Wheat yield has minimal effect on grain mineral density

Authors: Adams, Curtis; GRAEBNER, RYAN - Oregon State University; MARSHALL, JULIET - University Of Idaho; NEELY, CLARK - Washington State University; LONG, DANIEL - Collaborator; Reardon, Catherine; Rogers, Christopher

Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 9/29/2024
Publication Date: 11/12/2024
Citation: Adams, C.B., Graebner, R.C., Marshall, J., Neely, C., Long, D.S., Reardon, C.L., Rogers, C.W. 2024. Wheat yield has minimal effect on grain mineral density. ASA-CSSA-SSSA Annual Meeting Abstracts. https://scisoc.confex.com/scisoc/2024am/meetingapp.cgi/Paper/156331.

Interpretive Summary: There are human populations worldwide that lack diversified diets and rely on staple foods, like wheat, as primary sources of mineral nutrients. This includes minerals such as Zn, Fe, and K. Cereal grains are inherently poor in minerals, however. As a result, efforts have been made to enhance the mineral density of wheat through plant breeding and crop management, though there has been concern that mineral concentration will decrease if yield increases. This concern is largely based on scientific studies that have shown higher grain mineral densities in ancestral or historic wheat compared to modern varieties, but there is not a clear understanding on how yield might affect mineral density if only modern wheat is considered. In a large investigation of this issue, we found that there was no effect of yield on density of any tested mineral in grain when factors such as production environment and test weight were properly controlled. Production environment had the greatest impact on grain mineral density, followed by wheat genotype and grain test weight. The results suggest that breeding for increased grain mineral density will be most successful for Zn, P, and Mg. In summary, this analysis provides evidence that the impact of yield on grain mineral density among modern wheat germplasm is small and insignificant. In the quest to improve the mineral nutrient value of wheat through plant breeding, crop management, and other approaches, yield should be considered secondarily to much more significant factors like production environment, wheat genotype, and even test weight.

Technical Abstract: In the quest to increase grain mineral density of wheat (one aspect of nutritional value), there has been concern of a mineral-yield tradeoff. This concern primarily stems from results showing higher grain mineral density in historic and ancestral wheats compared to modern cultivars, which differ greatly in yield, but also in many other genetic traits (e.g., tall vs. semi-dwarf). Thus, our central objective in this research was to better understand if increased yield decreases grain mineral density (P, K, Mg, Ca, Fe, Mn, Zn, and Cu) among modern wheat cultivars. We accomplished this by assembling a genetically and environmentally diverse grain mineral dataset and analyzing it from multiple angles. Controlling for production environment and grain test weight, our results showed no significant effect of yield on concentration of any mineral in grain. Mineral density was most affected by production environment, which contributed between 50% and 90% of variation in the data, depending on mineral. Wheat cultivars, including cultivar-by-environment interactions, and grain test weight also commonly impacted grain mineral density. Among all minerals analyzed, results showed relatively high genotypic variation and heritability for grain Zn, P, and Mg, indicating that these minerals may be most effectively increased through plant breeding selection. Additional analysis specific to grain Zn showed that, across diverse production environments and yield levels, individual wheat cultivars tended to have consistent grain Zn density relative to the average. Thus, breeding for high Zn / high yield cultivars is possible. In conclusion, our analysis indicates that yield has minimal impact on grain mineral density among modern cultivars. As higher yields are sought to feed a growing population, there should be little concern that this endeavor is decreasing the mineral nutrient value of wheat. Variation exists among wheat germplasm and production environments to select and manage for enhanced mineral nutrition.