Abstract
Introduction: Drought stress in dryland wheat cultivation, where the plant solely relies on rainwater, can have a detrimental effect on plant growth. Given the lengthy duration of breeding projects, identifying stress-tolerant breeding lines at the germination stage can significantly reduce the time and cost of dryland wheat breeding programs for developing drought-resistant varieties. Identifying the stress tolerance of unreleased lines through laboratory simulation of drought stress, including novel methods to aid in the selection of drought-tolerant varieties in the final stages, is an innovative approach. Moreover, the germination stage is crucial for plant establishment. This stage is critical for plant growth and development and, if tolerant lines are available, can significantly impact bread wheat yield.
Materials and Methods: This experiment was conducted to investigate the germination characteristics of 11 advanced dryland bread wheat lines under four osmotic potential levels (-2, -4, -6, and -8 bars) induced by polyethylene glycol 6000, along with a control (for a total of five levels), under laboratory (controlled) conditions at Persian Gulf University. The investigation was performed as a factorial experiment under a completely randomized design (CRD) with three replications. Fourteen traits were measured in this experiment, including germination percentage, germination rate (number of seedling per day), fresh and dry weight (gr), radicle and plumule length(cm), growth rates of radicles and plumules, vigor indices I and II, and allometric coefficient.
Results: The average of all traits decreased with increasing stress levels. Results of ANOVA showed a significant interaction at the 1% level between lines and drought stress treatments. Therefore, physical slicing analysis was conducted at each stress level to compare the lines. The response of the lines to different traits was of an ordinal interaction type. As drought stress levels increased, the germina