Sorghum: Annotated Bibliography

Introduction

Dietary deficiency of micronutrients, leading to hidden hunger, has been recognized by the World Health Organization as a serious human health problem worldwide, especially in populations having limited access to fruits, vegetables and livestock products. Three micronutrients iron, zinc and provitamin A are widely deficient, especially among low economic group population in developing countries. Micronutrient malnutrition arising from Zn and Fe deficiencies alone affects over 3 billion people around the world (http://www.unscn.org). Nearly 500,000 children (<5 years of age) die annually because of Zn and Fe deficiencies (Black et al., 2008). Among the 26 major risk factors of the global burden of disease estimates, iron deficiency

Its nutritional richness and stress resistance makes it an important crop choice in Africa and Asia. Sorghum is the second cheapest source of energy and micronutrients (after pearl millet); and a vast majority of the population in Africa and central India depend on sorghum for their dietary energy and micronutrient requirement (Rao et al., 2006). Sorghum stover is the major source of dry fodder for urban and peri-urban dairy production in India (Tesfaye, 1998). In terms of nutrient uptake, sorghum account for about 35% of total intake of calories, protein, Fe and Zn in the dominant production/consumption regions of India (Rao et al., 2006). Biofortification of sorghum by increasing mineral micronutrients (especially iron and zinc) in grains is widespread interest (Pfeiffer and McClafferty 2007; Zhao, 2008). Breeding for grain Fe and Zn enrichment requires sufficient genetic variability for grain micronutrient in the available germplasm as well as the information on genetic control of grain micronutrient content in the seed. Also reported significant positive association between two traits (Reddy et al., 2010) indicates the common genomic region or genes or biochemical pathway involved in expression of the trait. Hence the knowledge of phenotypic association between the traits gives basic idea for simultaneous improvement of the trait. Apart from this, understanding the environment is considered important in breeding for traits that depends on many factors (Campbell and Lafever, 1980; Ghaderi et al., 1980; Fox and Rosielle, 1982; Yau et al., 1991, Joshi et al., 2007). Proper characterizing and understanding of locations is very important for screening breeding lines of greater concentration of zinc and iron in the grain (Ortiz- Monasterio et al., 2007). The soil type and soil nutrient status vary greatly in central India where sorghum cultivation is concentrated, under such conditions, genotype × environment (G