Phenotyping for drought resistance in bread wheat using physiological and biochemical traits

Area of Science:

• Agricultural Science
• Plant Physiology
• Genetics

Background:

• Drought stress is a major constraint on global crop productivity, particularly for essential staples like bread wheat.
• Understanding the physiological and biochemical responses of wheat to drought is crucial for developing resilient varieties.

Purpose of the Study:

• To investigate the relationship between fifteen physio-biochemical traits (PBT) and grain yield under drought stress.
• To identify high-yielding bread wheat genotypes with enhanced stress tolerance capabilities using multivariate analysis and heatmapping.
• To explore the genetic basis of drought tolerance by comparing genotypic and phenotypic correlations.

Main Methods:

• A pot experiment was conducted using 120 diverse bread wheat genotypes under control and drought stress conditions.
• Multivariate analysis, including principal component analysis (PCA) and genotype by trait (GGT) biplot analysis, was employed.
• Heatmapping and stress tolerance index (STI) for grain yield were used to assess genotype performance and trait associations.

Main Results:

• Proline and sugar accumulation increased significantly under drought stress.
• Key traits like leaf relative water content (LRWC), leaf surface area (LSA), and canopy temperature depression (CTD) decreased under drought.
• Genotypic correlations (rg) were generally higher than phenotypic correlations (rp), indicating strong genetic control over trait relationships.
• PCA explained substantial variation (77.27% under control, 79.02% under drought) across the first seven components.

Conclusions:

• Physio-biochemical traits associated with the stress tolerance index (STI) for grain yield are critical for improving wheat productivity under drought.
• Selecting genotypes exhibiting favorable PBT performance under stress conditions can lead to more productive returns in a changing climate.
• The study highlights the importance of integrated approaches combining physiological measurements and genetic analyses for breeding drought-resilient wheat.