High antinutrient levels and bruchid resistance of cowpea (Vigna unguiculata) seeds.

Seeds of some cowpea varieties, characterized by different degrees of storage pest resistance, were analyzed for inhibitors of the following enzymes: porcine amylase, Bacillus amylase, bovine chymotrypsin and trypsin. A broad variation was observed among samples for all tested inhibitors. Submitting the experimental data to the principal component analysis it has been observed that resistant lines are characterized by high levels of both antitryptic and antiamylasic activity. Moreover a high activity of a single inhibitor class is typical of the bruchid susceptible lines. Hence, breeding for high contents of these protein inhibitors could be an effective way of obtaining lines that are naturally resistant to storage pest attack. The limit of this breeding strategy seems to be the difficulty to reduce the antiamylasic activity before eating.