Genetic enhancement of grain iron and zinc content in pearl millet

Introduction Pearl millet [Pennisetum glaucum (L.) R. Br.] is a highly nutritious warm season cereal. In a major initiative to further improve its nutritive value, a partnership based research has been under way at the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) to eventually develop high-yielding hybrids with higher levels of iron (Fe) and zinc (Zn) contents. Objective We investigated some of the factors that can enhance breeding efficiency for these micronutrients. Methods Grain samples from various trials were harvested and analyzed using inductively coupled plasma optical emission spectroscopy, near-infrared reflectance spectrometry and energy-dispersive X-ray fluorescence (EDXRF) screening techniques. Results Large variability for and high levels of both Fe and Zn content were observed in breeding lines and populations (>80 ppm Fe and >60 ppm Zn). The Fe and Zn contents were positively and highly significantly correlated (r = 0.49 to 0.71). There were negative correlations (r = 0.39 to 0.58) between these micronutrients and grain yield, though significant only in the case of Fe content and in only three of the six trials. These micronutrients were not correlated with seed size and time to flower. Both Fe and Zn content were largely under additive genetic control with the predictability ratio of 0.91. Conclusion These results showed that effective selection for both Fe and Zn content is possible without compromising on grain yield and seed size, and the rapid and cost-effective EDXRF screening technique can accelerate the breeding efficiency. The additive gene action for these micronutrients would require their incorporation in both parental lines of the hybrids.