Agricultural strategies in fight against micronutrient malnutrition

Almost 2 billion people are under risk of micronutrient deficiencies due to low dietary intake of micronutrients, mainly in developing world. Iron (Fe), zinc (Zn) and iodine (I) deficiencies represent major micronutrient deficiencies globally. Diverse of health complications are known to be associated with deficiency of micronutrients including alterations in brain development and function, impairments in immune system and reductions in physical development. Very high proportion of cereal-based foods with low concentration Zn, Fe and iodine in the diet is suggested to be major reason of the micronutrient malnutrition in developing countries. Compared to animal-based foods and legumes, cereals are inherently very low in micronutrients. Today, increasing grain concentrations of the concerned micronutrients is an important global humanitarian challenge. Several agricultural strategies are used to improve grain micronutrients. Conventional plant breeding, genetic engineering and agronomic approaches (e.g., soil and/or foliar application of micronutrient fertilizers) are known to be major approaches to the problem. It important to highlight that plant breeding and fertilizer strategy strategies are not separate solutions to micronutrient malnutrition problem. Both strategies have synergistic and additive effects on increasing grain micronutrients. Published reports indicate thatfoliar application of micronutrients is highly effective in improving grain Zn, iodine and selenium. Under certain situations, also grain Fe concentrations can be improved by foliar spray of Fe fertilizers. Field experiments conducted in different countries under the Harvest Zinc project (www.harvestzinc.org) showed that foliar spray of micronutrients results in particular increases in concentrations of micronutrients both in whole grain and also in endosperm part. Irrespective of the strategies used (conventional breeding or transgenic technologies), maintenance of high pool and availability of Zn in growth medium or in vegetative tissue during seed filling period is absolutely required to achieve desirable concentrations of Zn in grains for human nutrition. Transgenic lines showing several fold increases in seed micronutrient concentrations under controlled and well-maintained growth conditions are unable to express same genetic capacity when they are grown under real world conditions. This paper will present new results and ideas about the role of fertilizer strategy in improving dietary intake Zn, Fe and iodine in an effective way.

کلیدواژه ها:

Micronutrients ، Fertlizers ، Genetic capapcity