Genetic Resources, International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Patancheru, India. *Corresponding author: h.upadhyaya@cgiar.org

Sorghum [Sorghum bicolor (L.) Moench], the 5th most important cereal after maize, rice, wheat, and barley in area, is mostly grown worldwide by the resource-limited farmers in the Semi-Arid Tropics (SAT). Africa and the Americas together contribute 75% (40.74 m t) of the total world sorghum production, while Asia 19.5% (10.59 m t). India and Nigeria are the largest producers, and each contribute ~13% of the world sorghum production (6.9 to 7.0 m t). The average productivity of sorghum varies from 0.28 t ha-1 in Niger to 4.4 t ha-1 in Argentina (Table 2-1; https://faostat. fao.org, accessed on April 15, 2013). Several factors contribute to such variability in sorghum productivity. Abiotic and biotic stresses, amongst others, contribute maximum to the variation in sorghum production and productivity. Drought, salinity and heat are the major abiotic stresses. The biotic stresses include diseases, pests and viruses. The major diseases affecting sorghum production include grain mold (caused by a complex of several fungal species), downy mildew (Peronosclerospora sorghi [Wetson and Uppal (Shaw)]), anthracnose [Colletotrichum graminicola (Ces.) GW Wilson], rust (Puccinia purpurea Cooke), leaf blight [Exserohilum turcicum (Pass.) KJ Leonard & EG Suggs], charcoal rot/stalk rot [Macrophomina phaseolina (Tassi) Goid], and several virus diseases, while amongst the pests, shoot fl y [Atherigona soccata (Rondani)], stem borer [Chilo partellus (swinhoe)] and [Sesamia inferens (Walker)], midge (Contarinia sorghicola Coq.), and head bug (Calocoris angustatus Leth) are the major pests of sorghum. These stresses often occur in combinations that cause substantial worldwide losses to sorghum production (House 1985; Sharma 1993; Kumar et al. 2011).