Genotypes, epidemiological variables and fungicides application associated with wheat leaf rust development and grain...

Area of Science:

• Plant Pathology
• Agronomy
• Environmental Science

Background:

• Wheat leaf rust poses a significant threat to global food security, causing substantial yield losses.
• Understanding the epidemiological factors influencing leaf rust development is crucial for effective disease management strategies.
• Environmental conditions play a pivotal role in the progression of wheat leaf rust severity.

Purpose of the Study:

• To evaluate the response of diverse wheat genotypes to leaf rust severity under varying environmental conditions.
• To establish correlations between epidemiological variables and leaf rust development.
• To assess the efficacy of different fungicide applications in mitigating yield losses.

Main Methods:

• Field experiments were conducted over two crop seasons (2021-2022 and 2022-2023) at the Plant Pathology Hafizabad Research Station.
• Leaf rust severity was assessed, and its correlation with environmental factors (temperature, humidity, rainfall, wind speed) was analyzed.
• A predictive disease model was developed and validated using coefficient of determination (R² = 0.69) and RMSE.
• Fungicide efficacy was evaluated through single and multiple applications at critical growth stages (Zadok's scale 3, 4.3, 5.4).

Main Results:

• Significant correlations were found between leaf rust severity and maximum temperature, maximum relative humidity, rainfall, and wind speed.
• Minimum temperature and minimum relative humidity showed a negative association with disease development.
• The predictive model explained 48-69% of the variability in leaf rust severity, demonstrating acceptable predictive accuracy.
• Prothioconazole, applied once or twice, was the most effective fungicide, significantly reducing disease severity and increasing grain yield and revenue.
• Other tested fungicides, including propiconazole, tebuconazole + trifloxystrobin, tebuconazole, bixafen + tebuconazole, and propiconazole (Tilt), also showed varying degrees of effectiveness.

Conclusions:

• Integrating genotype resistance and weather-based prediction models is recommended for enhancing wheat leaf rust management.
• Fungicide application timing and choice, particularly prothioconazole, are critical for minimizing yield losses and maximizing economic returns.
• The findings contribute to developing sustainable disease control strategies for wheat cultivation.