, Wricke’s ecovalence, superiority index, desirability index, environmental coefficient of variation, and environmental variance) and non-parametric methods (including Kang’s rank-sum method and the Si and NPi statistics) were calculated. In addition, the two modern multi-trait indices MGIDI and FAI-BLUP were used to select superior genotypes based on a set of multi-trait indices related to grain yield and stability. Spearman’s rank correlation was used to assess relationships among stability indices and grain yield.
Results: The results of the combined analysis of variance indicated that the effects of environment and genotype × environment interaction were highly significant for grain yield, and that the major proportion of yield variation was attributed to the environment, whereas the main effect of genotype was not significant. This finding highlights the differential response of barley cultivars to variable environmental conditions and underscores the necessity of using stability indices. Consequently, selecting appropriate indicators without considering stability is not feasible. The results showed that the cultivars ALCE, SFERA, NURE, and AIACE, in addition to having grain yields higher than the overall mean, exhibited desirable stability and therefore they were identified as superior cultivars. In order to select simultaneously superior genotypes in terms of grain yield and stability, the multitrait selection indices such as MGIDI and FAI-BLUP were employed, and their results provided a more comprehensive perspective compared with single-trait approaches. The results of the MGIDI index indicated that the genotypes PANAKA and SFERA had the shortest distance from the defined ideotype and were therefore selected as desirable genotypes. In contrast, the results of the FAI-BLUP index showed that the genotypes ALCE and SFERA had the highest probability of similarity to the desired ideotype and were identified as superior genotypes. The selection overlap of genotype SFERA by both MGIDI and FAI-BLUP indices indicates its stable superiority from a multi-trait perspective. The difference in genotypes selected by these two indices also reflects their complementary nature; where MGIDI focuses more on traits balance, while FAI-BLUP, in addition to stability, places greater emphasis on yield improvement. Correlation analysis among indices also indicated that the PV (genotypic superiority index), CV (environmental coefficient of variation), and EV (environmental variance) had the greatest ability to discriminate stable and high-yielding cultivars. A notable point was the presence of significant positive correlations between the parametric and non-parametric indices. The strong correlation indicated substantial overlap and consistency between the parametric and non-parametric indices in identifying stable genotypes, confirming their agreement.
Conclusion: Overall, the results of this study demonstrated that the simultaneous use of parametric and non-parametric methods along with multi-trait indices can enable a more accurate and comprehensive selection of stable and superior barley cultivars for rainfed conditions in western Iran. The cultivars ALCE, SFERA, NURE, and AIACE were identified as genotypes with desirable stability and yield performance and can contribute effectively to breeding programs and to increasing the productivity of barley in rainfed regions. Multi-trait indices also proved to be highly practical complementary tools in the selection process, particularly when multiple traits are considered simultaneously.
Methods: Nine genotypes, including six European cultivars and three Iranian cultivars, were evaluated to determine grain yield stability of barley cultivars in western Iran. The experiment was laid out over two cropping seasons (2020–2021 and 2021–2022) at three locations in three provinces—Kermanshah, Lorestan, and Ilam—using a randomized complete block design with three replications under rainfed conditions. Agronomic management practices were applied uniformly across all environments. Combined analysis of variance was performed considering genotype and environment as a fixed and a random effect, respectively. For stability assessment, a set of univariate parametric indices (including Shukla’s stability variance, regression coefficient, deviation from regression, Wricke’s ecovalence, superiority index, desirability index, environmental coefficient of variation, and environmental variance) and non-parametric methods (including Kang’s rank-sum method and the Si and NPi statistics) were calculated. In addition, the two modern multi-trait indices MGIDI and FAI-BLUP were used to select superior genotypes based on a set of multi-trait indices related to grain yield and stability. Spearman’s rank correlation was used to assess relationships among stability indices and grain yield.
Results: The results of the combined analysis of variance indicated that the effects of environment and genotype × environment interaction were highly significant for grain yield, and that the major proportion of yield variation was attributed to the environment, whereas the main effect of genotype was not significant. This finding highlights the differential response of barley cultivars to variable environmental conditions and underscores the necessity of using stability indices. Consequently, selecting appropriate indicators without considering stability is not feasible. The results showed that the cultivars ALCE, SFERA, NURE, and AIACE, in addition to having grain yields higher than the overall mean, exhibited desirable stability and therefore they were identified as superior cultivars. In order to select simultaneously superior genotypes in terms of grain yield and stability, the multitrait selection indices such as MGIDI and FAI-BLUP were employed, and their results provided a more comprehensive perspective compared with single-trait approaches. The results of the MGIDI index indicated that the genotypes PANAKA and SFERA had the shortest distance from the defined ideotype and were therefore selected as desirable genotypes. In contrast, the results of the FAI-BLUP index showed that the genotypes ALCE and SFERA had the highest probability of similarity to the desired ideotype and were identified as superior genotypes. The selection overlap of genotype SFERA by both MGIDI and FAI-BLUP indices indicates its stable superiority from a multi-trait perspective. The difference in genotypes selected by these two indices also reflects their complementary nature; where MGIDI focuses more on traits balance, while FAI-BLUP, in addition to stability, places greater emphasis on yield improvement. Correlation analysis among indices also indicated that the PV (genotypic superiority index), CV (environmental coefficient of variation), and EV (environmental variance) had the greatest ability to discriminate stable and high-yielding cultivars. A notable point was the presence of significant positive correlations between the parametric and non-parametric indices. The strong correlation indicated substantial overlap and consistency between the parametric and non-parametric indices in identifying stable genotypes, confirming their agreement.
Conclusion: Overall, the results of this study demonstrated that the simultaneous use of parametric and non-parametric methods along with multi-trait indices can enable a more accurate and comprehensive selection of stable and superior barley cultivars for rainfed conditions in western Iran. The cultivars ALCE, SFERA, NURE, and AIACE were identified as genotypes with desirable stability and yield performance and can contribute effectively to breeding programs and to increasing the productivity of barley in rainfed regions. Multi-trait indices also proved to be highly practical complementary tools in the selection process, particularly when multiple traits are considered simultaneously.
Keywords: Genotype × environment interaction, Stability analysis, MGIDI index, FAI-BLUP index, Hordeum vulgare L.
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