Cool season grain legumes for Mediterranean environments: the effect of environment on non-protein amino acids in Vicia and Lathyrus species

Abstract

Variation among a range of potentially deleterious non-protein amino acids found in the seeds of the genera Vicia and Lathyrus was determined by growing species at up to 31 sites covering the range of environments experienced in the cropping region of south-west Australia. γ-Glutamyl-S-ethenyl cysteine (GEC) concentrations in V. narbonensis were correlated to seed sulfur levels (r = 0.95, P < 0.001) in 1 of 2 genotypes, and shown to increase under conditions of increasing soil sulfur availability, pH, clay content, cation exchange capacity, concentration of exchangeable cations, and salinity. To capitalise on the agricultural potential of this species we recommend the selection of genotypes that break the linkage between GEC and seed sulfur. In Lathyrus species the degree of variation of β-N-oxalyl-L-α, β-diaminopropionic acid (ODAP) in the seed appears to be proportional to the species mean ODAP concentration; L. ochrus was more responsive than L. sativus, which was in turn more responsive than L. cicera. Seed ODAP concentrations in L. ochrus and L. sativus were positively correlated with soil phosphorus, and negatively correlated with clay content and salinity, and may constrain the species potential for human and animal consumption. In V. ervilia seed, canavanine concentrations were extremely variable in the field (0.01–0.17%), but are unlikely to reduce the stockfeed potential of this species for either monogastrics or ruminants.