No abstract

The combined application of nitrogen (N) and zinc (Zn) appears to be a promising agronomic strategy for the biofortification with Zn. To evaluate such efficiency, a field experiment was conducted in south-eastern Portugal under Zn-deficient soil. Four advanced breeding lines and two commercial varieties of bread wheat (Triticum aestivum L.) were fertilized with five treatments: i) control, ii) two foliar Zn applications, iii) one foliar Zn+N application, iv) soil and two foliar Zn applications, and v) soil and one foliar Zn+N application. Grain Zn content varied greatly across treatments and INIAV-1 and the commercial varieties were the most interesting cultivars in all the treatments. Grain Zn concentrations higher than the target level of 38 mg Zn kg -1 were obtained only when two foliar Zn applications were applied, alone or in combination with soil Zn applications, and grain Zn bioavailability also was more adequate (phytate:Zn ratios similar to 15). Soil Zn application resulted in grain yield increases between 7-10%, which virtually offset the extra application cost. The combined soil and two foliar treatment could be a good option for biofortifying bread wheat under Zn-deficient soils.

About 3 billion people may suffer from micronutrient deficiency such as Ca, Fe, Mg or Zn, caused not only by a mineral deficiency in staple food but also by a high content of phytates which bind those minerals and inhibit their absorption. With the aim of evaluating the potential of new cultivars of bread‐making wheat to accumulate those minerals and low phytates, nine advanced breeding lines from an ongoing Portuguese breeding program were studied during 2 years in a field experiment. A wide genetic variability was found between the studied genotypes in all the parameters studied, especially grain yield (ranging on average between 2,027 and 3,209 kg/ha) and grain Mg and Zn concentrations (ranging on average between 1,070 and 1,336 mg/kg, and 23.4 and 30.7 mg/kg, respectively). In global terms, the cultivars with best performance, and therefore, the most potentially suitable to be used in a breeding program, were the Cultivars 3 and 4. However, such a potential varied depending on the analysed trait, and it was clearly influenced by the climatic conditions. The consumption of 100 g of Cultivar‐4 produced under the most favourable conditions might provide a 5.2% of Ca, 26.4% of Fe, 38.9% of Mg and 31.9% of Zn of the recommended daily intakes, with a very good bioavailability for Fe and Ca, but low for Mg and Zn.