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Breeding wheat for improved nutritional quality: Insights from a winter wheat association mapping panel
Wheat is a major staple cereal in human diets that provides nutritionally important minerals. Because grain mineral concentrations tend to decrease as wheat yields increase, breeding for yield improvement may have reduced nutritional quality. The objectives of this study were to survey grain mineral concentration in Great Plains hard winter wheat to assess: 1) the heritable variation for grain mineral concentrations in the germplasm pool; 2) the effects of more than 50 years of wheat breeding on mineral concentrations; and 3) opportunities to exploit the underlying physiological relationship between grain protein concentration (GPC) and grain mineral concentration to improve nutritional quality. Grain mineral concentrations were measured in a panel of 299 winter wheat genotypes grown in 2012 and 2013 in Oklahoma and Nebraska. Significant genetic variation persists within contemporary germplasm: among 93 cultivars released since 2000, Zn concentration max:min ratios ranged from 1.5 - 2.3. Within the subset of cultivars released from 1960 to 2014, grain yield increased 0.58 to 1.25 % yr-1, and Zn concentration decreased 0.15 to 0.26% yr-1, relative to the reference cultivar, `Scout 66.' The positive interrelationship between GPC and grain Fe and Zn concentrations could be exploited in a yield-neutral breeding strategy that selects genotypes based on grain protein deviation. Cd concentrations exceeded international standards in some genotypes. We found highly repeatable differences in grain Cd among commercial cultivars across 11 Nebraska trials. Grain Cd concentration was predicted by concentration in above-ground plant tissues. Genome wide association scans using high density SNP markers identified associations of grain Cd with SNP markers on 5AL. Cd-associated SNP markers are in a homoeologous region to the Cdu1 locus on 5BL in durum wheat. Grain Zn concentration was not well predicted by plant concentration at anthesis, and SNP marker associations with Zn were weak and inconsistent across trials. Selection for reduced grain Cd concentration without decreased grain Zn concentration has high potential for success within Great Plains hard winter wheat.
Guttieri, Mary Joy, "Breeding wheat for improved nutritional quality: Insights from a winter wheat association mapping panel" (2014). ETD collection for University of Nebraska - Lincoln. AAI3643408.