Variability for the presence of pyrrolizidine alkaloids in Crotolaria juncea L.

Sunn hemp (Crotalaria juncea L.) is the most widely grown legume used as green manure in the tropics where it is also grown as a fiber and animal fodder crop. It has been reported that sunn hemp seeds contain several pyrrolizidine alkaloids that when ingested in sufficient amount can be toxic to animals and birds. No information is available regarding variability for the presences of the different types of pyrrolizidine alkaloids in the seeds. The objective of this research was to analyze sunn hemp seeds of nine populations that originated in different parts of the world for several pyrrolizidine alkaloids to determine their level of variability for the presence of these compounds and to quantify the total amount of pyrrolizidine alkaloids in the seeds. Of the nine pyrrolizidine alkaloids tested, the sunn hemp populations only had junceine and trichodesmine. PI 207657 had very low levels of both alkaloids and PI 314239, PI 322377, PI 346297, and the US cultivar Tropic Sun had very low levels of trichodesmine. Although juncein was present in higher amounts than trichodesmine in the seeds of most accessions, its value was deemed to be small. The amount of pyrrolizidine alkaloids present in the sunn hemp populations studied was low.