Bread wheat genetic variation for grain’s protein, iron and zinc concentrations as uptake by their genetic ability

• The aim of this study was to screen 80 genotypes of bread wheat representing the most commercial wheat cultivars released or introduced during 70 years ago and elite lines cultivated in Iran, under normal and terminal drought stress conditions (two environments).
• A wide range of genetic variation was identified among tested wheat genotypes for studied traits particularly iron, zinc and protein concentrations as well as grain yield.
• We observed negative correlations between the grain yield and grain protein, iron and zinc concentrations which were also confirmed by GGE-Biplot analyses.
• We concluded that the older genotypes have highest grain protein, iron and zinc concentrations, while their grain yields were at the lower levels. We draw trends between these traits and date of cultivar release over 70 years. The interesting finding is breeders’ attention to enhancing grain production caused to neglect the quality of wheat production specially protein, iron and zinc concentrations during last 70 years. In this study, the effect of drought stress on the different traits was identified.

Genetic diversity among 80 irrigated bread wheat genotypes was studied for their grain’s protein, iron and zinc concentrations as well as agronomic traits. The trend of these traits over the 70 years of cultivar releasing was demonstrated. The experiment was conducted as a RCBD with three replicates under normal and terminal drought stress conditions in Kermanshah, Iran during 2011–2012 cropping season. The results of combined ANOVA revealed high significant genotypic differences for all traits, except grain iron and zinc yield. Terminal drought stress reduced all studied traits except grain iron concentration which it increased by 14.10%. The maximum effect of drought stress was on grain zinc yield, grain yield and thousand grain weight as much as 26.65, 23.48 and 18% reduction, respectively. In both conditions, there were negative correlations among grain yield and grain iron, zinc and protein concentrations. Moreover, it was found that grain yield was increased with a small improvement during 70 years while protein, iron and zinc concentrations were decreased over the years. A wide range of genetic diversity in micronutrients uptake, particularly iron and zinc within studied wheat genotypes was identified which suggesting that selection for improved micronutrients efficiency is possible. What was concluded from this study is breeders’ attention to enhancing grain production caused to neglect the quality of wheat production specially protein, iron and zinc concentrations during the last 70 years.