STATUS OF HYDROCYANIC ACID CONTENT OF SORGHUM IN RELATION TO IRRIGATION AND STORAGE TEMPERATURE

HARPREET KAUR OBEROI* AND MANINDER KAUR
Forages, Millets and Nutrition Section,
Department of Pant Breeding and Genetics,
Punjab Agricultural University,
Ludhiana-141004 (Punjab), India
*(e-mail : harpreetoberoi@pau.edu)
(Received : 09 November 2020; Accepted : 10 December 2020)

SUMMARY

Sorghum bicolor (L.) Moench produces the nitrogen-containing natural product dhurrin that provides chemical defence against herbivores and pathogens via the release of toxic hydrogen cyanide gas. Drought can increase dhurrin in shoot tissues to concentrations toxic to livestock. In the present study, plants were grown under two watering regimes and HCN concentrations were assessed in fodder sorghum under room (37 ºC) and freezing (-15 ºC) temperature conditions. Water limitation and storage temperature were found to be the most important determinants of dhurrin concentration in fodder sorghum. The hydrogen cyanide (HCN) production was more in the plants grown under drought conditions when compared with plants grown under irrigated conditions. HCN concentration was more, percent increase of 116-220% in irrigated crop and 88-400% in non-irrigated crop, when leaves were store under cold temperature as cold stress event was as effective as fine grinding in facilitating complete conversion of dhurrin to cyanide. Increased uptake of forage sorghum grown under irrigated conditions is required so that farmers are assured of cyanogen-safe fodder. From these studies, it can be concluded that sorghum crop cultivated especially under drought conditions should be strictly evaluated for HCN estimation before its use as fodder for livestock and should be dried after harvest for few hours at room temperature. The dried sorghum fodder is safer with respect to anti-nutrient HCN then freshly cut fodder sorghum (60 days after sowing).

Key words:HCN, fodder sorghum, irrigation, drought

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