Characterizing sorghum genotypes for forage yield, hydrocyanic acid and sugar contents under arid climate conditions

Sorghum (Sorghum bicolor (L.) Moench) is a dual nature crop, which is used for food as well as fodder, depending on plant ideotype. Sorghum forage is important for ruminants, but a major constraint is the anti-nutritional factor dhurrin, a hydrocyanic acid (HCN) producing glucoside. There are several additional effects of dhurrin, which reduce the nutritional value of sorghum fodder for livestock. This two-year study was aimed to evaluate the variation among diverse sorghum varieties, specifically for HCN content, forage yield and stem sugar content (brix value) under arid climate in Pakistan. Nine sorghum varieties were used for this experiment: JS-2002, Chakwal sorghum, Lines CS-17, Super late, PAK SS-2, Johar, JS-263, Sargodha-2011 and YSS-98. Results reveal that Sargodha-2011 had superior morphological traits for fresh forage and dry biomass yield, and stem brix value, compared to other varieties. Higher HCN contents were recorded in Super late compared to other varieties. Significant negative correlation of HCN with yield showed that improvement in yield will reduce the HCN content of sorghum. In conclusion, sorghum variety SGD-11 was shown best performing for higher biomass yield and brix value, and lower HCN content compared to other tested varieties under arid climate of Thal, Pakistan.