Terminal drought and a d2 dwarfing gene affecting grain iron and zinc density in pearl millet

Abstract

Pearl millet, predominantly a rainfed dryland crop, often encounters terminal drought in crop season. Grain hybrids grown in India are of medium to tall height, and majority of them are based on d2 dwarf seed-parents. Eight pairs of tall and d2 dwarf isogenic-lines, developed from two diverse composites, were evaluated under irrigated control and imposed terminal drought for two-years to examine the effect of d2 dwarfing gene and terminal drought on grain iron (Fe) and zinc (Zn) density. In general, terminal drought had a significant effect on increasing the Fe and Zn density, the d2 dwarfing gene or the linked gene block significantly decreased both micronutrients, with the magnitude of increase or decrease, respectively, dependent on the environment and genetic background of the isolines. Terminal drought has severe adverse impact on grain yield, but grains produced from such environments are likely to be more nutritious with respect to Fe and Zn density. The d2 dwarf hybrids are likely to be less nutritious than non-d2 hybrids with respect to Fe and Zn density. Whether the d2 dwarf seed parents with reduced Fe and Zn density presumably may adversely affect grain yield and micronutrient levels of even non-d2 hybrids developed on them, and this aspect merits further investigation.