Sorghum bicolor (L.) Moench is a multipurpose food crop which is ranked among the top five cereal crops in the world, and is used as a source of food, fodder, feed, and fuel. The genus Sorghum consists of 24 diverse species. Cultivated sorghum was derived from the wild progenitor S. bicolor subsp. verticilliflorum, which is commonly distributed in Africa. Archeological evidence has identified regions in Sudan, Ethiopia, and West Africa as centers of origin of sorghum, with evidence for more than one domestication event. The taxonomy of the genus is not fully resolved, with alternative classifications that should be resolved by further molecular analysis. Sorghum can withstand severe droughts which makes it suitable to grow in regions where other major crops cannot be grown. Wild relatives of many crops have played significant roles as genetic resources for crop improvement. Although there have been many studies of domesticated sorghum, few studies have reported on its wild relatives. In Sorghum, some species are widely distributed while others are very restricted. Of the 17 native sorghum species found in Australia, none have been cultivated. Isolation of these wild species from domesticated crops makes them a highly valuable system for studying the evolution of adaptive traits such as biotic and abiotic stress tolerance. The diversity of the genus Sorghum has probably arisen as a result of the extensive variability of the habitats over which they are distributed. The wild gene pool of sorghum may, therefore, harbor many useful genes for abiotic and biotic stress tolerance. While there are many examples of successful examples of introgression of novel alleles from the wild relatives of other species from Poaceae, such as rice, wheat, maize, and sugarcane, studies of introgression from wild sorghum are limited. An improved understanding of wild sorghums will better allow us to exploit this previously underutilized gene pool for the production of more resilient crops.

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Aim To fill knowledge gaps regarding the distributions, ecogeographic niches and conservation status of sorghum's wild relatives (Sorghum Moench). Location The study covered the potential native ranges of wild Sorghum taxa worldwide, including Australia, New Guinea, Asia, Africa and Central America. Methods We modelled the distributions of 23 wild Sorghum taxa, characterized their ecogeographic niches, assessed their conservation status both ex situ and in situ and performed preliminary threat assessments. Results Three taxa were categorized as “high priority” for further conservation based on their ex situ and in situ assessments, with a further 19 as “medium priority” and only one as “low priority”. The preliminary threat assessment indicated that 12 taxa may be Endangered, four Vulnerable and four Near Threatened. The taxa fill a wide range of climatic niches, both across and within taxa, including temperatures and precipitation. Main conclusions Taxon richness hotspots, especially in northern Australia, represent hotspots for conservation action, including further seed collection and habitat protection, with Sorghum macrospermum E. D. Garber being the highest priority for increased in situ protection. Outside Australia, Sorghum propinquum (Kunth) Hitchc. stands out for further ex situ conservation, especially given its close relationship to the crop.

In 2009, Food Standards Australia New Zealand set a total cyanide content limit of 10 ppm for ready-to-eat cassava products to address food safety concerns about cyanogenic glucosides in cassava. This study surveys a range of cassava food products available in Melbourne, Australia, ten years after the implementation of these regulations. Of all the products tested, the mean cyanide content was greatest in ready-to-eat cassava chips (48.4 ppm), although imported ready-to-eat products had a higher mean cyanide content (95.9 ppm) than those manufactured in Australia (1.0 ppm). Cyanide was detected in frozen cassava products (grated mean = 12.9 ppm; whole root mean = 19.8 ppm), but was significantly reduced through processing according to packet instructions in both product types. Three methods were used to quantify total cyanide content: the evolved cyanide method, the picrate absorbance method and the picrate chart method, with satisfactory agreement between methods. The picrate absorbance and chart methods reported mean cyanide contents 13.7 ppm and 23.1 ppm higher, respectively, than the evolved cyanide method. Our results reaffirm the need for the ongoing testing of cassava food products, especially ready-to-eat products whose cyanide content will not be reduced before consumption.

Domesticated sorghum (Sorghum bicolor [L.] Moench subsp. bicolor) diverts significant amounts of nitrogen away from primary metabolism to the synthesis of cyanogenic glucosides (CNglc)specialized metabolites that release toxic hydrogen cyanide (HCN). Our aim was to identify the point in the genus Sorghum Moench at which plants gained the ability to maintain hazardous concentrations of cyanogenic glucosides in their leaves into maturity (HCN potential >0.4 mg g À1 ). This ability occurs in domesticated sorghum (in the subgenus Eusorghum), but not in wild taxa in other Sorghum subgenera.• Eight accessions from the subgenus Eusorghum were grown in a common garden: an improved sorghum line, five sorghum landraces, the crop's wild progenitor (S. bicolor subsp. verticilliflorum [Steud.] de Wet ex Wiersema & J. Dahlb.) and wild Sorghum propinquum (Kunth) Hitchc. HCN potential was measured in plants (n = 80) at the three-leaf stage and at 6 weeks old.• All study accessions, including the wild taxa, had hazardous CNglc concentrations in the leaves at both the three-leaf stage (mean HCN potentials > = 2.5 mg g À1 ) and at 6 weeks old (mean HCN potentials > = 0.68 mg g À1 ), greatly contrasting the much lower mature leaf HCN potentials previously found in wild Sorghum taxa outside subgenus Eusorghum (generally <= 0.01 mg g À1 ).• Our results suggest that the ability to maintain hazardous leaf HCN potentials into maturity might have arisen during the divergence of Eusorghum from other Sorghum subgenera, rather than during the speciation or domestication of S. bicolor, and highlights the value of utilizing Sorghum taxa outside Eusorghum in efforts to improve the crop safety of sorghum.