Mixed linear models for the genetic inheritance of grain zinc and iron content, agronomic and biochemical traits in bread wheat under salinity stress

Wheat is a staple food crop that acts as a primary source of dietary calories, protein and most of the bioavailable micronutrients such as iron (Fe) and zinc (Zn) for the world's population. Understanding genetic control of micronutrients uptake is necessary for the development of bio-fortified wheat genotypes. Salinity as an abiotic stress could affect the nature of this process. To study the inheritance of Zn and Fe efficiency under non-saline and saline conditions, two Iranian facultative wheat varieties, Navid (salt-sensitive, Fe and Zn-deficient) and Roshan (salt-tolerant, Fe and Zn-efficient) were crossed to generate six basic generations. The six generations were evaluated for grain Zn and Fe content, agronomic and biochemical traits under non-saline and saline conditions and generation mean analysis was performed using mixed linear models. The results revealed a greater contribution of non-additive gene actions in controlling of the traits compared to additive gene actions. Additive effects were negative and significant for all the traits under non-saline and saline conditions, except for 100 seed weight (100-SW) at non-saline condition, malondialdehyde (MDA) in 100 mM NaCl, electric leakage (EL) and leaf Na(+ )concentration (LeaNa(+)C) under all salinity treatments. Additive gene actions had high contribution in grain Zn and Fe content, while for the rest of the traits both fixable and non-fixable genetic effects were important. A duplicate dominant type of epistasis was involved in the inheritance of all the traits. Broad-sense heritability for most traits under non-saline and saline conditions were high (> 0.8), whereas the narrow-sense heritability values for most of the studied traits were low to moderate. Therefore, the Zn and Fe efficiency indices could be used to select Zn/Fe-efficient wheat genotypes among segregating populations.