Grass pea (Lathyrus sativus L.) has great agronomic potential as grain and forage legume, and presently is considered as a model crop for sustainable agriculture. However, the development into an important food legume has been hin- dered by the presence of the neurotoxic amino acid β-N-Oxalyl-α, β-diaminopropionic acid (β-ODAP). Recent studies reported that homoarginine (Har) can counteract this toxic action. This research was undertaken to shed light on the variation of Har amount within grass pea. The influence of the environment and of the year-to-year variation of cli- matic conditions was also investigated. Seven Italian grass pea ecotypes were evaluated for two subsequent growing seasons in two locations of southern Italy. In contrast with previous studies, collected data evidenced a significant variation of Har amount among the tested ecotypes. Moreover, a significant positive correlation between Har and ODAP level was observed. The effect of year-to-year variation of temperature and rainfall quantity is also discussed.
