Hossein ZEİNALZADEH TABRİZİ

Article | 2023 | Ecological Genetics and Genomics28

Spring oilseed rape is one of the major oilseed crops produced in different regions of Iran's tropical climates. Because of the various climatic and geographical conditions of the tropical areas of Iran, it is necessary to release high-yielding cultivars with broad adaptability to the various tropical regions. The main objective of this study was to identify high-yielding and stable spring oilseed rape genotypes among some new oilseed rape genotypes via analysis of genotype by environment interaction using the GGE biplot model. To this end, multi environmental trials (METs) were conducted across 16 environments. Twenty genotypes com . . .posed of two check varieties as well as eighteen promising oilseed rape lines which were selected through preliminary experiments previously were examined in this study. Trials were conducted in the north and south tropical climate regions of Iran in a format of RCBD with three replications during the 2018–2019 and 2019–2020 growing seasons. The mean grain yield of each genotype was calculated after harvesting. Graphical representations of grain yield using heatmap showed that all the genotypes performed differently across all environments. The grain yield across environments ranged from 1824 kg ha−1 (E11: Dezful) to 3610 kg ha−1 (E5: Moghan) while it ranged from 2416 kg ha−1 (G18: SRL-96-25) to 3148 kg ha−1 (G10: SRL-96-17) across genotypes. The combined ANOVA indicated that grain yield was notably affected by genotype, environment, and G × E interaction factors. The relative contribution of variations demonstrated that the environment contributed the largest total variation, followed by the G × E interaction and genotype. GGE-biplot efficiently identified genotypes SRL-96-17 (G10) and SRL-96-11 (G5) as high-yielding and stable genotypes utilizing which-one-where and mean versus stability biplots. Additionally, these genotypes represented the minimum distance from the hypothetical ideal genotype that confirms the superiority of new promising lines identified in this study. Therefore, G10 and G5 can be recommended as well-performing genotypes for regions with tropical climates. Keywords: brassica napus; multi-environmental trials; stability analysis; superior genotype; tropical region More less