To determine the effects of irrigation on the phytate and mineral contents of the grain and to estimatethe magnitude of genotype-environment interaction, eight Iranian and two foreign wheat (Triticum aestivum L.) varieties were grown under dryland and irrigated conditions for 2 years. Grain yield, phytate P (PP), total P (TP), and PP as percent of TP were reduced while plant height, nonphytate P (NPP), and Ca were increased under dryland conditions. Genotypic variances were low while environmental variances comprised high proportions of total variability in the Iranian wheats. The genotype-environment interaction variance was low for plant height, Fe, TP, and yield and high for Mg and Zn. © 1979, American Chemical Society. All rights reserved.