Fatemeh Vafaee, Hamidreza Nooryazdan, Rahmatolah Karimizadeh,
Volume 11, Issue 1 ((Spring and Summer) 2024)
Abstract
Extended 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 is among novel methods to aid in selecting drought-tolerant varieties in the final stages. Moreover, the germination stage is crucial for plant establishment. This stage is critical for plant growth and development and can significantly impact bread wheat yield in case tolerant lines are available.
Materials and Methods: This experiment was conducted to investigate the germination characteristics of 11 advanced dryland bread wheat lines at 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 in a completely randomized design (CRD) with three replications. Traits in this experiment including germination percentage, germination rate, growth rates of radicles and plumules, dry weight and length of radicle and plumule, seed vigor indices I and II, seedling length, and allometric coefficient were measured.
Results: The mean of all traits decreased with increasing stress levels. Results of ANOVA showed a significant interaction at the 1% level between the 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, germination percentage and rate, radicle and plumule growth rates, and seedling length decreased. Overall, lines 3 and 4 exhibited the highest germination percentage (58.86) and rate (3.60 seeds per day), as well as radicle (0.85 cm per day) and plumule rates (0.70 cm per day), and radicle (8.83 cm) and seedling (7.12 cm) length.
Conclusions: The response of the lines to different osmotic stress levels varied in terms of various traits. Based on the traits evaluated, lines 3 and 4 exhibited superior drought stress tolerance. These lines can be utilized in future breeding programs.
Highlights:
- Evaluating and screening wheat breeding lines for drought tolerance was performed by simulating stress conditions in the laboratory and comparing morphological traits in early plant growth stages.
- The response of the lines to similar levels of drought stress was heterogeneous, and physical slicing analysis based on each stress level revealed an ordinal interaction between stress and line levels.
