Article ID: 26055
Heat stress during grain filling reduces wheat thousand-kernel weight (TKW) and grain mineral levels, resulting in lower yield and nutritional quality. Improving both traits is challenging due to a trade-off between larger grains and higher mineral concentrations under stress. In this study, wheat multiple-derivative lines carrying wild emmer introgression segments were evaluated under optimal and two heat-stressed field environments to identify candidate lines and genetic loci associated with TKW and mineral resilience. Heat stress decreased TKW and mineral levels; however, some lines maintained both, indicating potential to overcome trade-offs. Genome-wide studies identified marker-trait associations and loci on chromosome 7A linked to stress tolerance indices for TKW and to Fe and Zn levels under heat stress, as well as other loci on chromosomes 1A, 3A, 6A, 7A, 5B, and 6B associated with maintaining Fe, Zn, Mn, and Mg levels. Candidate genes involved in mineral transport, remobilization, and stress response were identified. Wild germplasm offers alleles that enhance wheat's tolerance to heat stress and its nutritional value. These findings support breeding heat-tolerant, nutrient-rich wheat varieties adapted to climate change.
