**2. Wheat**

Wheat, grown in many parts of the world, is a major contributor to food security in that it is a staple food in other countries [1]. It has three main grain compartments such as the bran, endosperm and the germ. The wheat grain as a whole houses a series of nutritional health beneficial components ranging from macronutrients, micronutrients, vitamins, phenolic compounds and other components at different levels across various grain compartments [2]. The wheat grain is also a major contributor to the daily dietary intake required by individuals due to its regular consumption in various forms. Thus, regular consumption of essential nutrients at adequate levels could largely contribute to the reduction of nutrient deficiency-related ailments such as anaemia, growth and development problems, cardiovascular diseases, cancer, diabetes, neurological disorders, etc. [7].

Intriguingly, the endosperm region is the most edible part of the grain reported to contain less contents of Fe and Zn than the outer layers that are removed upon milling [18, 34]. Several efforts to establish the biofortification of wheat have been undertaken and some major challenges have been experienced. Little or no progress has been made to characterize the key biological process involved in the accumulation and bioavailability enhancement of Fe, Zn, vitamins and phenolic acids in this grain compartment [14].

Wheat has a complex genome and the complete genome sequence is not available yet. This makes it challenging to identify and understand the function of many genes in wheat, thereby making it difficult to characterize and manipulate complex traits of interest for the development of improved varieties. Further characterization of some traits is still needed for a continued contribution to better understand various gene networks/pathways and their role within the wheat genome to allow rapid development of improved cultivars with desirable traits of interest for a continued contribution to food and nutrition security. There are various wheat genetic resources ranging from landraces to wild relatives that may carry various genes of interest due to their genetic diversity [1, 35, 36]. Genetic resources have been utilized for crop improvement efforts in cases where information regarding a complex trait is not readily known, the information may then be inferred from closely related species with known biology [1].
