Wheat Genotype Improvement Evolution of Selection Strategies for Stress and Nutrition

Abstract

Wheat is one of the most important cereal crops for global food and nutritional security, but its productivity and grain quality are increasingly affected by abiotic stresses and micronutrient deficiencies. This review summarises the evolution of selection strategies used for wheat genotype improvement, with emphasis on stress tolerance and nutritional enhancement. Conventional breeding methods, including phenotypic selection, pedigree breeding, backcrossing and mutation breeding, have contributed substantially to the development of high-yielding and disease-resistant wheat cultivars. However, these approaches are often time-consuming and less efficient for complex traits such as drought tolerance, heat tolerance, salinity tolerance, nutrient-use efficiency, grain protein content and micronutrient accumulation. Modern breeding strategies, including marker-assisted selection, quantitative trait loci mapping, genome-wide association studies, genomic selection, high-throughput phenotyping and genome editing, have improved the precision and efficiency of wheat improvement programmes. These approaches support the identification and transfer of genes and genomic regions associated with stress adaptation, yield stability and nutritional quality. Biofortification-oriented breeding has also gained importance for improving grain iron, zinc and protein content, particularly in regions where wheat is a major dietary component. Despite these advances, wheat improvement remains constrained by genotype-by-environment interaction, narrow genetic diversity, phenotyping limitations, infrastructure gaps and possible trade-offs among yield, stress tolerance and nutritional quality. Integrated use of conventional breeding, molecular tools, physiological screening and genomic technologies offers a practical pathway for developing wheat genotypes with improved resilience and nutritional value under changing environmental conditions.