Trypsin inhibitory activity measurement: Simplifications of the standard procedure used for pea seed

A major breeding criterion for pea (Pisum sativum L,) is a Low seed trypsin inhibitor activity (TIA), but the high cost of measurement limits the scre ening of new experimental lines. Our objectives were to devise two simplifi ed procedures for screening for TIA using micro titration plates. In the fi rst procedure, the inhibition induced by one single extract is measured. It allows for a rapid ranking of genotypes, but not calculation of seed TIA, Conversely, the second procedure is a titration procedure, where results ar e expressed in conventional trypsin inhibitor units (TIU). The time require d for the measurements is reduced compared with that required with the stan dard procedures, The different methods were performed on cultivars ranging from low to high seed TIA, The results using the screening procedure showed very Low standard deviations and allowed the ranking of the cultivars into three classes according to their seed TIA, The ranking was consistent with results obtained using the standard procedures, Results of the titration p rocedure were not significantly different from results obtained with the st andard procedures on pea lines ranging from 2 to 10 TIU mg(-1) dry weight.