Energy-Dispersive X-ray Fluorescence Spectrometry for Cost-Effective and Rapid Screening of Pearl Millet Germplasm and Breeding Lines for Grain Iron and Zinc Density

Comparison of energy-dispersive X-ray fluorescence (XRF) and inductively coupled plasma-optical emission spectroscopy (ICP) for iron (Fe) and zinc (Zn) densities in pearl millet grain samples from 11 trials showed significant differences between these two methods for both micronutrients. XRF values were more often higher than the ICP values for both micronutrients, but the differences were significant in only 15-38% genotypes for Fe and in 7-25% genotypes for Zn across the trials. In 82% genotypes the differences between these two methods were <= 6 mg kg(-1) for Fe; and in 88% genotypes, the differences were <= 4 mg kg(-1) for Zn. There were highly significant and high positive correlations between ICP and XRF for both micronutrients. Selection of genotypes above the XRF trial mean for Fe/Zn included at least 30% top-ranking genotypes based on ICP. Therefore, XRF can be used for cost-effective and rapid screening of a large number of grain samples in pearl millet biofortification programs.