Cyanogenic Potential of Sorghum Species (fodder crops) grown in Tehsil Burewala, Punjab, Pakistan

Abstract

In this study cyanide levels and factors affecting cyanide levels in various sorghum species were determined. A total of 500 samples of various sorghumspecies were collected from the crop fields of different areas of Tehsil Burewala, Pakistan. They included 100 samples each of Sorghum bicolor, S. sudanese, Jumbo grass (S. bicolor x S. sudanese hybrid), S. halepense and maize. An estimation of cyanide levels in the samples was performed spectrophotometerically using the picrate kit method. A significant difference (P<0.05) was observed between CNֿ contents of Jumbo grass (211.7±9.086 mg/kg) and S. halepense (244.9±9.659 mg/kg). Jumbo grass and S. halepense have significantly higher (P<0.05) CNֿ concentrations than S . bicolor or S. sudanese but the CNֿ contents of S. halepense were significantly higher than Jumbo grass . Maize has significantly lower (P<0.05) values of CNֿ contents (6.6±0.529 mg/kg) than any of S. bicolor, S. sudanese, Jumbo grass or S. halepense. All species showed a gradual increase in CNֿ contents with increase in height of the plants. The CNֿ contents in leaves of all plants species were significantly higher (P<0.05) than CNֿ contents of stem. In conclusion Jumbo grass and S . halepense possess higher cyanogenic potential compared to S . bicolor or S . Sudanese, and cyanide content increases gradually with increasing height of plants up to 91-100 cm. At greater heights, CNֿ content gradually decreases in all plant species. In conclusion, the CNֿ content can vary among plant species and among varieties of the same species as well as during different growth stages.