Nitrogen use efficiency in bread wheat: Genetic variation and prospects for improvement

Area of Science:

• Agricultural Science
• Plant Breeding
• Agronomy

Background:

• Nitrogen (N) is a critical macronutrient for wheat yield, often limiting in low-fertility soils.
• Small and marginal farmers in South Asia face economic constraints in affording sufficient nitrogen fertilizers.
• Developing nitrogen-efficient (NUE) wheat genotypes is essential for sustainable agriculture in these regions.

Purpose of the Study:

• To evaluate diverse wheat genotypes for nitrogen use efficiency (NUE) under varying nitrogen levels.
• To identify wheat lines exhibiting high yield performance and NUE in nitrogen-deficient environments.
• To provide data supporting breeding programs for developing N-efficient wheat varieties for marginal agro-ecologies.

Main Methods:

• Fifty diverse wheat genotypes were assessed for 24 agro-morphological, physiological, and NUE traits.
• Evaluation was conducted in an N-depleted field under two nitrogen application rates: 50% (N50) and 100% (N100) of the recommended dose.
• Statistical analysis (ANOVA) was employed to determine genetic variation and trait correlations.

Main Results:

• Significant genetic variation was observed among genotypes for all studied traits.
• Yield reduction of approximately 11.36% occurred under reduced nitrogen levels.
• Specific genotypes (UASBW13356, UASBW13358, UASBW13354, UASBW13357, KRL1-4) demonstrated N-insensitivity and genotypic plasticity, maintaining yield under low N.

Conclusions:

• Significant correlations between NUE traits and yield components highlight the importance of nitrogen remobilization for grain yield.
• Identified N-insensitive genotypes possess inherent plasticity and can be utilized as parents in breeding for enhanced NUE.
• The findings support breeding efforts for NUE, benefiting small and marginal farmers in South Asia by reducing reliance on costly nitrogen fertilizers.