Email: v.guwela@gmail.com julieking@nottingham.ac.uk

Micronutrient deficiencies (MNDs) particularly zinc (Zn) and iron (Fe) remain widespread in sub-Saharan Africa (SSA) due to low dietary intake. Wheat is an important source of energy globally, although cultivated wheat is inherently low in grain micronutrient concentrations.

Hexaploid wheat/Am. muticum and wheat/T. urartu BC1F3 introgression lines, developed by crossing three Malawian wheat varieties (Kenya nyati, Nduna and Kadzibonga) with DH-348 (wheat/Am. muticum) and DH-254 (wheat/T. urartu), were phenotyped for grain Zn and Fe, and associated agronomic traits in Zn-deficient soils in Malawi.

Whole genome sequencing, Chromosome specific KASP genotyping and Genomic in-situ hybridization revealed that some introgression lines carried either a combination of the 4T and 7T Am. muticum introgressions on wheat chromosome 4D and 7A respectively, or a 4T and 7T segment only. Introgression lines with the T. urartu segments had the 5Au segment recombined with wheat chromosome 5A.

Field phenotyping results showed that 98% (47) of the BC1F3 introgression lines had higher Zn above the checks Paragon, Chinese Spring, Kadzibonga, Kenya Nyati and Nduna. 23% (11) of the introgression lines showed a combination of high yields and an increase in grain Zn by 16-30 mg kg -1 above Nduna and Kadzibonga, and 11-25 mg kg -1 above Kenya nyati, Paragon and Chinese Spring.

Among the 23%, 64% (7) also showed 8-12 mg kg -1 improvement in grain Fe compared to Nduna and Kenya nyati. Grain Zn concentrations showed a significant positive correlation with grain Fe, whilst grain Zn and Fe negatively and significantly correlated with TKW and grain yield.

Use of wheat wild relatives in breeding programs has potential to increase mineral nutrient density in wheat grains.