Trypsin Inhibitor Activity in Field Pea (Pisum sativum L.) and Grass Pea (Lathyrus sativus L.)

Trypsin inhibitors in grain legumes decrease the digestibility of protein and cause pancreatic enlargement. Seed samples of 17 field pea cultivars grown at 5 locations and 9 grass pea lines grown at 2 locations in western Canada during 1993 and 1994 were analyzed for trypsin inhibitor activity (TIA). TIAs in field pea differed significantly among cultivars. Mean TIA in field pea ranged from 2.22 trypsin inhibitor unit (TIU) mg-1 of dry matter (DM) for Danto to 7.66 TIU mg-1 of DM for Baroness. Cultivar accounted for more of the total variability (55%) in field pea than environment (18%). TIAs in grass pea did not differ among cultivars or environments. The mean TIA was 27.51 TIU mg-1 of DM for the grass pea lines tested. The correlation between the levels of TIA and seed yield was near zero in field pea and grass pea. Keywords: Field pea; grass pea; Lathyrus sativus L.; Pisum sativum L.; trypsin inhibitor activity