Effects of foliar fungicide on yield, micronutrients, and cadmium in grains from historical and modern Hard winter wheat genotypes

Authors: MOTTA-ROMERO, HOLLMAN - University Of Nebraska; FERDINAND, NIYONGIRA - University Of Nebraska; Boehm Jr, Jeffrey; ROSE, DEVIN - University Of Nebraska

Submitted to: PLOS ONE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/18/2021
Publication Date: 3/4/2021
Citation: Motta-Romero, H., Ferdinand, N., Boehm Jr, J.D., Rose, D.J. 2021. Effects of foliar fungicide on yield, micronutrients, and cadmium in grains from historical and modern Hard winter wheat genotypes. PLoS ONE. 16(3):e0247809. https://doi.org/10.1371/journal.pone.0247809.
DOI: https://doi.org/10.1371/journal.pone.0247809

Interpretive Summary: Plant breeding has increased wheat yield to feed the constantly growing global population and to face the challenges posed by climate change. Nevertheless, increased grain yield might negatively affect the nutritional quality of wheat through dilution. In addition to plant breeding, agronomic practices like fungicide application tend to increase yield, but could affect wheat nutritional quality. Our objectives were to estimate historical trends for yield, protein, grain mineral elements, and the anti-nutritional factors, phytate and cadmium, using 20 historic wheat lines adapted to the Great Plains and grown with or without fungicides. Grain yield increased steadily since 1870 but the concentration of essential nutrients such as protein, iron, and zinc decreased. Unexpectedly, cadmium concentration increased and represents a possible threat to public health. Fungicide application reduced grain cadmium concentration in all cultivars indicating fungicide application could be a useful agronomic practice for farmers to increase yield and economic returns while reducing grain cadmium concentrations.

Technical Abstract: Plant breeding and disease management practices have increased the grain yield of hard winter wheat (Triticum aestivum L.) adapted to the Great Plains of the United States during the last century. However, the effect of genetic gains for seed yield and the application of fungicide on the micronutrient and cadmium (Cd) concentration in wheat grains is still unclear. The objectives of this study were to evaluate the effects of fungicide application on the productivity and nutritional quality of wheat by comparing landraces and cultivars representing over 140 years of plant breeding efforts. Field experiments were conducted over two crop years (2017 and 2018) with twenty hard winter wheat genotypes released between 1870 and 2013 in the presence or absence of fungicide application. For each growing season, the treatments were arranged in a split-plot design with the fungicide levels (treated and untreated) as the whole plot treatments and the genotypes as split-plot treatments in triplicate. The effects on seed yield, grain protein concentration (GPC), micronutrients, phytic acid, and Cd in grains were measured. While the yield of wheat was found to increase at annualized rates of 16.5 and 8.8 kg ha-1 yr-1 in the presence and absence of fungicide (P < 0.001), respectively, GPC (-120 and -140 mg kg-1 yr-1, P < 0.001), Fe (-28 and -35 µg kg-1 yr-1, P < 0.05), and Zn (-37 and -41 µg kg-1 yr-1, P < 0.001) significantly decreased during the period studied. In contrast to the other mineral elements, grain Cd significantly increased over time (0.22 and 0.48 µg kg-1 yr-1, P < 0.01). The results from this study are of great concern, as many mineral elements essential for human nutrition have decreased over time while the toxic heavy metal, Cd, has increased, indicating modern wheats are becoming a better vector of dietary Cd.