Agronomic Bio-Fortification of Wheat to Combat Zinc Deficiency in Developing Countries
Muhammad Umair Hassan1, Muhammad Aamer1, Muhammad Nawaz2, Abdul Rehman3, Talha Aslam3, Ubaid Afzal4, Bilal Ahmad Shahzad3, Muhammad Ahsin Ayub5, Faryal Ahmed1, Ma Qiaoying1, Su Qitao1 and Huang Guoqin1*
Zinc (Zn) deficiency is well reported problem around the globe causing severe reduction in crop yield and quality. The intake of inadequate foods low in Zn is the major cause of Zn deficiency in humans, especially in developing countries. The deficiency of Zn causes many irregularties in both plants and humans. The Zn deficiency considerably reduced the plant growth, tillers production, chlorophyll synthesis, and crop yield. Moreover, in the case of humans’ Zn deficiency causes blindness, lower intelligence quotient (IQ) levels, weaker immune system, and impaired physical and mental development. Wheat crop play a chief role in daily food requirement and calories need in developing countries, however, inherently wheat has lower Zn contents. Moreover, soil Zn deficiency further increasing the problem of low Zn contents in wheat grain. Thus, the finest way to combat the Zn deficiency is to produce the grains of wheat having desirable Zn contents at farmer’s field. The breeding and agronomic (fertilizer application) bio-fortification approaches are important ones to increase Zn concentration in wheat grains up to desirable levels. The genetic techniques are costly, and sustainable, however, they are long term and requires large breeding activities and resources. Conversely, agronomic techniques appear to be short term, quick and economic solution to increase the Zn contents to meet human needs. The application of Zn as foliar sprays, seed priming, soil application and soil+foliar application effectively enhanced Zn uptake and grain Zn contents. Zn fertilization also maintains desirable Zn availability in soil solution and maintains the Zn pools in plant tissues during later stages thus resulting in an increase in Zn accumulation in wheat grains. Therefore, in this review, we discussed roles of Zn in plants and humans and possible strategies to combat Zn deficiency in humans. Additionally, challenges for agronomic and breeding strategies and possible benefits of both these strategies also discussed in this review.