Selection of superior bread wheat genotypes based on grain yield, protein, iron and zinc contents under normal irrigation and terminal drought stress conditions

The selection of high-yielding genotypes with high micronutrient and protein contents can play a major role in reducing protein-energy and micronutrient malnutrition. In this study, 20 bread wheat genotypes were examined under normal irrigation and end-season water deficit stress conditions. The grain yield (GY), thousand-kernel weight (TKW), protein (PR), iron (Fe), and zinc (Zn) contents were determined. The data were analyzed using the genotype by yield*trait (GYT) biplot method, and the superiority index was calculated from the integration of all yield-trait combinations. According to the results, the polygon view of GYT biplot under normal irrigation conditions showed that G20 was the best genotype in combining GY with TKW and PR contents. The G19 was the best genotype in combining GY with Fe and Zn contents. Under end-season water deficit stress, G20 was the best genotype in combining GY with TKW and Fe content. In addition, the G6 was the best genotype in combining GY with PR and Zn. The average tester coordinate (ATC) view of GYT biplot showed that there is not any genotype that was higher than the average yield-trait combination. However, G20 and G19 were relatively superior to other genotypes in this study. According to the superiority index, G20 and G19 genotypes were superior. Based on our results, G20, G19, and G6 genotypes were the best genotypes in combining GY with all or some evaluated traits, in two conditions. Therefore, they can be considered in genetic biofortification programs or variety introduction.