Integrating yield-based drought tolerance indices with GT biplot, MGIDI and FAI-BLUP for selection of bread wheat genotypes under late drought

Late-season drought represents a major constraint to bread wheat productivity, while genotype selection based on individual drought indices remains challenging because different indices capture distinct, and often highly correlated, aspects of drought response. This study aimed to identify drought-adapted bread wheat genotypes using an integrated analytical framework combining yield-based drought tolerance and susceptibility indices, genotype-by-trait (GT) biplot analysis, and two complementary multi-trait selection approaches: the Multi-Trait Genotype–Ideotype Distance Index (MGIDI) and Factor Analysis and Ideotype-Design Best Linear Unbiased Prediction (FAI-BLUP). Sixty-four bread wheat genotypes were evaluated under well-watered and late-season drought conditions over two consecutive growing seasons, and twelve drought tolerance and susceptibility indices were calculated based on grain yield. Correlation and multivariate analyses revealed substantial redundancy among productivity-oriented indices, particularly STI, GMP, MP, and HM, whereas susceptibility-related indices represented a contrasting dimension of drought response. The GT biplot based on the combined dataset explained 98.88% of the total variation and clearly differentiated productivity, yield-maintenance, and drought-susceptibility dimensions. MGIDI identified G29, G43, and G12 as the genotypes closest to the predefined ideotype, followed by G38, G3, G5, G52, G40, G24, and G42. FAI-BLUP likewise ranked G29, G43, and G12 as the three highest-ranking genotypes. Six genotypes—G29, G43, G12, G5, G40, and G52—were consistently selected by both approaches, corresponding to a 60% overlap between the MGIDI and FAI-BLUP selections. The six genotypes jointly selected by MGIDI and FAI-BLUP are candidate materials for further evaluation. Their agreement describes concordance between analyses of the same yield-derived information and does not constitute independent validation of drought tolerance. The experiment was restricted to one location, two growing seasons, and late-season drought imposed from booting to physiological maturity. Multi-environment testing is required before stable superiority, or breeding utility can be established.